National Primary Drinking Water Regulations: Stage 2 Disinfectants and Disinfection Byproducts Rule, 388-493 [06-3]
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Federal Register / Vol. 71, No. 2 / Wednesday, January 4, 2006 / Rules and Regulations
ENVIRONMENTAL PROTECTION
AGENCY
40 CFR Parts 9, 141, and 142
[EPA–HQ–OW–2002–0043; FRL–8012–1]
RIN 2040–AD38
National Primary Drinking Water
Regulations: Stage 2 Disinfectants and
Disinfection Byproducts Rule
Environmental Protection
Agency (EPA).
ACTION: Final rule.
AGENCY:
SUMMARY: The Environmental Protection
Agency (EPA) is promulgating today’s
final rule, the Stage 2 Disinfectants and
Disinfection Byproducts Rule (DBPR), to
provide for increased protection against
the potential risks for cancer and
reproductive and developmental health
effects associated with disinfection
byproducts (DBPs). The final Stage 2
DBPR contains maximum contaminant
level goals for chloroform,
monochloroacetic acid and
trichloroacetic acid; National Primary
Drinking Water Regulations, which
consist of maximum contaminant levels
(MCLs) and monitoring, reporting, and
public notification requirements for
total trihalomethanes (TTHM) and
haloacetic acids (HAA5); and revisions
to the reduced monitoring requirements
for bromate. This document also
specifies the best available technologies
for the final MCLs. EPA is also
approving additional analytical methods
for the determination of disinfectants
and DBPs in drinking water. EPA
believes the Stage 2 DBPR will reduce
the potential risks of cancer and
reproductive and developmental health
effects associated with DBPs by
reducing peak and average levels of
DBPs in drinking water supplies.
The Stage 2 DBPR applies to public
water systems (PWSs) that are
community water systems (CWSs) or
nontransient noncommunity water
systems (NTNCWs) that add a primary
or residual disinfectant other than
ultraviolet light or deliver water that has
been treated with a primary or residual
disinfectant other than ultraviolet light.
This rule also makes minor
corrections to drinking water
regulations, specifically the Public
Notification tables. New endnotes were
added to these tables in recent
rulemakings; however, the
corresponding footnote numbering in
the tables was not changed. In addition,
this rule makes a minor correction to the
Stage 1 Disinfectants and Disinfection
Byproducts Rule by replacing a sentence
that was inadvertently removed.
DATES: This final rule is effective on
March 6, 2006. For judicial review
purposes, this final rule is promulgated
as January 4, 2006. The incorporation by
reference of certain publications listed
in the rule is approved by the Director
of the Federal Register as of March 6,
2006.
ADDRESSES: EPA has established a
docket for this action under Docket ID
No. EPA–HQ–OW–2002–0043. All
documents in the docket are listed on
the https://www.regulations.gov Web
site.
Although listed in the index, some
information is not publicly available,
e.g., CBI or other information whose
disclosure is restricted by statute.
Certain other material, such as
copyrighted material, is not placed on
the Internet and will be publicly
available only in hard copy form.
Publicly available docket materials
are available either electronically
through https://www.regulations.gov or
in hard copy at the Water Docket, EPA/
DC, EPA West, Room B102, 1301
Constitution Ave., NW., Washington,
DC. The Public Reading Room is open
from 10 a.m. to 4 p.m., Monday through
Friday, excluding legal holidays. The
telephone number for the Public
Reading Room is (202) 566–1744, and
the telephone number for the Water
Docket is (202) 566–2426.
For
technical inquiries, contact Tom
Grubbs, Standards and Risk
Management Division, Office of Ground
Water and Drinking Water (MC 4607M),
Environmental Protection Agency, 1200
Pennsylvania Ave., NW., Washington,
DC 20460; telephone number: (202)
564–5262; fax number: (202) 564–3767;
e-mail address: grubbs.thomas@epa.gov.
For general information, contact the
Safe Drinking Water Hotline, Telephone
(800) 426–4791. The Safe Drinking
Water Hotline is open Monday through
Friday, excluding legal holidays, from
10 a.m. to 4 p.m. Eastern Time.
FOR FURTHER INFORMATION CONTACT:
SUPPLEMENTARY INFORMATION:
I. General Information
A. Does This Action Apply to Me?
Entities potentially regulated by the
Stage 2 DBPR are community and
nontransient noncommunity water
systems that add a primary or residual
disinfectant other than ultraviolet light
or deliver water that has been treated
with a primary or residual disinfectant
other than ultraviolet light. Regulated
categories and entities are identified in
the following chart.
Category
Examples of regulated entities
Industry ...............................................................
Community and nontransient noncommunity water systems that use a primary or residual disinfectant other than ultraviolet light or deliver water that has been treated with a primary or
residual disinfectant other than ultraviolet light.
Community and nontransient noncommunity water systems that use a primary or residual disinfectant other than ultraviolet light or deliver water that has been treated with a primary or
residual disinfectant other than ultraviolet light.
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State, Local, Tribal, or Federal Governments ....
This table is not intended to be
exhaustive, but rather provides a guide
for readers regarding entities likely to be
regulated by this action. This table lists
the types of entities that EPA is now
aware could potentially be regulated by
this action. Other types of entities not
listed in the table could also be
regulated. To determine whether your
facility is regulated by this action, you
should carefully examine the definition
of ‘‘public water system’’ in § 141.2 and
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the section entitled ‘‘coverage’’ (§ 141.3)
in Title 40 of the Code of Federal
Regulations and applicability criteria in
§ 141.600 and 141.620 of today’s
proposal. If you have questions
regarding the applicability of this action
to a particular entity, contact the person
listed in the preceding FOR FURTHER
INFORMATION CONTACT section.
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B. How Can I Get Copies of This
Document and Other Related
Information?
See the ADDRESSES section for
information on how to receive a copy of
this document and related information.
Regional contacts:
I. Kevin Reilly, Water Supply Section,
JFK Federal Bldg., Room 203,
Boston, MA 02203, (617) 565–3616.
II. Michael Lowy, Water Supply Section,
290 Broadway, 24th Floor, New
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York, NY 10007–1866, (212) 637–
3830.
III. Jason Gambatese, Drinking Water
Section (3WM41), 1650 Arch Street,
Philadelphia, PA 19103–2029, (215)
814–5759.
IV. Robert Burns, Drinking Water
Section, 61 Forsyth Street SW.,
Atlanta, GA 30303, (404) 562–9456.
V. Miguel Del Toral, Water Supply
Section, 77 W. Jackson Blvd.,
Chicago, IL 60604, (312) 886–5253.
VI. Blake L. Atkins, Drinking Water
Section, 1445 Ross Avenue, Dallas,
TX 75202, (214) 665–2297.
VII. Douglas J. Brune, Drinking Water
Management Branch, 901 North 5th
Street, Kansas City, KS 66101, (800)
233–0425.
VIII. Bob Clement, Public Water Supply
Section (8P2-W-MS), 999 18th
Street, Suite 500, Denver, CO
80202–2466, (303) 312–6653.
IX. Bruce Macler, Water Supply Section,
75 Hawthorne Street, San
Francisco, CA 94105, (415) 972–
3569.
X. Wendy Marshall, Drinking Water
Unit, 1200 Sixth Avenue (OW–136),
Seattle, WA 98101, (206) 553–1890.
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Abbreviations Used in This Document
ASDWA Association of State Drinking
Water Administrators
ASTM American Society for Testing
and Materials
AWWA American Water Works
Association
AwwaRF American Water Works
Association Research Foundation
BAT Best available technology
BCAA Bromochloroacetic acid
BDCM Bromodichloromethane
CDBG Community Development Block
Grant
CWS Community water system
DBAA Dibromoacetic acid
DBCM Dibromochloromethane
DBP Disinfection byproduct
DBPR Disinfectants and Disinfection
Byproducts Rule
DCAA Dichloroacetic acid
EA Economic analysis
EC Enhanced coagulation
EDA Ethylenediamine
EPA United States Environmental
Protection Agency
ESWTR Enhanced Surface Water
Treatment Rule
FACA Federal Advisory Committee
Act
GAC Granular activated carbon
GC/ECD Gas chromatography using
electron capture detection
GWR Ground Water Rule
GWUDI Ground water under the direct
influence of surface water
HAA5 Haloacetic acids (five) (sum of
monochloroacetic acid, dichloroacetic
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acid, trichloroacetic acid,
monobromoacetic acid, and
dibromoacetic acid)
HAN Haloacetonitriles
(trichloroacetonitrile,
dichloroacetonitrile,
bromochloroacetonitrile, and
dibromoacetonitrile)
IC Ion chromatograph
IC/ICP–MS Ion chromatograph
coupled to an inductively coupled
plasma mass spectrometer
IDSE Initial distribution system
evaluation
ILSI International Life Sciences
Institute
IESWTR Interim Enhanced Surface
Water Treatment Rule
IPCS International Programme on
Chemical Safety
IRIS Integrated Risk Information
System (EPA)
LOAEL Lowest observed adverse effect
level
LRAA Locational running annual
average
LT1ESTWR Long Term 1 Enhanced
Surface Water Treatment Rule
LT2ESTWR Long Term 2 Enhanced
Surface Water Treatment Rule
MBAA Monobromoacetic acid
MCAA Monochloroacetic acid
MCL Maximum contaminant level
MCLG Maximum contaminant level
goal
M–DBP Microbial and disinfection
byproducts mg/L Milligram per liter
MRL Minimum reporting level
MRDL Maximum residual disinfectant
level
MRDLG Maximum residual
disinfectant level goal
NDMA N-nitrosodimethylamine
NDWAC National Drinking Water
Advisory Council
NF Nanofiltration
NOAEL No Observed Adverse Effect
Level
NODA Notice of data availability
NPDWR National primary drinking
water regulation
NRWA National Rural Water
Association
NTNCWS Nontransient
noncommunity water system
NTP National Toxicology Program
NTTAA National Technology Transfer
and Advancement Act
OMB Office of Management and
Budget
PAR Population attributable risk
PE Performance evaluation
PWS Public water system
RAA Running annual average
RFA Regulatory Flexibility Act
RfD Reference dose
RSC Relative source contribution
RUS Rural Utility Service
SAB Science Advisory Board
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SBAR Small Business Advisory
Review
SBREFA Small Business Regulatory
Enforcement Fairness Act
SDWA Safe Drinking Water Act, or the
‘‘Act,’’ as amended in 1996
SER Small Entity Representative
SGA Small for gestational age
SUVA Specific ultraviolet absorbance
SWAT Surface Water Analytical Tool
SWTR Surface Water Treatment Rule
TC Total coliforms
TCAA Trichloroacetic acid
TCR Total Coliform Rule
THM Trihalomethane
TOC Total organic carbon
TTHM Total trihalomethanes (sum of
four THMs: chloroform,
bromodichloromethane,
dibromochloromethane, and
bromoform)
TWG Technical work group
UMRA Unfunded Mandates Reform
Act
UV 254 Ultraviolet absorption at 254
nm
VSL Value of Statistical Life
WTP Willingness To Pay
Table of Contents
I. General Information
A. Does This Action Apply to Me?
B. How Can I Get Copies of This Document
and Other Related Information?
II. Summary of the Final Rule
A. Why is EPA Promulgating the Stage 2
DBPR?
B. What Does the Stage 2 DBPR Require?
1. Initial Distribution System Evaluation
2. Compliance and monitoring
requirements
3. Operational Evaluation Levels
4. Consecutive systems
C. Correction of § 141.132
III. Background
A. Statutory Requirements and Legal
Authority
B. What is the Regulatory History of the
Stage 2 DBPR and How Were
Stakeholders Involved?
1. Total Trihalomethanes Rule
2. Stage 1 Disinfectants and Disinfection
Byproducts Rule
3. Stakeholder involvement
a. Federal Advisory Committee process
b. Other outreach processes
C. Public Health Concerns to be Addressed
1. What are DBPs?
2. DBP Health Effects
a. Cancer health effects
i. Epidemiology
ii. Toxicology
b. Reproductive and developmental health
effects
i. Epidemiology
ii. Toxicology
c. Conclusions
D. DBP Occurrence and DBP Control
1. Occurrence
2. Treatment
E. Conclusions for Regulatory Action
IV. Explanation of Today’s Action
A. MCLGs
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1. Chloroform MCLG
a. Today’s rule
b. Background and analysis
c. Summary of major comments
2. HAA MCLGs: TCAA and MCAA
a. Today’s rule
b. Background and analysis
c. Summary of major comments
B. Consecutive Systems
1. Today’s Rule
2. Background and analysis
3. Summary of major comments
C. LRAA MCLs for TTHM and HAA5
1. Today’s rule
2. Background and analysis
3. Summary of major comments
D. BAT for TTHM and HAA5
1. Today’s rule
2. Background and analysis
3. Summary of major comments
E. Compliance Schedules
1. Today’s rule
2. Background and analysis
3. Summary of major comments
F. Initial Distribution System Evaluation
(IDSE)
1. Today’s rule
a. Applicability
b. Data collection
i. Standard monitoring
ii. System specific study
iii. 40/30 certification
c. Implementation
2. Background and analysis
a. Standard monitoring
b. Very small system waivers
c. 40/30 certifications
d. System specific studies
e. Distribution System Schematics
3. Summary of major comments
G. Monitoring Requirements and
Compliance Determination for TTHM
and HAA5 MCLs
1. Today’s Rule
a. IDSE Monitoring
b. Routine Stage 2 Compliance Monitoring
i. Reduced monitoring
ii. Compliance determination
2. Background and Analysis
3. Summary of Major Comments
H. Operational Evaluation Requirements
initiated by TTHM and HAA5 Levels
1. Today’s rule
2. Background and analysis
3. Summary of major comments
I. MCL, BAT, and Monitoring for Bromate
1. Today’s rule
2. Background and analysis
a. Bromate MCL
b. Criterion for reduced bromate
monitoring
3. Summary of major comments
J. Public Notice Requirements
1. Today’s rule
2. Background and analysis
3. Summary of major comments
K. Variances and Exemptions
1. Today’s Rule
2. Background and Analysis
a. Variances
b. Affordable Treatment Technologies for
Small Systems
c. Exemptions
3. Summary of major comments
L. Requirements for Systems to Use
Qualified Operators
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M. System Reporting and Recordkeeping
Requirements
1. Today’s rule
2. Summary of major comments
N. Approval of Additional Analytical
Methods
1. Today’s Rule
2. Background and Analysis
O. Laboratory Certification and Approval
1. PE acceptance criteria
a. Today’s rule
b. Background and analysis
c. Summary of major comments
2. Minimum reporting limits
a. Today’s rule
b. Background and analysis
c. Summary of major comments
P. Other regulatory changes
V. State Implementation
A. Today’s rule
1. State Primacy Requirements for
Implementation Flexibility
2. State recordkeeping requirements
3. State reporting requirements
4. Interim primacy
5. IDSE implementation
B. Background and Analysis
C. Summary of Major Comments
VI. Economic Analysis
A. Regulatory Alternatives Considered
B. Analyses that Support Today’s Final
Rule
1. Predicting water quality and treatment
changes
2. Estimating benefits
3. Estimating costs
4. Comparing regulatory alternatives
C. Benefits of the Stage 2 DBPR
1. Nonquantified benefits
2. Quantified benefits
3. Timing of benefits accrual
D. Costs of the Stage 2 DBPR
1. Total annualized present value costs
2. PWS costs
a. IDSE costs
b. PWS treatment costs
c. Monitoring costs
3. State/Primacy agency costs
4. Non-quantified costs
E. Household Costs of the Stage 2 DBPR
F. Incremental Costs and Benefits of the
Stage 2 DBPR
G. Benefits From the Reduction of Cooccurring Contaminants
H. Potential Risks From Other
Contaminants
1. Emerging DBPs
2. N-nitrosamines
3. Other DBPs
I. Effects of the Contaminant on the
General Population and Groups within
the General Population that are
Identified as Likely To Be at Greater Risk
of Adverse Health Effects
J. Uncertainties in the Risk, Benefit, and
Cost Estimates for the Stage 2 DBPR
K. Benefit/Cost Determination for the Stage
2 DBPR
L. Summary of Major Comments
1. Interpretation of health effects studies
2. Derivation of benefits
3. Use of SWAT
5. Unanticipated risk issues
6. Valuation of cancer cases avoided
VII. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory
Planning and Review
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B. Paperwork Reduction Act
C. Regulatory Flexibility Act
D. Unfunded Mandates Reform Act
E. Executive Order 13132: Federalism
F. Executive Order 13175: Consultation
and Coordination With Indian Tribal
Governments
G. Executive Order 13045: Protection of
Children from Environmental Health
Risks and Safety Risks
H. Executive Order 13211: Actions
Concerning Regulations That
Significantly Affect Energy Supply,
Distribution, or Use
I. National Technology Transfer and
Advancement Act
J. Executive Order 12898: Federal Actions
to Address Environmental Justice in
Minority Populations or Low-Income
Populations
K. Consultations with the Science
Advisory Board, National Drinking
Water Advisory Council, and the
Secretary of Health and Human Services
L. Plain Language
M. Analysis of the Likely Effect of
Compliance With the Stage 2 DBPR on
the Technical, Managerial, and Financial
Capacity of Public Water Systems
N. Congressional Review Act
VIII. References
II. Summary of the Final Rule
A. Why is EPA Promulgating the Stage
2 DBPR?
The Environmental Protection Agency
is finalizing the Stage 2 Disinfectants
and Disinfection Byproduct Rule
(DBPR) to reduce potential cancer risks
and address concerns with potential
reproductive and developmental risks
from DBPs. The Agency is committed to
ensuring that all public water systems
provide clean and safe drinking water.
Disinfectants are an essential element of
drinking water treatment because of the
barrier they provide against harmful
waterborne microbial pathogens.
However, disinfectants react with
naturally occurring organic and
inorganic matter in source water and
distribution systems to form
disinfection byproducts (DBPs) that may
pose health risks. The Stage 2 DBPR is
designed to reduce the level of exposure
from DBPs without undermining the
control of microbial pathogens. The
Long Term 2 Enhanced Surface Water
Treatment Rule (LT2ESWTR) is being
finalized and implemented
simultaneously with the Stage 2 DBPR
to ensure that drinking water is
microbiologically safe at the limits set
for DBPs.
Congress required EPA to promulgate
the Stage 2 DBPR as part of the 1996
Safe Drinking Water Act (SDWA)
Amendments (section 1412(b)(2)(C)).
The Stage 2 DBPR augments the Stage
1 DBPR that was finalized in 1998 (63
FR 69390, December 16, 1998) (USEPA
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1998a). The goal of the Stage 2 DBPR is
to target the highest risk systems for
changes beyond those required for Stage
1 DBPR. Today’s rule reflects consensus
recommendations from the Stage 2
Microbial/Disinfection Byproducts (M–
DBP) Federal Advisory Committee (the
Advisory Committee) as well as public
comments.
New information on health effects,
occurrence, and treatment has become
available since the Stage 1 DBPR that
supports the need for the Stage 2 DBPR.
EPA has completed a more extensive
analysis of health effects, particularly
reproductive and developmental
endpoints, associated with DBPs since
the Stage 1 DBPR. Some recent studies
on both human epidemiology and
animal toxicology have shown possible
associations between chlorinated
drinking water and reproductive and
developmental endpoints such as
spontaneous abortion, stillbirth, neural
tube and other birth defects, intrauterine
growth retardation, and low birth
weight. While results of these studies
have been mixed, EPA believes they
support a potential hazard concern.
New epidemiology and toxicology
studies evaluating bladder, colon, and
rectal cancers have increased the weight
of evidence linking these health effects
to DBP exposure. The large number of
people (more than 260 million
Americans) exposed to DBPs and the
potential cancer, reproductive, and
developmental risks have played a
significant role in EPA’s decision to
move forward with regulatory changes
that target lowering DBP exposures
beyond the requirements of the Stage 1
DBPR.
While the Stage 1 DBPR is predicted
to provide a major reduction in DBP
exposure, national survey data suggest
that some customers may receive
drinking water with elevated, or peak,
DBP concentrations even when their
distribution system is in compliance
with the Stage 1 DBPR. Some of these
peak concentrations are substantially
greater than the Stage 1 DBPR maximum
contaminant levels (MCLs) and some
customers receive these elevated levels
of DBPs on a consistent basis. The new
survey results also show that Stage 1
DBPR monitoring sites may not be
representative of higher DBP
concentrations that occur in distribution
systems. In addition, new studies
indicate that cost-effective technologies
including ultraviolet light (UV) and
granular activated carbon (GAC) may be
very effective at lowering DBP levels.
EPA’s analysis of this new occurrence
and treatment information indicates that
significant public health benefits may be
achieved through further, cost-effective
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reductions of DBPs in distribution
systems.
The Stage 2 DBPR presents a risktargeting approach to reduce risks from
DBPs. The new requirements provide
for more consistent, equitable protection
from DBPs across the entire distribution
system and the reduction of DBP peaks.
New risk-targeting provisions require
systems to first identify their risk level;
then, only those systems with the
greatest risk will need to make
operational or treatment changes. The
Stage 2 DBPR, in conjunction with the
LT2ESWTR, will help public water
systems deliver safer water to
Americans with the benefits of
disinfection to control pathogens and
with fewer risks from DBPs.
B. What Does the Stage 2 DBPR Require?
The risk-targeting components of the
Stage 2 DBPR focus the greatest amount
of change where the greatest amount of
risk may exist. Therefore, the provisions
of the Stage 2 DBPR focus first on
identifying the higher risks through the
Initial Distribution System Evaluation
(IDSE). The rule then addresses
reducing exposure and lowering DBP
peaks in distribution systems by using
a new method to determine MCL
compliance (locational running annual
average (LRAA)), defining operational
evaluation levels, and regulating
consecutive systems. This section
briefly describes the requirements of
this final rule. More detailed
information on the regulatory
requirements for this rule can be found
in Section IV.
1. Initial Distribution System Evaluation
The first provision, designed to
identify higher risk systems, is the
Initial Distribution System Evaluation
(IDSE). The purpose of the IDSE is to
identify Stage 2 DBPR compliance
monitoring sites that represent each
system’s highest levels of DBPs. Because
Stage 2 DBPR compliance will be
determined at these new monitoring
sites, only those systems that identify
elevated concentrations of TTHM and
HAA5 will need to make treatment or
process changes to bring the system into
compliance with the Stage 2 DBPR. By
identifying compliance monitoring sites
with the highest concentrations of
TTHM and HAA5 in each system’s
distribution system, the IDSE will offer
increased assurance that MCLs are being
met across the distribution system and
that customers are receiving more
equitable public health protection. Both
treatment changes and awareness of
TTHM and HAA5 levels resulting from
the IDSE will allow systems to better
control for distribution system peaks.
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The IDSE is designed to offer
flexibility to public water systems. The
IDSE requires TTHM and HAA5
monitoring for one year on a regular
schedule that is determined by source
water type and system size.
Alternatively, systems have the option
of performing a site-specific study based
on historical data, water distribution
system models, or other data; and
waivers are available under certain
circumstances. The IDSE requirements
are discussed in Sections IV.E, IV.F.,
and IV.G of this preamble and in
subpart U of the rule language.
2. Compliance and Monitoring
Requirements
As in Stage 1, the Stage 2 DBPR
focuses on monitoring for and reducing
concentrations of two classes of DBPs:
total trihalomethanes (TTHM) and
haloacetic acids (HAA5). These two
groups of DBPs act as indicators for the
various byproducts that are present in
water disinfected with chlorine or
chloramine. This means that
concentrations of TTHM and HAA5 are
monitored for compliance, but their
presence in drinking water is
representative of many other
chlorination DBPs that may also occur
in the water; thus, a reduction in TTHM
and HAA5 generally indicates an overall
reduction of DBPs.
The second provision of the Stage 2
DBPR is designed to address spatial
variations in DBP exposure through a
new compliance calculation (referred to
as locational running annual average)
for TTHM and HAA5 MCLs. The MCL
values remain the same as in the Stage
1. The Stage 1 DBPR running annual
average (RAA) calculation allowed some
locations within a distribution system to
have higher DBP annual averages than
others as long as the system-wide
average was below the MCL. The Stage
2 DBPR bases compliance on a
locational running annual average
(LRAA) calculation, where the annual
average at each sampling location in the
distribution system will be used to
determine compliance with the MCLs of
0.080 mg/L and 0.060 mg/L for TTHM
and HAA5, respectively. The LRAA will
reduce exposures to high DBP
concentrations by ensuring that each
monitoring site is in compliance with
the MCLs as an annual average, while
providing all customers drinking water
that more consistently meets the MCLs.
A more detailed discussion of Stage 2
DBPR MCL requirements can be found
in Sections IV.C, IV.E, and IV.G of this
preamble and in § 141.64(b)(2) and (3)
and subpart V of the rule language.
The number of compliance
monitoring sites is based on the
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population served and the source water
type. EPA believes that populationbased monitoring provides better risktargeting and is easier to implement.
Section IV.G describes population-based
monitoring and how it affects systems
complying with this rule.
The Stage 2 DBPR includes new
MCLGs for chloroform,
monochloroacetic acid, and
trichloroacetic acid, but these new
MCLGs do not affect the MCLs for
TTHM or HAA5.
3. Operational Evaluation Levels
The IDSE and LRAA calculation will
lead to lower DBP concentrations
overall and reduce short term exposures
to high DBP concentrations in certain
areas, but this strengthened approach to
regulating DBPs will still allow
individual DBP samples above the MCL
even when systems are in compliance
with the Stage 2 DBPR. Today’s rule
requires systems that exceed operational
evaluation levels (referred to as
significant excursions in the proposed
rule) to evaluate system operational
practices and identify opportunities to
reduce DBP concentrations in the
distribution system. This provision will
curtail peaks by providing systems with
a proactive approach to remain in
compliance. Operational evaluation
requirements are discussed in greater
detail in Section IV.H.
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4. Consecutive Systems
The Stage 2 DBPR also contains
provisions for regulating consecutive
systems, defined in the Stage 2 DBPR as
public water systems that buy or
otherwise receive some or all of their
finished water from another public
water system. Uniform regulation of
consecutive systems provided by the
Stage 2 DBPR will ensure that
consecutive systems deliver drinking
water that meets applicable DBP
standards, thereby providing better,
more equitable public health protection.
More information on regulation of
consecutive systems can be found in
Sections IV.B, IV.E, and IV.G.
C. Correction of § 141.132
Section 553 of the Administrative
Procedure Act, 5 U.S.C. 553(b)(B),
provides that, when an agency for good
cause finds that notice and public
procedure are impracticable,
unnecessary, or contrary to the public
interest, the agency may issue a rule
without providing prior notice and an
opportunity for public comment. In
addition to promulgating the Stage 2
regulations, this rule also makes a minor
correction to the National Primary
Drinking Water Regulations, specifically
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the Stage 1 Disinfection Byproducts
Rule. This rule corrects a technical error
made in the January 16, 2001, Federal
Register Notice (66 FR 3769) (see page
3770). This rule restores the following
sentence that was inadvertently
removed from § 141.132 (b)(1)(iii),
‘‘Systems on a reduced monitoring
schedule may remain on that reduced
schedule as long as the average of all
samples taken in the year (for systems
which must monitor quarterly) or the
result of the sample (for systems which
must monitor no more frequently than
annually) is no more than 0.060 mg/L
and 0.045 mg/L for TTHMs and HAA5,
respectively.’’ This text had been part of
the original regulation when it was
codified in the CFR on December 16,
1998. However, as a result of a
subsequent amendment to that
regulatory text, the text discussed today
was removed. EPA recognized the error
only after publication of the new
amendment, and is now correcting the
error. EPA is merely restoring to the
CFR language that EPA had
promulgated on December 16, 1998.
EPA is not creating any new rights or
obligations by this technical correction.
Thus, additional notice and public
comment is not necessary. EPA finds
that this constitutes ‘‘good cause’’ under
5 U.S.C. 553(b)(B).
III. Background
A combination of factors influenced
the development of the Stage 2 DBPR.
These include the initial 1992–1994
Microbial and Disinfection Byproduct
(M–DBP) stakeholder deliberations and
EPA’s Stage 1 DBPR proposal (USEPA
1994); the 1996 Safe Drinking Water Act
(SDWA) Amendments; the 1996
Information Collection Rule; the 1998
Stage 1 DBPR; new data, research, and
analysis on disinfection byproduct
(DBP) occurrence, treatment, and health
effects since the Stage 1 DBPR; and the
Stage 2 DBPR Microbial and
Disinfection Byproducts Federal
Advisory Committee. The following
sections provide summary background
information on these subjects. For
additional information, see the
proposed Stage 2 DBPR and supporting
technical material where cited (68 FR
49548, August 18, 2003) (USEPA
2003a).
A. Statutory Requirements and Legal
Authority
The SDWA, as amended in 1996,
authorizes EPA to promulgate a national
primary drinking water regulation
(NPDWR) and publish a maximum
contaminant level goal (MCLG) for any
contaminant the Administrator
determines ‘‘may have an adverse effect
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on the health of persons,’’ is ‘‘known to
occur or there is a substantial likelihood
that the contaminant will occur in
public water systems with a frequency
and at levels of public health concern,’’
and for which ‘‘in the sole judgement of
the Administrator, regulation of such
contaminant presents a meaningful
opportunity for health risk reduction for
persons served by public water
systems’’ (SDWA section 1412(b)(1)(A)).
MCLGs are non-enforceable health goals
set at a level at which ‘‘no known or
anticipated adverse effects on the health
of persons occur and which allows an
adequate margin of safety.’’ These
health goals are published at the same
time as the NPDWR (SDWA sections
1412(b)(4) and 1412(a)(3)).
SDWA also requires each NPDWR for
which an MCLG is established to
specify an MCL that is as close to the
MCLG as is feasible (sections 1412(b)(4)
and 1401(1)(C)). The Agency may also
consider additional health risks from
other contaminants and establish an
MCL ‘‘at a level other than the feasible
level, if the technology, treatment
techniques, and other means used to
determine the feasible level would
result in an increase in the health risk
from drinking water by—(i) increasing
the concentration of other contaminants
in drinking water; or (ii) interfering with
the efficacy of drinking water treatment
techniques or processes that are used to
comply with other national primary
drinking water regulations’’ (section
1412(b)(5)(A)). When establishing an
MCL or treatment technique under this
authority, ‘‘the level or levels or
treatment techniques shall minimize the
overall risk of adverse health effects by
balancing the risk from the contaminant
and the risk from other contaminants
the concentrations of which may be
affected by the use of a treatment
technique or process that would be
employed to attain the maximum
contaminant level or levels’’ (section
1412(b)(5)(B)). In today’s rule, the
Agency is establishing MCLGs and
MCLs for certain DBPs, as described in
Section IV.
Finally, section 1412(b)(2)(C) of the
Act requires EPA to promulgate a Stage
2 DBPR. Consistent with statutory
provisions for risk balancing (section
1412(b)(5)(B)), EPA is finalizing the
LT2ESWTR concurrently with the Stage
2 DBPR to ensure simultaneous
protection from microbial and DBP
risks.
B. What is the Regulatory History of the
Stage 2 DBPR and How Were
Stakeholders Involved?
This section first summarizes the
existing regulations aimed at controlling
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levels of DBPs in drinking water. The
Stage 2 DBPR establishes regulatory
requirements beyond these rules that
target high risk systems and provide for
more equitable protection from DBPs
across the entire distribution system.
Next, this section summarizes the
extensive stakeholder involvement in
the development of the Stage 2 DBPR.
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1. Total Trihalomethanes Rule
The first rule to regulate DBPs was
promulgated on November 29, 1979.
The Total Trihalomethanes Rule (44 FR
68624, November 29, 1979) (USEPA
1979) set an MCL of 0.10 mg/L for total
trihalomethanes (TTHM). Compliance
was based on the running annual
average (RAA) of quarterly averages of
all samples collected throughout the
distribution system. This TTHM
standard applied only to community
water systems using surface water and/
or ground water that served at least
10,000 people and added a disinfectant
to the drinking water during any part of
the treatment process.
2. Stage 1 Disinfectants and Disinfection
Byproducts Rule
The Stage 1 DBPR, finalized in 1998
(USEPA 1998a), applies to all
community and nontransient
noncommunity water systems that add
a chemical disinfectant to water. The
rule established maximum residual
disinfectant level goals (MRDLGs) and
enforceable maximum residual
disinfectant level (MRDL) standards for
three chemical disinfectants—chlorine,
chloramine, and chlorine dioxide;
maximum contaminant level goals
(MCLGs) for three trihalomethanes
(THMs), two haloacetic acids (HAAs),
bromate, and chlorite; and enforceable
maximum contaminant level (MCL)
standards for TTHM, five haloacetic
acids (HAA5), bromate (calculated as
running annual averages (RAAs)), and
chlorite (based on daily and monthly
sampling). The Stage 1 DBPR uses
TTHM and HAA5 as indicators of the
various DBPs that are present in
disinfected water. Under the Stage 1
DBPR, water systems that use surface
water or ground water under the direct
influence of surface water and use
conventional filtration treatment are
required to remove specified
percentages of organic materials,
measured as total organic carbon (TOC),
that may react with disinfectants to form
DBPs. Removal is achieved through
enhanced coagulation or enhanced
softening, unless a system meets one or
more alternative compliance criteria.
The Stage 1 DBPR was one of the first
rules to be promulgated under the 1996
SDWA Amendments (USEPA 1998a).
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EPA finalized the Interim Enhanced
Surface Water Treatment Rule (63 FR
69477, December 16, 1998) (USEPA
1998b) at the same time as the Stage 1
DBPR to ensure simultaneous
compliance and address risk tradeoff
issues. Both rules were products of
extensive Federal Advisory Committee
deliberations and final consensus
recommendations in 1997.
3. Stakeholder Involvement
a. Federal Advisory Committee
process. EPA reconvened the M-DBP
Advisory Committee in March 1999 to
develop recommendations on issues
pertaining to the Stage 2 DBPR and
LT2ESWTR. The Stage 2 M-DBP
Advisory Committee consisted of 21
organizational members representing
EPA, State and local public health and
regulatory agencies, local elected
officials, Native American Tribes, large
and small drinking water suppliers,
chemical and equipment manufacturers,
environmental groups, and other
stakeholders. Technical support for the
Advisory Committee’s discussions was
provided by a technical working group
established by the Advisory Committee.
The Advisory Committee held ten
meetings from September 1999 to July
2000, which were open to the public,
with an opportunity for public comment
at each meeting.
The Advisory Committee carefully
considered extensive new data on the
occurrence and health effects of DBPs,
as well as costs and potential impacts
on public water systems. In addition,
they considered risk tradeoffs associated
with treatment changes. Based upon this
detailed technical evaluation, the
committee concluded that a targeted
protective public health approach
should be taken to address exposure to
DBPs beyond the requirements of the
Stage 1 DBPR. While there had been
substantial research to date, the
Advisory Committee also concluded
that significant uncertainty remained
regarding the risk associated with DBPs
in drinking water. After reaching these
conclusions, the Advisory Committee
developed an Agreement in Principle
(65 FR 83015, December 29, 2000)
(USEPA 2000a) that laid out their
consensus recommendations on how to
further control DBPs in public water
systems, which are reflected in today’s
final rule.
In the Agreement in Principle, the
Advisory Committee recommended
maintaining the MCLs for TTHM and
HAA5 at 0.080 mg/L and 0.060 mg/L,
respectively, but changing the
compliance calculation in two phases to
facilitate systems moving from the
running annual average (RAA)
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393
calculation to a locational running
annual average (LRAA) calculation. In
the first phase, systems would continue
to comply with the Stage 1 DBPR MCLs
as RAAs and, at the same time, comply
with MCLs of 0.120 mg/L for TTHM and
0.100 mg/L for HAA5 calculated as
LRAAs. RAA calculations average all
samples collected within a distribution
system over a one-year period, but
LRAA calculations average all samples
taken at each individual sampling
location in a distribution system during
a one-year period. Systems would also
carry out an Initial Distribution System
Evaluation (IDSE) to select compliance
monitoring sites that reflect higher
TTHM and HAA5 levels occurring in
the distribution system. The second
phase of compliance would require
MCLs of 0.080 mg/L for TTHM and
0.060 mg/L for HAA5, calculated as
LRAAs at individual monitoring sites
identified through the IDSE. The first
phase has been dropped in the final
rule, as discussed in section IV.C.
The Agreement in Principle also
provided recommendations for
simultaneous compliance with the
LT2ESWTR so that the reduction of
DBPs does not compromise microbial
protection. The complete text of the
Agreement in Principle (USEPA 2000a)
can be found online at
www.regulations.gov.
b. Other outreach processes. EPA
worked with stakeholders to develop
the Stage 2 DBPR through various
outreach activities other than the MDBP Federal Advisory Committee
process. The Agency consulted with
State, local, and Tribal governments; the
National Drinking Water Advisory
Committee (NDWAC); the Science
Advisory Board (SAB); and Small Entity
Representatives (SERs) and small
system operators (as part of an Agency
outreach initiative under the Regulatory
Flexibility Act). Section VII includes a
complete description of the many
stakeholder activities which contributed
to the development of the Stage 2 DBPR.
Additionally, EPA posted a preproposal draft of the Stage 2 DBPR
preamble and regulatory language on an
EPA Internet site on October 17, 2001.
This public review period allowed
readers to comment on the Stage 2
DBPR’s consistency with the Agreement
in Principle of the Stage 2 M-DBP
Advisory Committee. EPA received
important suggestions on this preproposal draft from 14 commenters,
which included public water systems,
State governments, laboratories, and
other stakeholders.
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C. Public Health Concerns to be
Addressed
EPA is promulgating the Stage 2 rule
to reduce the potential risks of cancer
and reproductive and developmental
health effects from DBPs. In addition,
the provisions of the Stage 2 DBPR
provide for more equitable public health
protection. Sections C and D describe
the general basis for this public health
concern through reviewing information
in the following areas: the health effects
associated with DBPs, DBP occurrence,
and the control of DBPs.
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1. What Are DBPs?
Chlorine has been widely used to kill
disease-causing microbes in drinking
water. The addition of chlorine in PWSs
across the U.S. to kill microbial
pathogens in the water supply has been
cited as one of the greatest public health
advances of the twentieth century
(Okun 2003). For example, during the
decade 1880–1890, American cities
experienced an average mortality rate of
58 per 100,000 from typhoid, which was
commonly transmitted through
contaminated water. By 1938, this rate
had fallen to 0.67 deaths per 100,000,
largely due to improved treatment of
drinking water (Blake 1956).
During the disinfection process,
organic and inorganic material in source
waters can combine with chlorine and
certain other chemical disinfectants to
form DBPs. More than 260 million
people in the U.S. are exposed to
disinfected water and DBPs (USEPA
2005a). Although chlorine is the most
commonly applied disinfectant, other
disinfectants, including ozone, chlorine
dioxide, chloramine, and ultraviolet
radiation, are in use. In combination
with these, all surface water systems
must also use either chlorine or
chloramine to maintain a disinfectant
residual in their distribution system.
The kind of disinfectant used can
produce different types and levels of
disinfectant byproducts in the drinking
water.
Many factors affect the amount and
kinds of DBPs in drinking water. Areas
in the distribution system that have had
longer contact time with chemical
disinfectants tend to have higher levels
of DBPs, such as sites farther from the
treatment plant, dead ends in the
system, and small diameter pipes. The
makeup and source of the water also
affect DBP formation. Different types of
organic and inorganic material will form
different types and levels of DBPs. Other
factors, such as water temperature,
season, pH, and location within the
water purification process where
disinfectants are added, can affect DBP
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formation within and between water
systems.
THMs and HAAs are widely occurring
classes of DBPs formed during
disinfection with chlorine and
chloramine. The four THMs (TTHM)
and five HAAs (HAA5) measured and
regulated in the Stage 2 DBPR act as
indicators for DBP occurrence. There are
other known DBPs in addition to a
variety of unidentified DBPs present in
disinfected water. THMs and HAAs
typically occur at higher levels than
other known and unidentified DBPs
(McGuire et al. 2002; Weinberg et al.
2002). The presence of TTHM and
HAA5 is representative of the
occurrence of many other chlorination
DBPs; thus, a reduction in the TTHM
and HAA5 generally indicates an overall
reduction of DBPs.
2. DBP Health Effects
Since the mid 1980’s, epidemiological
studies have supported a potential
association between bladder cancer and
chlorinated water and possibly also
with colon and rectal cancers. In
addition, more recent health studies
have reported potential associations
between chlorinated drinking water and
reproductive and developmental health
effects.
Based on a collective evaluation of
both the human epidemiology and
animal toxicology data on cancer and
reproductive and developmental health
effects discussed below and in
consideration of the large number of
people exposed to chlorinated
byproducts in drinking water (more
than 260 million), EPA concludes that
(1) new cancer data since Stage 1
strengthen the evidence of a potential
association of chlorinated water with
bladder cancer and suggests an
association for colon and rectal cancers,
(2) current reproductive and
developmental health effects data do not
support a conclusion at this time as to
whether exposure to chlorinated
drinking water or disinfection
byproducts causes adverse
developmental or reproductive health
effects, but do support a potential health
concern, and (3) the combined health
data indicate a need for public health
protection beyond that provided by the
Stage 1 DBPR.
This section summarizes the key
information in the areas of cancer,
reproductive, and developmental health
studies that EPA used to arrive at these
conclusions. Throughout this writeup,
EPA uses ‘weight of evidence,’
‘causality,’ and ‘hazard’ as follows:
• A ‘weight of evidence’ evaluation is
a collective evaluation of all pertinent
information. Judgement about the
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weight of evidence involves
considerations of the quality and
adequacy of data and consistency of
responses. These factors are not scored
mechanically by adding pluses and
minuses; they are judged in
combination.
• Criteria for determining ‘causality’
include consistency, strength, and
specificity of association, a temporal
relationship, a biological gradient (doseresponse relationship), biological
plausibility, coherence with multiple
lines of evidence, evidence from human
populations, and information on agent’s
structural analogues (USEPA 2005i).
Additional considerations for individual
study findings include reliable exposure
data, statistical power and significance,
and freedom from bias and
confounding.
• The term ‘hazard’ describes not a
definitive conclusion, but the possibility
that a health effect may be attributed to
a certain exposure, in this case
chlorinated water. Analyses done for the
Stage 2 DBPR follow the 1999 EPA
Proposed Guidelines for Carcinogenic
Risk Assessment (USEPA 1999a). In
March 2005, EPA updated and finalized
the Cancer Guidelines and a
Supplementary Children’s Guidance,
which include new considerations on
mode of action for cancer risk
determination and additional potential
risks due to early childhood exposure
(USEPA 2005i; USEPA 2005j).
Conducting the cancer evaluation using
the 2005 Cancer Guidelines would not
result in any change from the existing
analysis. With the exception of
chloroform, no mode of action has been
established for other specific regulated
DBPs. Although some of the DBPs have
given mixed mutagenicity and
genotoxicity results, having a positive
mutagenicity study does not necessarily
mean that a chemical has a mutagenic
mode of action. The extra factor of
safety for children’s health protection
does not apply because the new
Supplementary Children’s Guidance
requires application of the children’s
factor only when a mutagenic mode of
action has been identified.
a. Cancer health effects. The following
section briefly discusses cancer
epidemiology and toxicology
information EPA analyzed and some
conclusions of these studies and reports.
Further discussion of these studies and
EPA’s conclusions can be found in the
proposed Stage 2 DBPR (USEPA 2003a)
and the Economic Analysis for the Final
Stage 2 Disinfectants and Disinfection
Byproducts Rule (Economic Analysis
(EA)) (USEPA 2005a).
Human epidemiology studies and
animal toxicology studies have
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examined associations between
chlorinated drinking water or DBPs and
cancer. While EPA cannot conclude
there is a causal link between exposure
to chlorinated surface water and cancer,
EPA believes that the available research
indicates a potential association
between bladder cancer and exposure to
chlorinated drinking water or DBPs.
EPA also believes the available research
suggests a possible association between
rectal and colon cancers and exposure
to chlorinated drinking water or DBPs.
This is based on EPA’s evaluation of all
available cancer studies. The next two
sections focus on studies published
since the Stage 1 DBPR. Conclusions are
based on the research as a whole.
i. Epidemiology. A number of
epidemiological studies have been
conducted to investigate the
relationship between exposure to
chlorinated drinking water and various
cancers. These studies contribute to the
overall evidence on potential human
health hazards from exposure to
chlorinated drinking water.
Epidemiology studies provide useful
health effects information because they
reflect human exposure to a drinking
water DBP mixture through multiple
routes of intake such as ingestion,
inhalation and dermal absorption. The
greatest difficulty with conducting
cancer epidemiology studies is the
length of time between exposure and
effect. Higher quality studies have
adequately controlled for confounding
and have limited the potential for
exposure misclassification, for example,
using DBP levels in drinking water as
the exposure metric as opposed to type
of source water. Study design
considerations for interpreting cancer
epidemiology data include sufficient
follow-up time to detect disease
occurrence, adequate sample size, valid
ascertainment of cause of the cancer,
and reduction of potential selection bias
in case-control and cohort studies (by
having comparable cases and controls
and by limiting loss to follow-up).
Epidemiology studies provide extremely
useful information on human exposure
to chlorinated water, which
complement single chemical, high dose
animal data.
In the Stage 1 DBPR, EPA concluded
that the epidemiological evidence
suggested a potential increased risk for
bladder cancer. Some key studies EPA
considered for Stage 1 include Cantor et
al. (1998), Doyle et al. (1997), Freedman
et al. (1997), King and Marrett (1996),
McGeehin et al. (1993), Cantor et al.
(1987), and Cantor et al. (1985). Several
studies published since the Stage 1
DBPR continue to support an
association between increased risk of
bladder cancer and exposure to
chlorinated surface water (Chevrier et
al. 2004; Koivusalo et al. 1998; Yang et
al. 1998). One study found no effects on
a biomarker of genotoxicity in urinary
bladder cells from TTHM exposure
(Ranmuthugala et al. 2003).
Epidemiological reviews and metaanalyses generally support the
possibility of an association between
chlorinated water or THMs and bladder
cancer (Villanueva et al. 2004;
Villanueva et al. 2003; Villanueva et al.
2001; Mills et al. 1998). The World
Health Organization (WHO 2000) found
data inconclusive or insufficient to
determine causality between
chlorinated water and any health
endpoint, although they concluded that
the evidence is better for bladder cancer
than for other cancers.
In the Stage 1 DBPR, EPA concluded
that early studies suggested a small
possible increase in rectal and colon
cancers from exposure to chlorinated
395
surface waters. The database of studies
on colon and rectal cancers continues to
support a possible association, but
evidence remains mixed. For colon
cancer, one newer study supports the
evidence of an association (King et al.
2000a) while others showed
inconsistent findings (Hildesheim et al.
1998; Yang et al. 1998). Rectal cancer
studies are also mixed. Hildesheim et al.
(1998) and Yang et al. (1998) support an
association with rectal cancer while
King et al. (2000a) did not. A review of
colon and rectal cancer concluded
evidence was inconclusive but that
there was a stronger association for
rectal cancer and chlorination DBPs
than for colon cancer (Mills et al. 1998).
The WHO (2000) review reported that
studies showed weak to moderate
associations with colon and rectal
cancers and chlorinated surface water or
THMs but that evidence is inadequate to
evaluate these associations.
Recent studies on kidney, brain, and
lung cancers and DBP exposure support
a possible association (kidney: Yang et
al. 1998, Koivusalo et al. 1998; brain:
Cantor et al. 1999; lung: Yang et al.
1998). However, so few studies have
examined these endpoints that
definitive conclusions cannot be made.
Studies on leukemia found little or no
association with DBPs (Infante-Rivard et
al. 2002; Infante-Rivard et al. 2001). A
recent study did not find an association
between pancreatic cancer and DBPs
(Do et al. 2005). A study researching
multiple cancer endpoints found an
association between THM exposure and
all cancers when grouped together
(Vinceti et al. 2004). More details on the
cancer epidemiology studies since the
Stage 1 DBPR are outlined in Table II.D–
1.
TABLE II.D–1.—SUMMARY OF CANCER EPIDEMIOLOGY STUDIES REVIEWED FOR STAGE 2 DBPR
Study type
Author(s)
Do et al. 2005
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2004..
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Exposure(s) studied
Outcome(s)
measured
Findings
Case-control
study in
Canada,
1994–1997.
Case-control
study in
France,
1985–1987.
Estimated chlorinated DBPs,
chloroform, BDCM concentrations.
Pancreatic cancer.
No association was found between pancreatic cancer and
exposure to chlorinated DBPs, chloroform, or BDCM.
Compared THM levels, duration of exposure, and 3
types of water treatment
(ozonation, chlorination,
ozonation/chlorination).
Bladder cancer.
A statistically significant decreased risk of bladder cancer
was found as duration of exposure to ozonated water increased. This was evident with and without adjustment
for other exposure measures. A small association was
detected for increased bladder cancer risk and duration
of exposure to chlorinated surface water and with the estimated THM content of the water, achieving statistical
significance only when adjusted for duration of ozonated
water exposures. Effect modification by gender was
noted in the adjusted analyses.
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TABLE II.D–1.—SUMMARY OF CANCER EPIDEMIOLOGY STUDIES REVIEWED FOR STAGE 2 DBPR—Continued
Study type
Exposure(s) studied
Outcome(s)
measured
Vinceti et al.
2004.
Retrospective
cohort study
in Italy,
1987–1999.
Standardized mortality ratios
from all causes vs. cancer
for consumers drinking
water with high THMs.
15 cancers including colon,
rectum, and
bladder.
Ranmuthugala
et al. 2003.
Cohort study
in 3 Australian communities,
1997.
Populationbased casecontrol study
in Quebec,
1980–1993.
Populationbased casecontrol study
in Quebec,
1980–1993.
Infante-Rivard
et al. 2002.
Infante-Rivard
et al. 2001.
Populationbased casecontrol study
in southern
Ontario,
1992–1994.
Cantor et al.
1999.
Populationbased casecontrol study
in Iowa,
1984–1987.
Cantor et al.
1998.
Populationbased casecontrol study
in Iowa,
1986–1989.
Hildesheim et
al. 1998.
Populationbased casecontrol study
in Iowa,
1986–1989.
Koivusalo et
al. 1998.
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King et al.
2000a.
Populationbased casecontrol study
in Finland,
1991–1992.
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Findings
Mortality ratio from all cancers showed a statistically significant small increase for males consuming drinking water
with high THMs. For females, an increased mortality ratio
for all cancers was seen but was not statistically significant. Stomach cancer in men was the only individual
cancer in which a statistically significant excess in mortality was detected for consumption of drinking water with
high THMs.
Estimated dose of TTHM,
Frequency of
Relative risk estimates for DNA damage to bladder cells for
chloroform, and bromoform
micronuclei in
THM dose metrics were near 1.0. The study provides no
from routinely-collected
urinary bladevidence that THMs are associated with DNA damage to
THM measurements and
der epithelial
bladder epithelial cells, and dose-response patterns were
fluid intake diary.
cells.
not detected.
Estimated prenatal and postAcute
Data are suggestive, but imprecise, linking DNA variants
natal exposure to THMs
lymphoblastic
with risk of acute lymphoblastic leukemia associated with
and polymorphisms in two
leukemia.
drinking water DBPs. The number of genotyped subjects
genes.
for GSTT1 and CYP2E1 genes was too small to be conclusive.
Compared water chlorination
Acute
No increased risk for lymphoblastic leukemia was observed
(never, sometimes, always)
lymphoblastic
for prenatal exposure at average levels of TTHMs, metand exposure to TTHMs,
leukemia.
als or nitrates. However, a non-statistically significant,
metals, and nitrates.
small increased risk was seen for postnatal cumulative
exposure to TTHMs and chloroform (both at above the
95th exposure percentile of the distribution for cases and
controls), for zinc, cadmium, and arsenic, but not other
metals or nitrates.
Compared source of drinking Colon and recColon cancer risk was statistically associated with cumuwater and chlorination statal cancer.
lative long term exposure to THMs, chlorinated surface
tus. Estimated TTHM levwater, and tap water consumption metrics among males
els, duration of exposure,
only. Exposure-response relationships were evident for
and tap water consumption.
exposure measures combining duration and THM levels.
Associations between the exposure measures and rectal
cancer were not observed for either gender.
Compared level and duration Brain cancer .... Among males, a statistically significant increased risk of
of THM exposure (cumubrain cancer was detected for duration of chlorinated
lative and average), source
versus non-chlorinated source water, especially among
of water, chlorination, and
high-level consumers of tap water. An increased risk of
water consumption.
brain cancer for high water intake level was found in
men. No associations were found for women for any of
the exposure metrics examined.
Compared level and duration Bladder cancer A statistically significant positive association between risk
of THM exposure (cumuof bladder cancer and exposure to chlorinated groundlative and average), source
water or surface water reported for men and for smokers,
of water, chlorination, and
but no association found for male/female non-smokers,
water consumption.
or for women overall. Limited evidence was found for an
association between tapwater consumption and bladder
cancer risk. Suggestive evidence existed for exposure-response effects of chlorinated water and lifetime THM
measures on bladder cancer risk.
Compared level and duration Colon and recIncreased risks of rectal cancer was associated with duraof THM exposure (cumutal cancer.
tion of exposure to chlorinated surface water and any
lative and average), source
chlorinated water, with evidence of an exposure-reof water, chlorination, and
sponse relationship. Risk of rectal cancer is statistically
water consumption.
significant increased with >60 years lifetime exposure to
THMs in drinking water, and risk increased for individuals
with low dietary fiber intake. Risks were similar for men
and women and no effects were observed for tapwater
measures. No associations were detected for water exposure measures and risk of colon cancer.
Estimated residential duration Bladder and
Drinking water mutagenicity was associated with a small,
of exposure and level of
kidney cancer.
statistically significant, exposure-related excess risk for
drinking water mutagenicity.
kidney and bladder cancers among men; weaker associations were detected for mutagenic water and bladder
or kidney cancer among women. The effect of mutagenicity on bladder cancer was modified by smoking status,
with an increased risk among non-smokers.
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397
TABLE II.D–1.—SUMMARY OF CANCER EPIDEMIOLOGY STUDIES REVIEWED FOR STAGE 2 DBPR—Continued
Outcome(s)
measured
Study type
Exposure(s) studied
Yang et al.
1998.
Cross-sectional study
in Taiwan,
1982–1991.
Examined residence in
chlorinated (mainly surface
water sources) relative to
non-chlorinated (mainly private well) water.
Doyle et al.
1997.
Prospective
cohort study
in Iowa,
1987–1993.
Examined chloroform levels
and source of drinking
water.
Freedman et
al. 1997.
Populationbased casecontrol study
in Maryland,
1975–1992.
Estimated duration of exposure to chlorinated water.
Compared exposure to
chlorinated municipal water
(yes/no).
King and
Case-control
Marrett 1996.
study in Ontario, Canada, 1992–
1994.
Compared source of drinking
water and chlorination status. Estimated TTHM levels, duration of exposure,
and tap water consumption.
McGeehin et
al. 1993.
Populationbased casecontrol study
in Colorado,
1990–1991.
Compared source of drinking
water, water treatment, and
tap water versus bottled
water. Estimated duration
of exposure to TTHMs and
levels of TTHMs, nitrates,
and residual chlorine.
Cantor et al.
1987 (and
Cantor et al.
1985).
Populationbased casecontrol study
in 10 areas
of the U.S.,
1977–1978.
Compared source of drinking
water. Estimated total beverage and tap water consumption and duration of
exposure.
Review and
meta-analysis of 6
case-control
studies.
Individual-based exposure
estimates to THMs and
water consumption over a
40-year period.
Bladder cancer
Review and
meta-analysis of 6
case-control
studies and
2 cohort
studies.
Compared source of water
and estimated duration of
exposure to chlorinated
drinking water.
Bladder cancer
Reviews/Metaanalyses
Villanueva et
al. 2004.
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Villanueva et
al. 2003
(and Goebell
et al. 2004).
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Findings
Cancer of recResidence in chlorinating municipalities (vs. nontum, lung,
chlorinating) was statistically significantly associated with
bladder, kidthe following types of cancer in both males and females:
ney, colon,
rectal, lung, bladder, and kidney cancer. Liver cancer
and 11 others.
and all cancers were also statistically significantly elevated in chlorinated towns for males only. Mortality rates
for cancers of the esophagus, stomach, colon, pancreas,
prostate, brain, breast, cervix uteri and uterus, and ovary
were comparable for chlorinated and non-chlorinated residence.
Colon, rectum,
Statistically significant increased risk of colon cancer,
bladder, and
breast cancer and all cancers combined was observed
8 other canfor women exposed to chloroform in drinking water, with
cers in
evidence of exposure-response effects. No associations
women.
were detected between chloroform and bladder, rectum,
kidney, upper digestive organs, lung, ovary, endometrium, or breast cancers, or for melanomas or nonHodgkin’s lymphoma. Surface water exposure (compared
to ground water users) was also a significant predictor of
colon and breast cancer risk.
Bladder cancer There was a weak association between bladder cancer risk
and duration of exposure to municipal water for male cigarette smokers, as well as an exposure-response relationship. No association was seen for those with no history of smoking, suggesting that smoking may modify a
possible effect of chlorinated surface water on the risk of
bladder cancer.
Bladder cancer Statistically significant associations were detected for bladder cancer and chlorinated surface water, duration or
concentration of THM levels and tap water consumption
metrics. Population attributable risks were estimated at
14 to 16 percent. An exposure-response relationship was
observed for estimated duration of high THM exposures
and risk of bladder cancer.
Bladder cancer Statistically significant associations were detected for bladder cancer and duration of exposure to chlorinated surface water. The risk was similar for males and females
and among nonsmokers and smokers. The attributable
risk was estimated at 14.9 percent. High tap water intake
was associated with risk of bladder cancer in a exposure-response fashion. No associations were detected
between bladder cancer and levels of TTHMs, nitrates,
and residual chlorine.
Bladder cancer Bladder cancer was statistically associated with duration of
exposure to chlorinated surface water for women and
nonsmokers of both sexes. The largest risks were seen
when both exposure duration and level of tap water ingestion were combined. No association was seen for
total beverage consumption.
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The meta-analysis suggests that risk of bladder cancer in
men increases with long-term exposure to TTHMs. An
exposure-response pattern was observed among men
exposed to TTHMs, with statistically significant risk seen
at exposures higher than 50 ug/L. No association between TTHMs and bladder cancer was seen for women.
The meta-analysis findings showed a moderate excess risk
of bladder cancer attributable to long-term consumption
of chlorinated drinking water for both genders, particularly in men. Statistically significance seen with men and
combined both sexes. The risk was higher when exposure exceeded 40 years.
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TABLE II.D–1.—SUMMARY OF CANCER EPIDEMIOLOGY STUDIES REVIEWED FOR STAGE 2 DBPR—Continued
Study type
Exposure(s) studied
Outcome(s)
measured
Findings
Villanueva et
al. 2001.
Qualitative review of 31
cancer studies.
Compared exposure to TTHM
levels, mutagenic drinking
water, water consumption,
source water, types of disinfection (chlorination and
chloramination), and residence times.
Cancer of bladder, colon,
rectum, and 5
other cancers..
WHO 2000 .....
Qualitative reviews of various studies
in Finland,
U.S., and
Canada.
Various exposures to THMs.
Various cancers
Mills et al.
1998.
Qualitative review of 22
studies.
Examined TTHM levels and
water consumption. Compared source of water and
2 types of water treatment
(chlorination and
chloramination).
Cancer of
colon, rectum, and
bladder.
Review found that although results for cancer studies varied and were not always statistically significant, evidence
for bladder cancer is strongest, and all 10 of the bladder
cancer studies showed increased cancer risks with ingestion of chlorinated water. The authors felt associations with chlorinated water and cancer of the colon, rectum, pancreas, esophagus, brain, and other cancers
were inconsistent.
Studies reviewed reported weak to moderate increased relative risks of bladder, colon, rectal, pancreatic, breast,
brain or lung cancer associated with long-term exposure
to chlorinated drinking water. The authors felt evidence is
inconclusive for an association between colon cancer
and long-term exposure to THMs; that evidence is insufficient to evaluate a causal relationship between THMs
and rectal, bladder, and other cancers. They found no
association between THMs and increased risk of cardiovascular disease.
Review suggests possible increases in risks of bladder
cancer with exposure to chlorinated drinking water. The
authors felt evidence for increased risk of colon and rectal cancers is inconclusive, though evidence is stronger
for rectal cancer.
Overall, bladder cancer data provide
the strongest basis for quantifying
cancer risks from DBPs. EPA has chosen
this endpoint to estimate the primary
benefits of the Stage 2 DBPR (see
Section VI).
ii. Toxicology. Cancer toxicology
studies provide additional support that
chlorinated water is associated with
cancer. In general, EPA uses long term
toxicology studies that show a dose
response to derive MCLGs and cancer
potency factors. Short term studies are
used for hazard identification and to
design long term studies. Much of the
available cancer toxicology information
was available for the Stage 1 DBPR, but
there have also been a number of new
cancer toxicology and mode of action
studies completed since the Stage 1
DBPR was finalized in December 1998.
In support of this rule, EPA has
developed health criteria documents
which summarize the available
toxicology data for brominated THMs
(USEPA 2005b), brominated HAAs
(USEPA 2005c), MX (USEPA 2000b),
MCAA (USEPA 2005d), and TCAA
(USEPA 2005e). The 2003 IRIS
assessment of DCAA (USEPA 2003b)
and an addendum (USEPA 2005k) also
provides analysis released after Stage 1.
It summarizes information on exposure
from drinking water and develops a
slope factor for DCAA. IRIS also has
toxicological reviews for chloroform
(USEPA 2001a), chlorine dioxide and
chlorite (USEPA 2000c), and bromate
(USEPA 2001b), and is currently
reassessing TCAA.
Slope factors and risk concentrations
for BDCM, bromoform, DBCM and
DCAA have been developed and are
listed in Table II.D–2. For BDCM,
bromoform, and DBCM, table values are
derived from the brominated THM
criteria document (USEPA 2005b),
which uses IRIS numbers that have been
updated using the 1999 EPA Proposed
Guidelines for Carcinogenic Risk
Assessment (USEPA 1999a). For DCAA,
the values are derived directly from
IRIS.
TABLE II.D–2.—QUANTIFICATION OF CANCER RISK
LED 10a
Disinfection byproduct
Slope
factor
(mg/kg/day)¥1
Bromodichloromethane ....................................................................
Bromoform .......................................................................................
Dibromochloromethane ....................................................................
Dichloroacetic Acid ..........................................................................
ED 10a
10 ¥6 Risk
concentration
(mg/L)
0.034
0.0045
0.04
0.048
Slope
factor
(mg/kg/day) ¥1
0.001
0.008
0.0009
0.0007
0.022
0.0034
0.017
0.015 b
10 ¥6 Risk
concentration
(mg/L)
0.002
0.01
0.002
0.0023 b
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a LED
10 is the lower 95% confidence bound on the (effective dose) ED10 value. ED10 is the estimated dose producing effects in 10% of animals.
b The ED
10 risk factors for DCAA have been changed from those given in the comparable table in the proposed Stage 2 DBPR to correct for
transcriptional errors.
More research on DBPs is underway
at EPA and other research institutions.
Summaries of on-going studies may be
found on EPA’s DRINK Web site (https://
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www.epa.gov/safewater/drink/
intro.html). Two-year bioassays by the
National Toxicology Program (NTP)
released in abstract form have recently
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been completed on BDCM and chlorate.
The draft abstract on BDCM reported no
evidence of carcinogenicity when
BDCM was administered via drinking
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water (NTP 2005a). Another recent
study, a modified two-year bioassay on
BDCM in the drinking water, reported
little evidence of carcinogenicity
(George et al. 2002). In a previous NTP
study, tumors were observed, including
an increased incidence of kidney, liver,
and colon tumors, when BDCM was
administered at higher doses by gavage
in corn oil (NTP 1987). EPA will
examine new information on BDCM as
it becomes available. In the chlorate
draft abstract, NTP found some evidence
that it may be a carcinogen (NTP 2004).
Chlorate is a byproduct of hypochlorite
and chlorine dioxide systems. A longterm, two-year bioassay NTP study on
DBA is also complete but has not yet
undergone peer review (NTP 2005b).
b. Reproductive and developmental
health effects. Both human
epidemiology studies and animal
toxicology studies have examined
associations between chlorinated
drinking water or DBPs and
reproductive and developmental health
effects. Based on an evaluation of the
available science, EPA believes the data
suggest that exposure to DBPs is a
potential reproductive and
developmental health hazard.
The following section briefly
discusses the reproductive and
developmental epidemiology and
toxicology information available to EPA.
Further discussion of these studies and
EPA’s conclusions can be found in the
proposed Stage 2 DBPR (USEPA 2003a)
and the Economic Analysis (USEPA
2005a).
i. Epidemiology. As discussed
previously, epidemiology studies have
the strength of relating human exposure
to DBP mixtures through multiple
intake routes. Although the critical
exposure window for reproductive and
developmental effects is much smaller
than that for cancer (generally weeks
versus years), exposure assessment is
also a main limitation of reproductive
and developmental epidemiology
studies. Exposure assessment
uncertainties arise from limited data on
DBP concentrations and maternal water
usage and source over the course of the
pregnancy. However, classification
errors typically push the true risk
estimate towards the null value (Vineis
2004). According to Bove et al. (2002),
‘‘Difficulties in assessing exposure may
result in exposure misclassification
biases that would most likely produce
substantial underestimates of risk as
well as distorted or attenuated
exposure-response trends.’’ Studies of
rare outcomes (e.g., individual birth
defects) often have limited statistical
power because of the small number of
cases being examined. This limits the
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ability to detect statistically significant
associations for small to moderate
relative risk estimates. Small sample
sizes also result in imprecision around
risk estimates reflected by wide
confidence intervals. In addition to the
limitations of individual studies,
evaluating reproductive and
developmental epidemiology studies
collectively is difficult because of the
methodological differences between
studies and the wide variety of
endpoints examined. These factors may
contribute to inconsistencies in the
scientific body of literature as noted
below.
More recent studies tend to be of
higher quality because of improved
exposure assessments and other
methodological advancements. For
example, studies that use THM levels to
estimate exposure tend to be higher
quality than studies that define
exposure by source or treatment. These
factors were taken into account by EPA
when comparing and making
conclusions on the reproductive and
developmental epidemiology literature.
What follows is a summary of available
epidemiology literature on reproductive
and developmental endpoints such as
spontaneous abortion, stillbirth, neural
tube and other birth defects, low birth
weight, and intrauterine growth
retardation. Information is grouped,
where appropriate, into three categories
on fetal growth, viability, and
malformations, and reviews are
described separately afterward. Table
II.D–3 provides a more detailed
description of each study or review.
Fetal growth. Many studies looked for
an association between fetal growth
(mainly small for gestational age, low
birth weight, and pre-term delivery) and
chlorinated water or DBPs. The results
from the collection of studies as a whole
are inconsistent. A number of studies
support the possibility that exposure to
chlorinated water or DBPs are
associated with adverse fetal growth
effects (Infante-Rivard 2004; Wright et
¨ ´
al. 2004; Wright et al. 2003; Kallen and
Robert 2000; Gallagher et al. 1998;
Kanitz et al. 1996; Bove et al. 1995;
Kramer et al. 1992). Other studies
showed mixed results (Porter et al.
2005; Savitz et al. 2005; Yang 2004) or
did not provide evidence of an
association (Toledano et al. 2005;
Jaakkola et al. 2001; Dodds et al. 1999;
Savitz et al. 1995) between DBP
exposure and fetal growth. EPA notes
that recent, higher quality studies
provide some evidence of an increased
risk of small for gestational age and low
birth weight.
Fetal viability. While the database of
epidemiology studies for fetal loss
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399
endpoints (spontaneous abortion or
stillbirth) remains inconsistent as a
whole, there is suggestive evidence of
an association between fetal loss and
chlorinated water or DBP exposure.
Various studies support the possibility
that exposure to chlorinated water or
DBPs is associated with decreased fetal
viability (Toledano et al. 2005; Dodds et
al. 2004; King et al. 2000b; Dodds et al.
1999; Waller et al. 1998; Aschengrau et
al. 1993; Aschengrau et al. 1989). Other
studies did not support an association
(Bove et al. 1995) or reported
inconclusive results (Savitz et al. 2005;
Swan et al. 1998; Savitz et al. 1995)
between fetal viability and exposure to
THMs or tapwater. A recent study by
King et al. (2005) found little evidence
of an association between stillbirths and
haloacetic acids after controlling for
trihalomethane exposures, though nonstatistically significant increases in
stillbirths were seen across various
exposure levels.
Fetal malformations. A number of
epidemiology studies have examined
the relationship between fetal
malformations (such as neural tube, oral
cleft, cardiac, or urinary defects, and
chromosomal abnormalities) and
chlorinated water or DBPs. It is difficult
to assess fetal malformations in
aggregate due to inconsistent findings
and disparate endpoints being examined
in the available studies. Some studies
support the possibility that exposure to
chlorinated water or DBPs is associated
with various fetal malformations
(Cedergren et al. 2002; Hwang et al.
2002; Dodds and King 2001; Klotz and
Pyrch 1999; Bove et al. 1995;
Aschengrau et al. 1993). Other studies
found little evidence (Shaw et al. 2003;
¨ ´
Kallen and Robert 2000; Dodds et al.
1999; Shaw et al. 1991) or inconclusive
results (Magnus et al. 1999) between
chlorinated water or DBP exposure and
fetal malformations. Birth defects most
consistently identified as being
associated with DBPs include neural
tube defects and urinary tract
malformations.
Other endpoints have also been
examined in recent epidemiology
studies. One study suggests an
association between DBPs and
decreased menstrual cycle length
(Windham et al. 2003), which, if
corroborated, could be linked to the
biological basis of other reproductive
endpoints observed. No association
between THM exposure and semen
quality was found (Fenster et al. 2003).
More work is needed in both areas to
support these results.
Reviews. An early review supported
an association between measures of fetal
viability and tap water (Swan et al.
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1992). Three other reviews found data
inadequate to support an association
between reproductive and
developmental health effects and THM
exposure (Reif et al. 1996; Craun 1998;
WHO 2000). Mills et al. (1998)
examined data on and found support for
an association between fetal viability
and malformations and THMs. Another
review presented to the Stage 2 MDBP
FACA found some evidence for an
association with fetal viability and some
fetal malformations and exposure to
DBPs but reported that the evidence was
inconsistent for these endpoints as well
as for fetal growth (Reif et al. 2000). Reif
et al. (2000) concluded that the weight
of evidence from epidemiology studies
suggests that ‘‘DBPs are likely to be
reproductive toxicants in humans under
appropriate exposure conditions,’’ but
from a risk assessment perspective, data
are primarily at the hazard
identification stage. Nieuwenhuijsen et
al. (2000) found some evidence for an
association between fetal growth and
THM exposure and concluded evidence
for associations with other fetal
endpoints is weak but gaining weight. A
qualitative review by Villanueva et al.
(2001) found evidence generally
supports a possible association between
reproductive effects and drinking
chlorinated water. Graves et al. (2001)
supports a possible association for fetal
growth but not fetal viability or
malformations. More recently, Bove et
al. (2002) examined and supported an
association between small for
gestational age, neural tube defects and
spontaneous abortion endpoints and
DBPs. Following a meta-analysis on five
malformation studies, Hwang and
Jaakkola (2003) concluded that there
was evidence which supported
associations between DBPs and risk of
birth defects, especially neural tube
defects and urinary tract defects.
TABLE II.D–3.—SUMMARY OF REPRODUCTIVE/DEVELOPMENTAL EPIDEMIOLOGY STUDIES
Study type
Exposure(s) studied
Porter et al.
2005.
Cross-sectional study in
Maryland, 1998–2002.
Estimated THM and
HAA exposure during
pregnancy.
Intrauterine growth retardation.
Savitz et al.
2005.
Population-based prospective cohort study
in three communities
around the U.S.,
2000–2004.
Estimated TTHM, HAA9,
and TOC exposures
during pregnancy. Indices examined included concentration,
ingested amount, exposure from showering and bathing,
and an integration of
all exposures combined.
Early and late pregnancy loss, preterm
birth, small for gestational age, and term
birth weight.
Toledano et
al. 2005.
Large cross-sectional
study in England,
1992–1998.
Linked mother’s residence at time of delivery to modeled estimates of TTHM levels
in water zones.
Stillbirth, low birth
weight.
Dodds et al.
2004 (and
King et al.
2005).
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Author(s)
Population-based casecontrol study in Nova
Scotia and Eastern
Ontario, 1999–2001.
Estimated THM and
HAA exposure at residence during pregnancy. Linked water
consumption and
showering/bathing to
THM exposure.
Stillbirth .........................
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Outcome(s) measured
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Findings
No consistent association or dose-response relationship was found between exposure to either
TTHM or HAA5 and intrauterine growth retardation. Results suggest an increased risk of
intrauterine growth retardation associated with
TTHM and HAA5 exposure in the third trimester, although only HAA5 results were statistically significant.
No association with pregnancy loss was seen
when looking at high exposure of TTHM compared to low exposure of TTHM. When examining individual THMs, a statistically significant
association
was
found
between
bromodichloromethane (BDCM) and pregnancy loss. A similar, non-statistically significant
association
was
seen
between
dibromochloromethane (DBCM) and pregnancy loss. Some increased risk was seen for
losses at greater than 12 weeks’ gestation for
TTHM, BDCM, and TOX (total organic halide),
but most results generally did not provide support for an association. Preterm birth showed
a small inverse relationship with DBP exposure (i.e. higher exposures showed less
preterm births), but this association was weak.
TTHM exposure of 80 ug/L was associated
with twice the risk for small for gestational age
during the third trimester and was statistically
significant.
A significant association between TTHM and risk
of stillbirth, low birth weight, and very low birth
weight was observed in one of the three regions. When all three regions were combined,
small, but non-significant, excess risks were
found between all three outcomes and TTHM
and chloroform. No associations were observed between reproductive risks and BDCM
or total brominated THMs.
A statistically significant association was observed between stillbirths and exposure to
total THM, BDCM, and chloroform. Associations were also detected for metrics, which incorporated water consumption, showering and
bathing habits. Elevated relative risks were observed for intermediate exposures for total
HAA and DCAA measures; TCAA and
brominated HAA exposures showed no association. No statistically significant associations
or dose-response relationships between any
HAAs and stillbirth were detected after controlling for THM exposure.
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401
TABLE II.D–3.—SUMMARY OF REPRODUCTIVE/DEVELOPMENTAL EPIDEMIOLOGY STUDIES—Continued
Author(s)
Study type
Exposure(s) studied
Outcome(s) measured
InfanteRivard
2004.
Case-control study of
newborns in Montreal,
1998–2000.
Estimated THM levels
and water consumption during pregnancy.
Exposure from showering and presence of
two genetic
polymorphisms.
Intrauterine growth retardation.
Wright et al.
2004.
Large cross-sectional
study: Massachusetts,
1995–1998.
Estimated maternal
third-trimester exposures to TTHMs, chloroform, BDCM, total
HAAs, DCA, TCA, MX
and mutagenicity in
drinking water.
Birth weight, small for
gestational age,
preterm delivery, gestational age.
Yang et al.
2004 (and
Yang et
al. 2000).
Large cross-sectional
studies in Taiwan,
1994–1996.
Compared maternal
consumption of
chlorinated drinking
water (yes/no).
Low birth weight,
preterm delivery.
Fenster et
al. 2003.
Small prospective study
in California, 1990–
1991.
Examined TTHM levels
within the 90 days
preceding semen collection.
Sperm motility, sperm
morphology.
Shaw et al.
2003.
2 case-control maternal
interview studies: CA,
1987–1991.
Neural tube defects, oral
clefts, selected heart
defects.
Windham et
al. 2003.
Prospective study: CA,
1990–1991.
Estimated THM levels
for mothers’ residences from before
conception through
early pregnancy.
Estimated exposure to
THMs through showering and ingestion
over average of 5.6
menstrual cycles per
woman.
Wright et al.
2003.
Cross-sectional study:
Massachusetts, 1990.
Menstrual cycle, follicular phase length
(in days).
Estimated TTHM expoBirth weight, small for
sure in women during
gestational age,
pregnancy (average
preterm delivery, gesfor pregnancy and
tational age.
during each trimester).
Examined maternal
periconceptional DBP
levels and used GIS
to assign water supplies.
Cardiac defects .............
Hwang et al.
2002.
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Cedergren
Retrospective case-conet al. 2002.
trol study: Sweden,
1982–1997.
Compared exposure to
chlorination (yes/no)
and water color levels
for mother’s residence
during pregnancy.
Birth defects (neural
tube defects, cardiac,
respiratory system,
oral cleft, urinary
tract).
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Large cross-sectional
study in Norway,
1993–1998.
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Findings
No associations were found between exposure
to THMs and intrauterine growth retardation.
However, a significant effect was observed between THM exposure and intrauterine growth
retardation for newborns with the CYP2E1
gene variant. Findings suggest that exposure
to THMs at the highest levels can affect fetal
growth but only in genetically susceptible
newborns.
Statistically significant reductions in mean birth
weight were observed for BDCM, chloroform,
and mutagenic activity. An exposure-response
relationship was found between THM exposure and reductions in mean birth weight and
risk of small for gestational age. There was no
association between preterm delivery and elevated levels of HAAs, MX, or mutagenicity. A
reduced risk of preterm delivery was observed
with high THM exposures. Gestational age
was associated with exposure to THMs and
mutagenicity.
Residence in area supplied with chlorinated
drinking water showed a statistically significant
association with preterm delivery. No association was seen between chlorinated drinking
water and low birth weight.
No association between TTHM level and sperm
mobility or morphology. BDCM was inversely
associated with linearity of sperm motion.
There was some suggestion that water consumption and other ingestion metrics may be
associated with different indicators of semen
quality.
No associations or exposure-response relation
were observed between malformations and
TTHMs in either study.
Findings suggest that THM exposure may affect
ovarian function. All brominated THM compounds were associated with significantly
shorter menstrual cycles with the strongest
finding for chlorodibromomethane. There was
little association between TTHM exposure and
luteal phase length, menses length, or cycle
variability.
Statistically significant associations between 2nd
trimester and pregnancy average TTHM exposure and small for gestational age and fetal
birth weight were detected. Small, statistically
significant increases in gestational duration/
age were observed at increased TTHM levels,
but there was little evidence of an association
between TTHM and preterm delivery or low
birth weight.
Exposure to chlorine dioxide in drinking water
showed statistical significance for cardiac defects. THM concentrations of 10 ug/L and
higher were significantly associated with cardiac defects. No excess risk for cardiac defect
and nitrate were seen.
Risk of any birth defect, cardiac, respiratory system, and urinary tract defects were significantly associated with water chlorination. Exposure to chlorinated drinking water was statistically significantly associated with risk of
ventricular septal defects, and an exposure-response pattern was seen. No other specific
defects were associated with the exposures
that were examined.
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TABLE II.D–3.—SUMMARY OF REPRODUCTIVE/DEVELOPMENTAL EPIDEMIOLOGY STUDIES—Continued
Study type
Exposure(s) studied
Dodds and
King 2001.
Population-based retrospective cohort in
Nova Scotia, 1988–
1995.
Estimated THM, chloroform, and
bromodichloromethane (BDCM) exposure.
Neural tube defects,
cardiovascular defects, cleft defects,
chromosomal abnormalities.
Jaakkola et
al. 2001.
Large cross-sectional
study in Norway,
1993–1995.
Compared chlorination
(yes/no) and water
color (high/low) for
mother during pregnancy.
Low birth weight, small
for gestational age,
preterm delivery.
¨ ´
Kallen and
Robert
2000.
Large cross-sectional
cohort study in Sweden, 1985–1994.
Linked prenatal exposure to drinking water
disinfected with various methods (no
chlorine, chlorine dioxide only, sodium
hypochlorite only).
Gestational duration,
birth weight, intrauterine growth, mortality, congenital malformations, and other
birth outcomes.
Dodds et al.
1999 (and
King et al.
2000b).
Population-based retrospective cohort study
in Nova Scotia, 1988–
1995.
Estimated TTHM level
for women during
pregnancy.
Low birth weight,
preterm birth, small
for gestational age,
stillbirth, chromosomal
abnormalities, neural
tube defects, cleft defects, major cardiac
defects.
Klotz and
Pyrch
1999 (and
Klotz and
Pyrch
1998).
Magnus et
al. 1999.
Population-based casecontrol study in New
Jersey, 1993–1994.
Estimated exposure of
pregnant mothers to
TTHMs and HAAs,
and compared source
of water.
Neural tube defects ......
Large cross-sectional
study in Norway,
1993–1995.
Compared chlorination
(yes/no) and water
color (high/low) at
mothers’ residences
at time of birth.
Birth defects (neural
tube defects, major
cardiac, respiratory,
urinary, oral cleft).
Gallagher et
al. 1998.
Retrospective cohort
study of newborns in
Colorado, 1990–1993.
Estimated THM levels in
drinking water during
third trimester of pregnancy.
Low birth weight, term
low birthweight, and
preterm delivery.
Swan et al.
1998.
wwhite on PROD1PC65 with RULES2
Author(s)
Prospective study in
Compared consumption
California, 1990–1991.
of cold tap water to
bottled water during
early pregnancy.
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Outcome(s) measured
Spontaneous abortion ...
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Findings
Exposure to BDCM was associated with increased risk of neural tube defects, cardiovascular anomalies. Chloroform was not associated with neural tube defects, but was associated with chromosomal abnormalities. No association between THM and cleft defects were
detected.
No evidence found for association between prenatal exposure to chlorinated drinking water
and low birth weight or small for gestational
age. A reduced risk of preterm delivery was
noted for exposure to chlorinated water with
high color content.
A statistically significant difference was found for
short gestational duration and low birth weight
among infants whose mother resided in areas
using sodium hypochlorite, but not for chlorine
dioxide. Sodium hypochlorite was also associated with other indices of fetal development
but not with congenital defects. No other effects were observed for intrauterine growth,
childhood cancer, infant mortality, low Apgar
score, neonatal jaundice, or neonatal
hypothyroidism in relation to either disinfection
method.
A statistically significant increased risk for stillbirths and high total THMs and specific THMs
during pregnancy was detected, with higher
risks observed among asphyxia-related stillbirths. Bromodichloromethane had the strongest association and exhibited an exposure-response pattern. There was limited evidence of
an association between THM level and other
reproductive outcomes. No congenital anomalies were associated with THM exposure, except for a non-statistically significant association with chromosomal abnormalities.
A significant association was seen between exposure to THMs and neural tube defects. No
associations were observed for neural tube
defects
and
haloacetic
acids
or
haloacetonitriles.
Statistically significant associations were seen
between urinary tract defects and chlorination
and high water color (high content of organic
compounds). No associations were detected
for other outcomes or all birth defects combined. A non-statistically significant, overall excess risk of birth defects was seen within municipalities with chlorination and high water
color compared to municipalities with no
chlorination and low color.
Weak, non-statistically significant association
with low birth weight and TTHM exposure during the third trimester. Large statistically significant increase for term low birthweight at
highest THM exposure levels. No association
between preterm delivery and THM exposure.
Pregnant women who drank cold tap water compared to those who consumed no cold tap
water showed a significant finding for spontaneous abortion at one of three sites.
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TABLE II.D–3.—SUMMARY OF REPRODUCTIVE/DEVELOPMENTAL EPIDEMIOLOGY STUDIES—Continued
Author(s)
Study type
Exposure(s) studied
Outcome(s) measured
Findings
Statistically significant increased risk between
high intake of TTHMs and spontaneous abortion compared to low intake. BDCM statistically associated with increased spontaneous
abortion; other THMs not. Reanalysis of exposure yielded less exposure misclassification
and relative risks similar in magnitude to earlier study. An exposure-response relationship
was seen between spontaneous abortion and
ingestion exposure to TTHMs.
Smaller body length and small cranial circumference showed statistical significant association with maternal exposure to chlorinated
drinking water. Neonatal jaundice linked statistically to prenatal exposure to drinking water
treated with chlorine dioxide. Length of pregnancy, type of delivery, and birthweight
showed no association.
Weak, statistically significant increased risk
found for higher TTHM levels with small for
gestational age, neural tube defects, central
nervous system defects, oral cleft defects, and
major cardiac defects. Some association with
higher TTHM exposure and low birth weight.
No effect seen for preterm birth, very low birth
weight, or fetal deaths.
There was a statistically significant increased
miscarriage risk with high THM concentration,
but THM intake (based on concentration times
consumption level) was not related to pregnancy outcome. No associations were seen for
preterm delivery or low birth weight. Water
source was not related to pregnancy outcome
either, with the exception of a non-significant,
increased risk of spontaneous abortion for bottled water users. There was a non-statistically
significant pattern of reduced risk with increased consumption of water for all three outcomes.
There was a non-significant, increased association between frequency of stillbirths and maternal
exposure
to
chlorinated
versus
chloraminated surface water. An increased risk
of urinary track and respiratory track defects
and chlorinated water was detected. Neonatal
death and other major malformations showed
no association. No increased risk seen for any
adverse pregnancy outcomes for surface
water versus ground and mixed water use.
Statistically significant increased risk for intrauterine growth retardation effects from chloroform exposure were observed. Non-significant
increased risks were observed for low birth
weight and chloroform and for intrauterine
growth retardation and DCBM. No intrauterine
growth retardation or low birth weight effects
were seen for the other THMs, and no effects
on prematurity were observed for any of the
THMs.
Following reanalysis, no association between
cardiac anomalies and TTHM level were observed.
Prospective cohort in
Estimated TTHM levels
California, 1989–1991.
during first trimester
of pregnancy via ingestion and showering.
Spontaneous abortion ...
Kanitz et al.
1996.
Cross-sectional study in
Italy, 1988–1989.
Compared 3 types of
water treatment (chlorine dioxide, sodium
hypochlorite, and
chlorine dioxide/sodium hypochlorite).
Low birth weight, body
length, cranial circumference, preterm delivery, and other effects.
Bove et al.
1995 (and
Bove et
al. 1992a
& 1992b).
Large cohort cross-sectional study in New
Jersey, 1985–1988.
Examined maternal exposure to TTHM and
various other contaminants.
Low birth weight, fetal
deaths, small for gestational age, birth defects (neural tube defects, oral cleft, central nervous system,
major cardiac).
Savitz et al.
1995.
Population-based casecontrol study: North
Carolina, 1988–1991.
Examined TTHM concentration at residences and water
consumption (during
first and third trimesters).
Spontaneous abortion,
preterm delivery, low
birth weight.
Aschengrau
Case-control study in
et al. 1993.
Massachusetts, 1977–
1980.
Source of water and 2
types of water treatment (chlorination,
chloramination).
Neonatal death, stillbirth, congenital
anomalies.
Kramer et
al. 1992.
Population-based casecontrol study in Iowa,
1989–1990.
Examined chloroform,
DCBM, DBCM, and
bromoform levels and
compared type of
water source (surface,
shallow well, deep
well).
Low birth weight, prematurity, intrauterine
growth retardation.
Shaw et al.
1991 (and
Shaw et
al. 1990).
wwhite on PROD1PC65 with RULES2
Waller et al.
1998 (and
Waller et
al. 2001).
Small case-control
study: Santa Clara
County, CA, 1981–
1983.
Estimated chlorinated
tap water consumption, mean maternal
TTHM level, showering/bathing exposure at residence during first trimester.
Source of water and exposure to metals and
other contaminants.
Congenital cardiac
anomalies.
Aschengrau
Case-control study in
et al. 1989.
Massachusetts, 1976–
1978.
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A statistically significantly association was detected between surface water source and frequency of spontaneous abortion.
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TABLE II.D–3.—SUMMARY OF REPRODUCTIVE/DEVELOPMENTAL EPIDEMIOLOGY STUDIES—Continued
Author(s)
Reviews/
Metaanalyses
Hwang and
Jakkola
2003.
Study type
Exposure(s) studied
Outcome(s) measured
Findings
Review and meta-analysis of 5 studies.
Compared DBP levels,
source of water, chlorine residual, color
(high/low), and 2
types of disinfection:
chlorination and
chloramination.
Examined THM levels.
Compared drinking
water source and type
of water treatment.
Birth defects (respiratory
system, urinary system, neural tube defects, cardiac, oral
cleft).
The meta-analysis supports an association between exposure to chlorination by-products
and the risk of any birth defect, particularly the
risk of neural tube defects and urinary system
defects.
Birth defects, small for
gestational age, low
birth weight, preterm
delivery, spontaneous
abortion, fetal death.
Review found the studies of THMs and adverse
birth outcomes provide moderate evidence for
associations with small for gestational age,
neural tube defects, and spontaneous abortions. Authors felt risks may have been underestimated and exposure-response relationships
distorted
due
to
exposure
misclassification.
Weight of evidence suggested positive association with DBP exposure for growth retardation
such as small for gestational age or intrauterine growth retardation and urinary tract defects. Review found no support for DBP exposure and low birth weight, preterm delivery,
some specific birth defects, and neonatal
death, and inconsistent findings for all birth defects, all central nervous system defects, neural tube defects, spontaneous abortion, and
stillbirth.
Review found positive associations between increased spontaneous abortion, low birth
weight, small for gestational age, and neural
tube defects and drinking chlorinated water in
most studies, although not always with statistical significance.
Qualitative review of 14
studies.
Graves et al.
2001.
Review of toxicological
and epidemiological
studies using a weight
of evidence approach.
Examined water consumption, duration of
exposure, THM levels,
HAA levels, and other
contaminants. Compared source of
water, water treatment, water color
(high/low), etc.
Low birth weight,
preterm delivery,
small for gestational
age, intrauterine
growth retardation,
specific birth defects,
neonatal death, decreased fertility, fetal
resorption, and other
effects.
Villanueva et
al. 2001.
Qualitative review of 14
reproductive and developmental health effect studies.
Qualitative review of numerous toxicological
and epidemiological
studies.
Reif et al.
2000.
Qualitative reviews of
numerous epidemiological studies.
Compared exposure to
TTHM levels, mutagenic drinking water,
water consumption,
source water, types of
disinfection
(chlorination and
chloramination), and
residence times.
Examined levels of various DBPs, water consumption, and duration of exposure.
Compared water
color, water treatment,
source of water, etc.
Compared source of
water supply and
methods of disinfection. Estimated TTHM
levels.
Spontaneous abortion,
low birth weight, small
for gestational age,
neural tube defects,
other reproductive
and developmental
outcomes.
Nieuwenhuijsen et al.
2000.
WHO 2000
Qualitative reviews of
various studies in Finland, U.S., and Canada.
Various exposures to
THMs.
Craun, ed.
1998.
wwhite on PROD1PC65 with RULES2
Bove et al.
2002.
Qualitative review of 10
studies, focus on California cohort study.
Examined THM levels
and water consumption, and compared
source of water and
water treatment (chlorine, chloramines,
chlorine dioxide).
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Low birth weight,
preterm delivery,
spontaneous abortions, stillbirth, birth
defects, etc.
Birth weight, low birth
weight, intrauterine
growth retardation,
small for gestational
age, preterm deliver,
somatic parameters,
neonatal jaundice,
spontaneous abortion,
stillbirth, developmental anomalies.
Various reproductive
and developmental effects.
Stillbirth, neonatal
death, spontaneous
abortion, low birth
weight, preterm delivery, intrauterine
growth retardation,
neonatal jaundice,
birth defects.
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The review supports some evidence of association between THMs and low birth weight, but
inconclusive. Review found no evidence of association between THMs and preterm delivery,
and that associations for other outcomes
(spontaneous abortions, stillbirth, and birth defects) were weak but gaining weight.
Weight of evidence suggested DBPs are reproductive toxicants in humans under appropriate
exposure conditions. The review reports findings between TTHMs and effects on fetal
growth, fetal viability, and congenital anomalies as inconsistent. Reviewers felt data are at
the stage of hazard identification and did not
suggest a dose-response pattern of increasing
risk with increasing TTHM concentration.
Review found some support for an association
between increased risks of neural tube defects
and miscarriage and THM exposure. Other associations have been observed, but the authors believed insufficient data exist to assess
any of these associations.
Associations between DBPs and various reproductive effects were seen in some epidemiological studies, but the authors felt these results do not provide convincing evidence for a
causal relationship between DBPs and reproductive effects.
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TABLE II.D–3.—SUMMARY OF REPRODUCTIVE/DEVELOPMENTAL EPIDEMIOLOGY STUDIES—Continued
Study type
Exposure(s) studied
Outcome(s) measured
Findings
Mills et al.
1998.
Qualitative review of 22
studies.
Review found studies suggest possible increases
in adverse reproductive and developmental effects, such as increased spontaneous abortion
rates, small for gestational age, and fetal
anomalies, but that insufficient evidence exists
to establish a causal relationship.
Review of 3 case-control studies and 1
cross-sectional study.
Examined TTHM levels
and water consumption. Compared
source of water and 2
types of water treatment (chlorination and
chloramination).
Examined THM levels at
residences, dose consumption, chloroform.
Compared source of
waters and 2 types of
water treatment
(chlorination and
chloramination).
Various reproductive
and developmental effects.
Reif et al.
1996.
Qualitative review of 5
studies in Santa Clara
County, CA (Deane et
al. 1992, Wrensch et
al. 1992, HertzPicciotto et al. 1992,
Windham et al. 1992,
Fenster et al. 1992).
Birth defects (central
nervous system, neural tube defects, cardiac, oral cleft, respiratory, urinary tract),
spontaneous abortion,
low birth weight,
growth retardation,
preterm delivery,
intrauterine growth retardation, stillbirth,
neonatal death.
Spontaneous abortion ...
Studies reviewed suggest that exposure to DBPs
may increase intrauterine growth retardation,
neural tube defects, major heart defects, and
oral cleft defects. Review found epidemiologic
evidence supporting associations between exposure to DBPs and adverse pregnancy outcomes to be sparse and to provide an inadequate basis to identify DBPs as a reproductive or developmental hazard.
Swan et al.
1992.
wwhite on PROD1PC65 with RULES2
Author(s)
Compared maternal
consumption of residence tap water to
bottled water.
ii. Toxicology. To date, the majority of
reproductive and developmental
toxicology studies have been short term
and higher dose. Many of these studies
are summarized in a review by Tyl
(2000). A summary of this review and of
additional studies is provided in the
proposed Stage 2 DBPR (USEPA 2003a).
Individual DBP supporting documents
evaluate and assess additional studies as
well (USEPA 2000b; USEPA 2000c;
USEPA 2001a; USEPA 2001b; USEPA
2003b; USEPA 2005b; USEPA 2005c;
USEPA 2005d; USEPA 2005e; USEPA
2005k). A number of recent studies have
been published that include in vivo and
in vitro assays to address mechanism of
action. Overall, reproductive and
developmental toxicology studies
indicate a possible reproductive/
developmental health hazard although
they are preliminary in nature for the
majority of DBPs, and the dose-response
characteristics of most DBPs have not
been quantified. Some of the
reproductive effects of DCAA were
quantified as part of the RfD
development process, and impacts of
DCAA on testicular structure are one of
the critical effects in the study that is
the basis of the RfD (USEPA 2003b).
A few long term, lower dose studies
have been completed. Christian et al.
(2002a and 2002b) looked for an
association between BDCM and DBAA
and reproductive and developmental
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endpoints. The authors identified a
NOAEL and LOAEL of 50 ppm and 150
ppm, respectively, based on delayed
sexual maturation for BDCM and a
NOAEL and LOAEL of 50 ppm and 250
ppm based on abnormal
spermatogenesis for DBAA. The authors
concluded that similar effects in
humans would only be seen at levels
many orders of magnitude higher than
that of current drinking water levels. As
discussed in more detail in the
proposal, EPA believes that because of
key methodological differences
indicated as being important in other
studies (Bielmeier et al. 2001; Bielmeier
et al. 2004; Kaydos et al. 2004;
Klinefelter et al. 2001; Klinefelter et al.
2004), definitive conclusions regarding
BDCM and DBAA cannot be drawn.
Other multi-generation research
underway includes a study on BCAA,
but this research is not yet published.
Biological plausibility for the effects
observed in reproductive and
developmental epidemiological studies
has been demonstrated through various
toxicological studies on some individual
DBPs (e.g., Bielmeier et al. 2001;
Bielmeier et al. 2004; Narotsky et al.
1992; Chen et al. 2003; Chen et al.
2004). Some of these studies were
conducted at high doses, but similarity
of effects observed between toxicology
studies and epidemiology studies
strengthens the weight of evidence for a
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Four of the studies reviewed suggest that
women drinking bottled water during the first
trimester of pregnancy may have reduced risk
of spontaneous abortion relative to drinking
tap water. No association seen in the fifth
study. Review concluded that if findings are
causal and not due to chance or bias, data
suggest a 10–50% increase in spontaneous
abortion risk for pregnant women drinking tap
water over bottled water.
possible association between adverse
reproductive and developmental health
effects and exposure to chlorinated
surface water.
c. Conclusions. EPA’s weight of
evidence evaluation of the best available
science on carcinogenicity and
reproductive and developmental effects,
in conjunction with the widespread
exposure to DBPs, supports the
incremental regulatory changes in
today’s rule that target lowering DBPs
and providing equitable public health
protection.
EPA believes that the cancer
epidemiology and toxicology literature
provide important information that
contributes to the weight of evidence for
potential health risks from exposure to
chlorinated drinking water. At this time,
the cancer epidemiology studies support
a potential association between
exposure to chlorinated drinking water
and cancer, but evidence is insufficient
to establish a causal relationship. The
epidemiological evidence for an
association between DBP exposure and
colon and rectal cancers is not as
consistent as it is for bladder cancer,
although similarity of effects reported in
animal toxicity and human
epidemiology studies strengthens the
evidence for an association with colon
and rectal cancers. EPA believes that the
overall cancer epidemiology and
toxicology data support the decision to
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pursue additional DBP control measures
as reflected in the Stage 2 DBPR.
Based on the weight of evidence
evaluation of the reproductive and
developmental epidemiology data, EPA
concludes that a causal link between
adverse reproductive or developmental
health effects and exposure to
chlorinated drinking water or DBPs has
not been established, but that there is a
potential association. Despite
inconsistent findings across studies,
some recent studies continue to suggest
associations between DBP exposure and
various adverse reproductive and
developmental effects. In addition, data
from a number of toxicology studies,
although the majority of them were
conducted using high doses,
demonstrate biological plausibility for
some of the effects observed in
epidemiology studies. EPA concludes
that no dose-response relationship or
causal link has been established
between exposure to chlorinated
drinking water or disinfection
byproducts and adverse developmental
or reproductive health effects. EPA’s
evaluation of the best available studies,
particularly epidemiology studies is that
they do not support a conclusion at this
time as to whether exposure to
chlorinated drinking water or
disinfection byproducts causes adverse
developmental and reproductive health
effects, but do provide an indication of
a potential health concern that warrants
incremental regulatory action beyond
the Stage 1 DBPR.
wwhite on PROD1PC65 with RULES2
D. DBP Occurrence and DBP Control
New information on the occurrence of
DBPs in distribution systems raises
issues about the protection provided by
the Stage 1 DBPR. This section presents
new occurrence and treatment
information used to identify key issues
and to support the development of the
Stage 2 DBPR. For a more detailed
discussion see the proposed Stage 2
DBPR (USEPA 2003a). For additional
information on occurrence of regulated
and nonregulated DBPs, see the
Occurrence Assessment for the Final
Stage 2 Disinfectants and Disinfection
Byproducts Rule (USEPA 2005f).
1. Occurrence
EPA, along with the M-DBP Advisory
Committee, collected, developed, and
evaluated new information that became
available after the Stage 1 DBPR was
published. The Information Collection
Rule (ICR) (USEPA 1996) provided new
field data on DBP exposure for large
water systems and new study data on
the effectiveness of several DBP control
technologies. The unprecedented
amount of information collected under
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the ICR was supplemented by a survey
conducted by the National Rural Water
Association, data provided by various
States, the Water Utility Database
(which contains data collected by the
American Water Works Association),
and ICR Supplemental Surveys for small
and medium water systems.
After analyzing the DBP occurrence
data, EPA and the Advisory Committee
reached three significant conclusions
that in part led the Advisory Committee
to recommend further control of DBPs
in public water systems. First, the data
from the Information Collection Rule
showed that the RAA compliance
calculation under the Stage 1 DBPR
allows elevated TTHM or HAA5 levels
to regularly occur at some locations in
the distribution system while the overall
average of TTHM or HAA5 levels at all
DBP monitoring locations is below the
MCLs of the Stage 1 DBPR. Customers
served at those sampling locations with
DBP levels that are regularly above
0.080 mg/L TTHM and 0.060 mg/L
HAA5 experience higher exposure
compared to customers served at
locations where these levels are
consistently met.
Second, the new data demonstrated
that DBP levels in single samples can be
substantially above 0.080 mg/L TTHM
and 0.060 mg/L HAA5. Some customers
receive drinking water with
concentrations of TTHM and HAA5 up
to 75% above 0.080 mg/L and 0.060 mg/
L, respectively, even when their water
system is in compliance with the Stage
1 DBPR. Some studies support an
association between acute exposure to
DBPs and potential adverse
reproductive and developmental health
effects (see Section III.C for more detail).
Third, the data from the Information
Collection Rule revealed that the highest
TTHM and HAA5 levels can occur at
any monitoring site in the distribution
system. In fact, the highest
concentrations did not occur at the
maximum residence time locations in
more than 50% of all ICR samples. The
fact that the locations with the highest
DBP levels vary in different public
water systems indicates that the Stage 1
DBPR monitoring may not accurately
represent the high DBP concentrations
that actually exist in distribution
systems, and that additional monitoring
is needed to identify distribution system
locations with elevated DBP levels.
These data showed that efforts beyond
the Stage 1 DBPR are needed to provide
more equitable protection from DBP
exposure across the entire distribution
system. The incremental regulatory
changes made under the Stage 2 DBPR
meet this need by reevaluating the
locations of DBP monitoring sites and
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addressing high DBP concentrations that
occur at particular locations or in single
samples within systems in compliance.
2. Treatment
The analysis of the new treatment
study data confirmed that certain
technologies are effective at reducing
DBP concentrations. Bench- and pilotscale studies for granular activated
carbon (GAC) and membrane
technologies required by the
Information Collection Rule provided
information on the effectiveness of the
two technologies. Other studies found
UV light to be highly effective for
inactivating Cryptosporidium and
Giardia at low doses without promoting
the formation of DBPs (Malley et al.
1996; Zheng et al. 1999). This new
treatment information adds to the
treatment options available to utilities
for controlling DBPs beyond the
requirements of the Stage 1 DBPR.
E. Conclusions for Regulatory Action
After extensive analysis of available
data and rule options considered by the
Advisory Committee and review of
public comments on the proposed Stage
2 DBPR (USEPA, 2003a), EPA is
finalizing a Stage 2 DBPR control
strategy consistent with the key
elements of the Agreement in Principle
signed in September 2000 by the
participants in the Stage 2 M–DBP
Advisory Committee. EPA believes that
exposure to chlorinated drinking water
may be associated with cancer,
reproductive, and developmental health
risks. EPA determined that the risktargeting measures recommended in the
Agreement in Principle will require
only those systems with the greatest risk
to make treatment and operational
changes and will maintain simultaneous
protection from potential health
concerns from DBPs and microbial
contaminants. EPA has carefully
evaluated and expanded upon the
recommendations of the Advisory
Committee and public comments to
develop today’s rule. EPA also made
simplifications where possible to
minimize complications for public
water systems as they transition to
compliance with the Stage 2 DBPR
while expanding public health
protection. The requirements of the
Stage 2 DBPR are described in detail in
Section IV of this preamble.
IV. Explanation of Today’s Action
A. MCLGs
MCLGs are set at concentration levels
at which no known or anticipated
adverse health effects occur, allowing
for an adequate margin of safety.
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1. Chloroform MCLG
a. Today’s rule. The final MCLG for
chloroform is 0.07 mg/L. The MCLG was
calculated using toxicological evidence
that the carcinogenic effects of
chloroform are due to sustained tissue
toxicity. EPA is not changing the other
THM MCLGs finalized in the Stage 1
DBPR.
b. Background and analysis. The
MCLG for chloroform is unchanged
from the proposal. The MCLG is
calculated using a reference dose (RfD)
MCLG for Chloroform =
carcinogenic to humans under
conditions that do not cause
cytotoxicity and cell regeneration
(USEPA 2001a). Therefore, the doseresponse is nonlinear, and the MCLG is
set at 0.07 mg/L. This conclusion has
been reviewed by the SAB (USEPA
2000d), who agree that nonlinear
approach is most appropriate for the
risk assessment of chloroform; it also
remains consistent with the principles
of the 1999 EPA Proposed Guidelines
for Carcinogenic Risk Assessment
(USEPA 1999a) and the final Cancer
Guidelines ( USEPA 2005i), which
allow for nonlinear extrapolation.
EPA also received some comments
requesting a combined MCLG for THMs
or HAAs. This is not appropriate
because these different chemicals have
different health effects.
2. HAA MCLGs: TCAA and MCAA
a. Today’s rule. Today’s rule finalizes
the proposed Stage 2 MCLG for TCAA
of 0.02 mg/L (USEPA 2003a) and sets an
MCLG for MCAA of 0.07 mg/L. EPA is
not changing the other HAA MCLGs
finalized in the Stage 1 DBPR (USEPA
1998a).
b. Background and analysis. The Stage
1 DBPR included an MCLG for TCAA of
0.03 mg/L and did not include an MCLG
for MCAA (USEPA 1998a). Based on
toxicological data published after the
Stage 1 DBPR, EPA proposed new
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MCLG for TCAA =
The chronic bioassay for TCAA by
DeAngelo et al. (1997) was selected as
the critical study for the development of
the RfD. In this chronic drinking water
study, a dose-response was noted for
several endpoints and both a LOAEL
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(0.01 mg/kg /day)(70 kg)(0.2)
= 0.07 mg/L (rounded)
2 L/day
(0.03 mg/kg/day)(70 kg)(0.2)
= 0.02 mg/L (rounded)
(2 L/day)(10)
and NOAEL were determined. The data
are consistent with the findings in both
the Pereira (1996) chronic drinking
water study and the Mather et al. (1990)
subchronic drinking water study. The
RfD of 0.03 mg/kg/day is based on the
PO 00000
MCLGs for TCAA and MCAA of 0.02
mg/L and 0.03 mg/L, respectively, in the
Stage 2 proposal (USEPA 2003a). The
proposed TCAA MCLG and its
supporting analysis is being finalized
unchanged in today’s final rule. The
MCLG calculation for MCAA is revised
in this final rule, based on a new
reference dose, as discussed later. See
the proposed Stage 2 DBPR (USEPA
2003a) for a detailed discussion of the
calculation of the MCLGs.
TCAA. The MCLG for TCAA was
calculated based on the RfD of 0.03 mg/
kg/day using a 70 kg adult body weight,
a 2 L/day drinking water intake, and a
relative source contribution of 20%. An
additional tenfold risk management
factor has been applied to account for
the possible carcinogenicity of TCAA.
This approach is consistent with EPA
policy. TCAA induces liver tumors in
mice (Ferreira-Gonzalez et al. 1995;
Pereira 1996; Pereira and Phelps 1996;
Tao et al. 1996; Latendresse and Pereira
1997; Pereira et al. 1997) but not in rats
(DeAngelo et al. 1997). Much of the
recent data on the carcinogenicity of
TCAA have focused on examining the
carcinogenic mode(s) of action.
However, at this time, neither the
bioassay nor the mechanistic data are
sufficient to support the development of
a slope factor from which to quantify
the cancer risk.
Frm 00021
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NOAEL of 32.5 mg/kg/day for liver
histopathological changes in rats
(DeAngelo et al. 1997). A composite
uncertainty factor of 1000 was applied
in the RfD determination. A default
uncertainty factor of 10 was applied to
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Based on an analysis of the available
scientific data on chloroform, EPA
believes that the chloroform doseresponse is nonlinear and that
chloroform is likely to be carcinogenic
only under high exposure conditions
(USEPA 2001a). This assessment is
supported by the principles of the 1999
EPA Proposed Guidelines for
Carcinogen Risk Assessment (USEPA
1999a) and reconfirmed by the 2005
final Cancer Guidelines (USEPA 2005i).
The science in support of a nonlinear
approach for estimating the
carcinogenicity of chloroform was
affirmed by the Chloroform Risk
Assessment Review Subcommittee of
the EPA SAB Executive Committee
(USEPA 2000d). Since the nonzero
MCLG is based on a mode of action
consideration specific to chloroform, it
does not affect the MCLGs of other
trihalomethanes.
c. Summary of major comments. EPA
received many comments in support of
the proposed MCLG calculation for
chloroform, although some commenters
disagreed with a non-zero MCLG.
At this time, based on an analysis of
all the available scientific data on
chloroform, EPA concludes that
chloroform is likely to be carcinogenic
to humans only under high exposure
conditions that lead to cytotoxicity and
regenerative hyperplasia and that
chloroform is not likely to be
of 0.01 mg/kg/day and an adult tap
water consumption of 2 L per day for a
70 kg adult. A relative source
contribution (RSC) of 20% was used in
accordance with Office of Water’s
current approach for deriving RSC
through consideration of data that
indicate that other routes and sources of
exposure may potentially contribute
substantially to the overall exposure to
chloroform. See the proposed Stage 2
DBPR (USEPA 2003a) for a detailed
discussion of the chloroform MCLG.
ER04JA06.003</MATH>
Establishment of an MCLG for each
specific contaminant is based on the
available evidence of carcinogenicity or
noncancer adverse health effects from
drinking water exposure using EPA’s
guidelines for risk assessment. MCLGs
are developed to ensure they are
protective of the entire population.
Today’s rule provides MCLGs for
chloroform and two haloacetic acids,
monochloroacetic acid (MCAA) and
trichloroacetic acid (TCAA).
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Federal Register / Vol. 71, No. 2 / Wednesday, January 4, 2006 / Rules and Regulations
the RfD to account for extrapolation
from an animal study because data to
quantify rat-to-human differences in
toxicokinetics or toxicodynamics are not
available. The default uncertainty factor
of 10 was used to account for human
variability in the absence of data on
differences in human susceptibility.
Although subchronic and chronic
studies of TCAA have been reported for
multiple species, many studies have
focused on liver lesions and a full
evaluation of a wide range of potential
target organs has not been conducted in
two different species. In addition, there
has been no multi-generation study of
reproductive toxicity and the data from
teratology studies in rats provide
LOAEL values but no NOAEL for
developmental toxicity. Thus, an
additional uncertainty factor of 10 was
used to account for database
insufficiencies.
The MCLG calculation also includes a
relative source contribution (RSC) of
20%. The RSC was derived consistent
with Office of Water’s current approach
for deriving RSC. In addition to
disinfected water, foods are expected to
contribute to daily exposure to TCAA
(Raymer et al. 2001, 2004; Reimann et
al. 1996). Some of the TCAA in foods
comes from cleaning and cooking foods
in chlorinated water. Additional TCAA
is found in some foods because of the
widespread use of chlorine as a
sanitizing agent in the food industry
(USFDA 1994). EPA was not able to
identify any dietary surveys or duplicate
diet studies of TCAA in the diet. TCAA
also has been identified in rain water,
(3.5 mg /kg/day)
= 0.012 mg /kg/day rounded to 0.01 mg /kg/day
(300)
Where:
3.5 mg/kg/day = NOAEL for decreased
body weight plus decreased liver,
kidney and spleen weights in rats
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The RSC for MCAA was selected
using comparable data to that discussed
for TCAA. MCAA, like TCAA, has been
found in foods and is taken up by foods
during cooking (15% in chicken to 62%
in pinto beans) and cleaning (2.5% for
lettuce) with water containing 500 ppb
MCAA (Reimann et al.1996; Raymer et
al. 2001, 2004). Rinsing of cooked foods
20:53 Jan 03, 2006
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extrapolation, inter-individual
variability in humans, and
deficiencies in the database.
exposed to MCA for 104 weeks in
drinking water (DeAngelo et al.
1997).
300 = composite uncertainty factor
chosen to account for inter species
MCLG for MCAA =
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change as a NOAEL. Increased spleen
weights in the absence of
histopathological effects are not
necessarily adverse. In addition, spleen
weights were decreased, rather than
increased in the mid- and high-dose
groups in the DeAngelo et al. (1997)
study and were accompanied by a
significant decrease in body weight,
decreased relative and absolute liver
weights, decreased absolute kidney
weight, and an increase in relative testes
weight. Accordingly, the mid-dose in
this same study (26.1 mg/kg/day) has
been categorized as the LOAEL with the
lower 3.5 mg/kg/day dose as a NOAEL.
Based on a NOAEL of 3.5 mg/kg/day
(DeAngelo et al. 1997), the revised RfD
was calculated as shown below, with a
composite uncertainty factor of 300.
EPA used a default uncertainty factor of
10 to account for extrapolation from an
animal study, since no data on rat-tohuman differences in toxicokinetics or
toxicodynamics were identified. A
default uncertainty factor of 10 was
used to account for human variability in
the absence of data on the variability in
the toxicokinetics of MCAA in humans
or in human susceptibility to MCAA.
An additional uncertainty factor of three
was used to account for database
insufficiencies. Although there is no
multi-generation reproduction study,
the available studies of reproductive
and developmental processes suggest
that developmental toxicity is unlikely
to be the most sensitive endpoint. This
led to the following calculation of the
Reference Dose (RfD) and MCLG for
MCAA:
(0.01 mg/kg/day)(70 kg)(0.2)
= 0.07 mg/L
2 L/day
did not increase the MCAA content of
foods to the same extent as was
observed for TCAA (Raymer et al. 2004).
MCAA was found to be completely
stable in water boiled for 60 minutes
and is likely to be found in the diet due
to the use of chlorinated water in food
preparation and the use of chlorine as
a sanitizing agent by the food industry
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(USFDA 1994). As with TCAA,
inhalation and dermal exposures are
unlikely to be significant. Dermal
exposure from bathing and showering
was estimated to contribute only 0.03%
of that from oral exposure (Xu et al.
2002). As with TCAA, due to the
limitations in dietary data and a clear
indication of exposure from other
E:\FR\FM\04JAR2.SGM
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ER04JA06.002</MATH>
RfD =
suggesting some presence in the
atmosphere (Reimann et al. 1996);
however, due to the low volatility (0.5—
0.7 mm Hg at 25 °C) of TCAA, exposure
from ambient air is expected to be
minimal. Dermal exposure to
disinfected water is also unlikely to be
significant. A study by Xu et al. (2002)
reports that dermal exposure from
bathing and showering is only 0.01% of
that from oral exposure. In addition, the
solvents trichloroethylene,
tetrachlorethylene, 1,1,1-trichloroethane
(often found in ambient air and drinking
water), and the disinfection byproduct
chloral hydrate all contribute to the
body’s TCAA load since each of these
compounds is metabolized to TCAA
(ATSDR 2004; ATSDR 1997a; ATSDR
1997b; USEPA 2000e). Due to the
limitations primarily in the dietary data
and a clear indication of exposure from
other sources, EPA applied a relative
source contribution of 20%.
MCAA. The MCLG for MCAA uses
the following calculations: An RfD of
0.01 mg/kg/day, a 70 kg adult
consuming 2 L/day of tap water, and a
relative source contribution of 20%.
The RfD included in the proposal was
based on a chronic drinking water study
in rats conducted by DeAngelo et al.
(1997). In the assessment presented for
the proposed rule, the LOAEL from this
study was identified as 3.5 mg/kg/day
based on increased absolute and relative
spleen weight in the absence of
histopathologic changes. After
reviewing comments and further
analysis of the data, EPA concludes that
it is more appropriate to identify this
ER04JA06.001</MATH>
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sources, EPA applied a relative source
contribution of 20%.
c. Summary of major comments. EPA
received few comments on MCAA and
TCAA. The majority of comments about
the MCLGs for TCAA and MCAA were
general MCLG questions, including RSC
derivation. Some commenters
questioned why MCAA, TCAA, and
chloroform were calculated using an
RSC of 20%. In particular, some
commenters compared these
calculations to that for DBCM in the
Stage 1 DBPR, which uses 80%. Each of
the MCLGs set for chloroform, TCAA,
and MCAA under this rule is calculated
using the best available science and EPA
Office of Water’s current approach for
deriving the RSC. EPA chose an RSC of
20%, not 80%, because of clear
indications of exposure from other
sources; data limitations preclude the
derivation of a specific RSC.
The RSC for DBCM was 80% in the
Stage 1 DBPR. The DBCM MCLG is not
part of today’s rulemaking. Any possible
future revision to the DBCM MCLG as
a result of an RSC change would not
affect the MCL for TTHM finalized in
today’s rule.
In response to comments received on
the RfD for MCAA, EPA has reviewed
the critical study regarding the
appropriateness of an increase in spleen
weight in the absence of histopathology
as a LOAEL. EPA has determined that
the dose associated with this endpoint
is more appropriately categorized as a
NOAEL rather than a LOAEL and has
revised the RfD and MCLG for MCAA.
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B. Consecutive Systems
Today’s rule includes provisions for
consecutive systems, which are public
water systems that receive some or all
of their finished water from another
water system (a wholesale system).
Consecutive systems face particular
challenges in providing water that meets
regulatory standards for DBPs and other
contaminants whose concentration can
increase in the distribution system.
Moreover, previous regulation of DBP
levels in consecutive systems varies
widely among States. In consideration
of these factors, EPA is finalizing
monitoring, compliance schedule, and
other requirements specifically for
consecutive systems. These
requirements are intended to facilitate
compliance by consecutive systems
with MCLs for TTHM and HAA5 under
the Stage 2 DBPR and help to ensure
that consumers in consecutive systems
receive equivalent public health
protection.
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1. Today’s Rule
As public water systems, consecutive
systems must provide water that meets
the MCLs for TTHM and HAA5 under
the Stage 2 DBPR, use specified
analytical methods, and carry out
associated monitoring, reporting,
recordkeeping, public notification, and
other requirements. The following
discusses a series of definitions needed
for addressing consecutive system
requirements in today’s rule. Later
sections of this preamble provide
further details on how rule requirements
(e.g., schedule and monitoring) apply to
consecutive systems.
A consecutive system is a public
water system that receives some or all
of its finished water from one or more
wholesale systems.
Finished water is water that has been
introduced into the distribution system
of a public water system and is intended
for distribution and consumption
without further treatment, except as
necessary to maintain water quality in
the distribution system (e.g., booster
disinfection, addition of corrosion
control chemicals).
A wholesale system is a public water
system that treats source water as
necessary to produce finished water and
then delivers finished water to another
public water system. Delivery may be
through a direct connection or through
the distribution system of one or more
consecutive systems.
The combined distribution system is
defined as the interconnected
distribution system consisting of the
distribution systems of wholesale
systems and of the consecutive systems
that receive finished water from those
wholesale system(s).
EPA is allowing States some
flexibility in defining what systems are
a part of a combined distribution
system. This provision determines
effective dates for requirements in
today’s rule; see Section IV.E
(Compliance Schedules) for further
discussion. EPA has consulted with
States and deferred to their expertise
regarding the nature of the connection
in making combined distribution system
determinations. In the absence of input
from the State, EPA will determine that
combined distribution systems include
all interconnected systems for the
purpose of determining compliance
schedules for implementation of this
rule.
2. Background and Analysis
The practice of public water systems
buying and selling water to each other
has been commonplace for many years.
Reasons include saving money on
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409
pumping, treatment, equipment, and
personnel; assuring an adequate supply
during peak demand periods; acquiring
emergency supplies; selling surplus
supplies; and delivering a better product
to consumers. EPA estimates that there
are more than 10,000 consecutive
systems nationally.
Consecutive systems face particular
challenges in providing water that meets
regulatory standards for contaminants
that can increase in the distribution
system. Examples of such contaminants
include coliforms, which can grow if
favorable conditions exist, and some
DBPs, including THMs and HAAs,
which can increase when a disinfectant
and DBP precursors continue to react in
the distribution system.
EPA included requirements
specifically for consecutive systems
because States have taken widely
varying approaches to regulating DBPs
in consecutive systems in previous
rules. For example, some States have
not regulated DBP levels in consecutive
systems that deliver disinfected water
but do not add a disinfectant. Other
States have determined compliance
with DBP standards based on the
combined distribution system that
includes both the wholesaler and
consecutive systems. In this case, sites
in consecutive systems are treated as
monitoring sites within the combined
distribution system. Neither of these
approaches provide the same level of
public health protection as nonconsecutive systems receive under the
Stage 1 DBPR. Once fully implemented,
today’s rule will ensure similar
protection for consumers in consecutive
systems.
In developing its recommendations,
the Stage 2 M-DBP Advisory Committee
recognized two principles related to
consecutive systems: (1) consumers in
consecutive systems should be just as
well protected as customers of all
systems, and (2) monitoring provisions
should be tailored to meet the first
principle. Accordingly, the Advisory
Committee recommended that all
wholesale and consecutive systems
comply with provisions of the Stage 2
DBPR on the same schedule required of
the wholesale or consecutive system
serving the largest population in the
combined distribution system. In
addition, the Advisory Committee
recommended that EPA solicit
comments on issues related to
consecutive systems that the Advisory
Committee had not fully explored
(USEPA 2000a). EPA agreed with these
recommendations and they are reflected
in today’s rule.
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3. Summary of Major Comments
Commenters generally supported the
proposed definitions. However,
commenters did express some concerns,
especially with including a time period
of water delivery that defined whether
a system was a consecutive system
(proposed to trigger plant-based
monitoring requirements) or wholesale
system (proposed to allow
determination that a combined
distribution system existed). EPA has
dropped this requirement from the final
rule; population-based monitoring
requirements in the final rule do not
need to define how long a plant must
operate in order to be considered a
plant, and EPA has provided some
flexibility for States to determine which
systems comprise a combined
distribution system (without presenting
a time criterion).
Other commenters expressed concern
that the proposed definition of
consecutive system was inconsistent
with use of the term prior to the
rulemaking. EPA acknowledges that the
Agency has not previously formally
defined the term, but believes that the
definition in today’s rule best considers
all commenters’ concerns, while also
providing for accountability and public
health protection in as simple a manner
as is possible given the many
consecutive system scenarios that
currently exist.
Several States requested flexibility to
determine which systems comprised a
combined distribution system under
this rule; EPA has included that
flexibility for situations in which
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systems have only a marginal
association (such as an infrequently
used emergency connection) with other
systems in the combined distribution
system. To prepare for the IDSE and
subsequent Stage 2 implementation,
EPA has worked with States in
identifying all systems that are part of
each combined distribution system.
Finally, several commenters requested
that the wholesale system definition
replace ‘‘public water system’’ with
‘‘water system’’ so that wholesale
systems serving fewer than 25 people
would not be considered public water
systems. EPA did not change the
definition in today’s rule; EPA considers
any water system to be a public water
system (PWS) if it serves 25 or more
people either directly (retail) or
indirectly (by providing finished water
to a consecutive system) or through a
combination of retail and consecutive
system customers. If a PWS receives
water from an unregulated entity, that
PWS must meet all compliance
requirements (including monitoring and
treatment techniques) that any other
public water system that uses source
water of unknown quality must meet.
C. LRAA MCLs for TTHM and HAA5
1. Today’s Rule
This rule requires the use of
locational running annual averages
(LRAAs) to determine compliance with
the Stage 2 MCLs of 0.080 mg/L TTHM
and 0.060 mg/L HAA5. All systems,
including consecutive systems, must
comply with the MCLs for TTHM and
HAA5 using sampling sites identified
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Fmt 4701
Sfmt 4700
under the Initial Distribution System
Evaluation (IDSE) or using existing
Stage 1 DBPR compliance monitoring
locations (as discussed in Section IV.F).
EPA has dropped the proposed phased
approach for LRAA implementation
(Stage 2A and Stage 2B) by removing
Stage 2A and redesignating Stage 2B as
Stage 2.
Details of monitoring requirements
and compliance schedules are discussed
in preamble Sections IV.G and IV.E,
respectively, and may be found in
subpart V of today’s rule.
2. Background and Analysis
The MCLs for TTHM and HAA5 are
the same as those proposed, 0.080 mg/
L TTHM and 0.060 mg/L HAA5 as an
LRAA. See the proposed rule (68 FR
49584, August 18, 2003) (USEPA 2003a)
for a more detailed discussion of the
analysis supporting the MCLs. The
primary objective of the LRAA is to
reduce exposure to high DBP levels. For
an LRAA, an annual average must be
computed at each monitoring location.
The RAA compliance basis of the 1979
TTHM rule and the Stage 1 DBPR allows
a system-wide annual average under
which high DBP concentrations in one
or more locations are averaged with, and
dampened by, lower concentrations
elsewhere in the distribution system.
Figure IV.C–1 illustrates the difference
in calculating compliance with the
MCLs for TTHM between a Stage 1
DBPR RAA, and the Stage 2 DBPR
LRAA.
BILLING CODE 6560–50–P
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BILLING CODE 6560–50–C
EPA and the Stage 2 M–DBP Advisory
Committee considered an array of
alternative MCL strategies. The
Advisory Committee discussions
primarily focused on the relative
magnitude of exposure reduction versus
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the expected impact on the water
industry and its customers. Strategies
considered included across the board
requirements, such as significantly
decreasing the MCLs (e.g., 40/30) or
single hit MCLs (e.g., all samples must
be below 80/60); and risk targeting
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411
requirements. In the process of
evaluating alternatives, EPA and the
Advisory Committee reviewed vast
quantities of data and many analyses
that addressed health effects, DBP
occurrence, predicted reductions in DBP
levels, predicted technology changes,
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and capital, annual, and household
costs. The Advisory Committee
recommended and EPA proposed the
risk targeting approach of 80/60 as an
LRAA preceded by an IDSE. Today’s
rule finalizes these requirements.
EPA has chosen compliance based on
an LRAA due to concerns about levels
of DBPs above the MCL in some
portions of the distribution system. The
LRAA standard will eliminate systemwide averaging of monitoring results
from different monitoring locations. The
individuals served in areas of the
distribution system with above average
DBP occurrence levels masked by
averaging under an RAA are not
receiving the same level of health
protection. Although an LRAA standard
still allows averaging at a single location
over an annual period, EPA concluded
that changing the basis of compliance
from an RAA to an LRAA will result in
decreased exposure to higher DBP levels
(see Section VI for predictions of DBP
reductions under the LRAA MCLs). This
conclusion is based on three
considerations:
(1) There is considerable evidence
that under the current RAA MCL
compliance monitoring requirements, a
small but significant proportion of
monitoring locations experience high
DBP levels at least some of the time. Of
systems that collected data under the
Information Collection Rule that met the
Stage 1 DBPR RAA MCLs, 14 percent
had TTHM single sample concentrations
greater than the Stage 1 MCL, and 21
percent had HAA5 single sample
concentrations above the MCL.
Although most TTHM and HAA5
samples were below 100 µg/L, some
ranged up to 140 µg/L and 130 µg/L,
respectively.
(2) In some situations, the populations
served by certain portions of the
distribution system consistently receive
water that exceeds 0.080 mg/L for
TTHM or 0.060 mg/L for HAA5 (both as
LRAAs) even though the system is in
compliance with Stage 1 MCLs). Of
Information Collection Rule systems
meeting the Stage 1 DBPR MCLs as
RAAs, five percent had monitoring
locations that exceeded 0.080 mg/L
TTHM and three percent exceeded
0.060 mg/L HAA5 as an annual average
(i.e., as LRAAs) by up to 25%
(calculated as indicated in Figure IV.C–
1). Customers served at these locations
consistently received water with TTHM
and/or HAA5 concentrations higher
than the system-wide average and
higher than the MCL.
(3) Compliance based on an LRAA
will remove the opportunity for systems
to average out samples from high and
low quality water sources. Some
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systems are able to comply with an RAA
MCL even if they have a plant with a
poor quality water source (that thus
produces high concentrations of DBPs)
because they have another plant that has
a better quality water source (and thus
lower concentrations of DBPs).
Individuals served by the plant with the
poor quality source will usually have
higher DBP exposure than individuals
served by the other plant.
In part, both the TTHM and HAA5
classes are regulated because they occur
at high levels and represent chlorination
byproducts that are produced from
source waters with a wide range of
water quality. The combination of
TTHM and HAA5 represent a wide
variety of compounds resulting from
bromine substitution and chlorine
substitution reactions (e.g., bromoform
has three bromines, TCAA has three
chlorines, BDCM has one bromine and
two chlorines). EPA believes that the
TTHM and HAA5 classes serve as an
indicator for unidentified and
unregulated DBPs. EPA believes that
controlling the occurrence levels of
TTHM and HAA5 will help control the
overall levels of chlorination DBPs.
3. Summary of Major Comments
Commenters supported the proposed,
risk-targeted MCL strategy over the
alternative MCL strategies that were
considered by the Advisory Committee
as the preferred regulatory strategy.
Commenters concurred with EPA’s
analysis that such an approach will
reduce peak and average DBP levels.
Commenters supported the Stage 2 longterm MCLs of 0.080 mg/L TTHM and
0.060 mg/L HAA5 as LRAAs.
EPA received many comments on
today’s MCLs specific to consecutive
systems. While commenters supported
consecutive system compliance with the
Stage 2 DBPR in order to provide
comparable levels of public health
protection, they noted that it would be
difficult for many consecutive systems
to meet Stage 2 requirements because
they have not had to meet the full scope
of DBP requirements under previous
rules. EPA has developed a training and
outreach program to assist these systems
and encourages States, wholesale
systems, and professional associations
to also provide assistance.
Some commenters expressed concern
about holding consecutive systems
responsible for water quality over which
they have no control. Several
commenters were concerned about the
establishment of contracts between
wholesale and consecutive systems,
including concern about a strain on
their relationship, wholesale system
reluctance to commit to keep DBPs at a
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level suggested by the consecutive
systems, and the time and money it
could take to work out differences.
Although setting up a contract is a
prudent business action, commenters
noted that small consecutive water
systems have few resources to sue for
damages should the wholesaler provide
water exceeding the MCL.
The purpose of DBPRs is to protect
public health from exposure to high
DBP levels. Not requiring violations
when distributed water exceeds MCLs
undermines the intent of the rule. While
EPA recognizes consecutive systems do
not have full control over the water they
receive, agreements between wholesale
and consecutive systems may specify
water quality and actions required of the
wholesaler if those water quality
standards are not met.
Finally, commenters recommended
that the Stage 2A provisions in the
proposed rule be removed. These
provisions (compliance with locational
running annual average MCLs of 0.120
mg/L for TTHM and 0.100 mg/L for
HAA5) required systems to comply with
the Stage 1 MCLs (as running annual
averages) and the Stage 2A MCLs (as
LRAAs) concurrently until systems were
required to comply with Stage 2B MCLs.
Commenters noted that having two
separate MCLs for an individual system
to comply with at the same time was
confusing to the system and its
customers. In addition, State resources
needed for compliance determinations
and data management for this short-term
requirement would be resourceintensive. Finally, resources spent to
comply with Stage 2A would be better
spent in complying with Stage 2B,
especially given that some of the
changes for Stage 2A compliance might
not provide any benefit for Stage 2B.
Since EPA agrees with commenters’
concerns, the Stage 2A requirements
have been removed from the final rule.
D. BAT for TTHM and HAA5
1. Today’s Rule
Today, EPA is identifying the best
available technology (BAT) for the
TTHM and HAA5 LRAA MCLs (0.080
mg/L and 0.060 mg/L respectively) for
systems that treat their own source
water as one of the three following
technologies:
(1) GAC10 (granular activated carbon
filter beds with an empty-bed contact
time of 10 minutes based on average
daily flow and a carbon reactivation
frequency of every 120 days)
(2) GAC20 (granular activated carbon
filter beds with an empty-bed contact
time of 20 minutes based on average
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daily flow and a carbon reactivation
frequency of every 240 days)
(3) Nanofiltration (NF) using a
membrane with a molecular weight
cutoff of 1000 Daltons or less.
EPA is specifying a different BAT for
consecutive systems than for systems
that treat their own source water to meet
the TTHM and HAA5 LRAA MCLs. The
consecutive system BAT is
chloramination with management of
hydraulic flow and storage to minimize
residence time in the distribution
system for systems that serve at least
10,000 people and management of
hydraulic flow and storage to minimize
residence time in the distribution
system for systems that serve fewer than
10,000 people.
2. Background and Analysis
The BATs are the same as was
proposed, except that consecutive
systems serving fewer than 10,000
people do not have chloramination as
part of the consecutive system BAT. See
the proposal (68 FR 49588, August 18,
2003) (USEPA 2003a) for more detail on
the analysis supporting these
requirements. The Safe Drinking Water
Act directs EPA to specify BAT for use
in achieving compliance with the MCL.
Systems unable to meet the MCL after
application of BAT can get a variance
(see Section IV.K for a discussion of
variances). Systems are not required to
use BAT in order to comply with the
MCL. PWSs may use any State-approved
technologies as long as they meet all
drinking water standards.
EPA examined BAT options first by
analyzing data from the Information
Collection Rule treatment studies
designed to evaluate the ability of GAC
and NF to remove DBP precursors.
Based on the treatment study results,
GAC is effective for controlling DBP
formation for waters with influent TOC
concentrations below approximately 6
mg/L (based on the Information
Collection Rule and NRWA data, over
90 percent of plants have average
influent TOC levels below 6 mg/L
(USEPA 2003c)). Of the plants that
conducted an Information Collection
Rule GAC treatment study,
approximately 70 percent of the surface
water plants studied could meet the
0.080 mg/L TTHM and 0.060 mg/L
HAA5 MCLs, with a 20 percent safety
factor (i.e., 0.064 mg/L and 0.048 mg/L,
respectively) using GAC with 10
minutes of empty bed contact time and
a 120 day reactivation frequency, and 78
percent of the plants could meet the
MCLs with a 20 percent safety factor
using GAC with 20 minutes of empty
bed contact time and a 240 day
reactivation frequency. Because the
treatment studies were conducted at
plants with much poorer water quality
than the national average, EPA believes
that much higher percentages of plants
nationwide could meet the MCLs with
the proposed GAC BATs.
Among plants using GAC, larger
systems would likely realize an
economic benefit from on-site
reactivation, which could allow them to
use smaller, 10-minute empty bed
contact time contactors with more
frequent reactivation (i.e., 120 days or
less). Most small systems would not
find it economically advantageous to
install on-site carbon reactivation
facilities, and thus would opt for larger,
20-minute empty bed contact time
contactors, with less frequent carbon
replacement (i.e., 240 days or less).
The Information Collection Rule
treatment study results also
demonstrated that nanofiltration was
the better DBP control technology for
ground water sources with high TOC
concentrations (i.e., above
approximately 6 mg/L). The results of
the membrane treatment studies showed
that all ground water plants could meet
the 0.080 mg/L TTHM and 0.060 mg/L
HAA5 MCLs, with a 20% safety factor
(i.e., 0.064 mg/L and 0.048 mg/L,
respectively) at the system average
distribution system residence time using
nanofiltration. Nanofiltration would be
less expensive than GAC for high TOC
ground waters, which generally require
minimal pretreatment prior to the
413
membrane process. Also, nanofiltration
is an accepted technology for treatment
of high TOC ground waters in Florida
and parts of the Southwest, areas of the
country with elevated TOC levels in
ground waters.
The second method that EPA used to
examine alternatives for BAT was the
Surface Water Analytical Tool model
that was developed to compare
alternative regulatory strategies as part
of the Stage 1 and Stage 2 M–DBP
Advisory Committee deliberations. EPA
modeled a number of BAT options. In
the model, GAC10 was defined as
granular activated carbon with an empty
bed contact time of 10 minutes and a
reactivation or replacement interval of
90 days or longer. GAC20 was defined
as granular activated carbon with an
empty bed contact time of 20 minutes
and a reactivation or replacement
interval of 90 days or longer.
The compliance percentages
forecasted by the SWAT model are
indicated in Table IV.D–1. EPA
estimates that more than 97 percent of
large systems will be able to achieve the
Stage 2 MCLs with the GAC BAT,
regardless of post-disinfection choice
(Seidel Memo, 2001). Because the
source water quality (e.g., DBP
precursor levels) in medium and small
systems is expected to be comparable to
or better than that for the large system
(USEPA 2005f), EPA believes it is
conservative to assume that at least 90
percent of medium and small systems
will be able to achieve the Stage 2 MCLs
if they were to apply one of the
proposed GAC BATs. EPA assumes that
small systems may adopt GAC20 in a
replacement mode (with replacement
every 240 days) over GAC10 because it
may not be economically feasible for
some small systems to install and
operate an on-site GAC reactivation
facility. Moreover, some small systems
may find nanofiltration cheaper than the
GAC20 in a replacement mode if their
specific geographic locations cause a
relatively high cost for routine GAC
shipment.
TABLE IV.D–1.—SWAT MODEL PREDICTIONS OF PERCENT OF LARGE PLANTS IN COMPLIANCE WITH TTHM AND HAA5
STAGE 2 MCLS AFTER APPLICATION OF SPECIFIED TREATMENT TECHNOLOGIES
Compliance with 0.080 mg/L TTHM and 0.060
mg/L HAA5 LRAAs
Compliance with 0.064 mg/L TTHM and 0.048
mg/L HAA5 LRAAs (MCLs with 20% Safety factor)
Residual disinfectant
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Technology
Chlorine (percent)
Enhanced Coagulation (EC) ....................
EC (no pre-disinfection) ...........................
EC & GAC10 ............................................
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73.5
73.4
100
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Chloramine
(percent)
76.9
88.0
97.1
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Residual
disinfectant
All systems
(percent)
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Chlorine (percent)
74.8
78.4
99.1
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44.1
100
04JAR2
Chloramine
(percent)
65.4
62.7
95.7
All systems
(percent)
60.4
50.5
98.6
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TABLE IV.D–1.—SWAT MODEL PREDICTIONS OF PERCENT OF LARGE PLANTS IN COMPLIANCE WITH TTHM AND HAA5
STAGE 2 MCLS AFTER APPLICATION OF SPECIFIED TREATMENT TECHNOLOGIES—Continued
Compliance with 0.080 mg/L TTHM and 0.060
mg/L HAA5 LRAAs
Compliance with 0.064 mg/L TTHM and 0.048
mg/L HAA5 LRAAs (MCLs with 20% Safety factor)
Residual disinfectant
Technology
Chlorine (percent)
EC & GAC20 ............................................
EC & All Chloramines ..............................
100
NA
Chloramine
(percent)
Residual
disinfectant
All systems
(percent)
100
83.9
Chlorine (percent)
100
NA
Chloramine
(percent)
100
NA
100
73.6
All systems
(percent)
100
NA
Note: Enhanced coagulation/softening is required under the Stage 1 DBPR for conventional plants.
Source: Seidel (2001).
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The BAT requirements for large
consecutive systems are the same as
proposed, but the requirements have
changed for small consecutive systems.
EPA believes that the best compliance
strategy for consecutive systems is to
collaborate with wholesalers on the
water quality they need. For consecutive
systems that are having difficulty
meeting the MCLs, EPA is specifying a
BAT of chloramination with
management of hydraulic flow and
storage to minimize residence time in
the distribution system for systems
serving at least 10,000 and management
of hydraulic flow and storage to
minimize residence time in the
distribution system for systems serving
fewer than 10,000. EPA believes that
small consecutive systems can use this
BAT to comply with the Stage 2 DBPR,
but if they cannot, then they can apply
to the State for a variance.
Chloramination has been used for
residual disinfection for many years to
minimize the formation of chlorination
DBPs, including TTHM and HAA5
(USEPA 2003d). EPA estimates that over
50 percent of large subpart H systems
serving at least 10,000 use
chloramination for Stage 1. The BAT
provision to manage hydraulic flow and
minimize residence time in the
distribution system is to facilitate the
maintenance of the chloramine residual
and minimize the likelihood for
nitrification. EPA has not included
chloramination for consecutive systems
as part of the BAT for systems serving
fewer than 10,000 due to concerns about
their ability to properly control the
process, given that many have no
treatment capability or expertise and the
Agency’s concern about such systems
having operational difficulties such as
distribution system nitrification.
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EPA believes that the BATs for
nonconsecutive systems are not
appropriate for consecutive systems
because their efficacy in controlling
DBPs is based on precursor removal.
Consecutive systems face the unique
challenge of receiving waters in which
DBPs are already present if the
wholesale system has used a residual
disinfectant, which the BATs for nonconsecutive systems do not effectively
remove. GAC is not cost-effective for
removing DBPs. Nanofiltration is only
moderately effective at removing THMs
or HAAs if membranes with a very low
molecular weight cutoff (and very high
cost of operation are employed).
Therefore, GAC and nanofiltration are
not appropriate BATs for consecutive
systems.
3. Summary of Major Comments
Commenters concurred with EPA’s
identification of BATs for nonconsecutive systems but expressed
concern about the BAT for consecutive
systems. Many commenters agreed that
Stage 2 compliance for consecutive
systems would usually best be achieved
by improved treatment by the wholesale
system. However, they noted that the
proposed BAT may not be practical for
compliance if water delivered to the
consecutive system is at or near DBP
MCLs. In addition, chloramination
requires operator supervision and
adjustment and many consecutive
systems that buy water may be reluctant
to operate chemical feed systems.
Therefore, EPA included chloramines as
part of the BAT in today’s rule only for
systems serving at least 10,000 because
of the operator attention it requires and
concerns with safety and nitrification.
While some commenters believed that
having a BAT for consecutive systems
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contradicts the premise of the Stage 1
DBPR that DBPs are best controlled
through TOC removal and optimizing
disinfection processes, the SDWA
requires EPA to identify a BAT for all
systems required to meet an MCL. No
commenter recommended an alternative
BAT. EPA still believes that precursor
removal remains a highly effective
strategy to reduce DBPs. Thus, EPA
encourages States to work with
wholesale systems and consecutive
systems to identify strategies to ensure
compliance, especially those systems
with DBP levels close to the MCL.
E. Compliance Schedules
1. Today’s Rule
This section specifies compliance
dates for the IDSE and MCL compliance
requirements in today’s rule. As
described elsewhere in Section IV of
this preamble, today’s rule requires
PWSs to carry out the following
activities:
• Conduct initial distribution system
evaluations (IDSEs) on a required
schedule. Systems may comply by using
any of four approaches for which they
qualify (standard monitoring, system
specific study, 40/30 certification, or
very small system waiver).
• Determine Stage 2 monitoring
locations based on the IDSE.
• Comply with Stage 2 MCLs on a
required schedule.
Compliance dates for these activities
vary by PWS size. Table IV.E–1 and
Figure IV.E–1 specify IDSE and Stage 2
compliance dates. Consecutive systems
of any size must comply with the
requirements of the Stage 2 DBPR on the
same schedule as required for the largest
system in the combined distribution
system.
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415
TABLE IV.E–1.—IDSE AND STAGE 2 COMPLIANCE DATES
Compliance dates by PWS size (retail population served) 1
Requirement
CWSs and
NTNCWSs serving
at least 100,000
CWSs and
NTNCWSs serving
50,000–99,999
CWSs and
NTNCWSs serving
10,000–49,999
CWSs serving
<10,000
Submit IDSE monitoring plan OR
Submit IDSE system specific
study plan OR.
Submit 40/30 certification OR .....
Receive very small system waiver from State.
Complete standard monitoring or
system specific study.
Submit IDSE Report ...................
Begin subpart V (Stage 2) compliance monitoring 2.
October 1, 2006 .....
April 1, 2007 ...........
October 1, 2007 .....
April 1, 2008 .......
Not applicable.
September 30, 2008
March 31, 2009 ......
September 30, 2009
March 31, 2010 ..
Not applicable.
January 1, 2009 .....
April 1, 2012 ...........
July 1, 2009 ............
October 1, 2012 .....
January 1, 2010 .....
October 1, 2013 .....
July 1, 2010 .......
October 1, 2013
(October 1,
2014 if Cryptosporidium monitoring is required under
Subpart W)..
Not applicable.
NTNCWSs serving
<10,000
1 Wholesale and consecutive systems that are part of a combined distribution system must comply based on the schedule required of the largest system in the combined distribution system.
2 States may grant up to an additional 2 years for systems making capital improvements.
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2. Background and Analysis
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The compliance schedule in today’s
final rule stems from the risk-targeted
approach of the rule, wherein PWSs
conduct initial monitoring to determine
locations and concentrations of high
DBPs. A primary objective of this
schedule is to ensure that PWSs identify
locations with high DBP concentrations
and provide appropriate additional
treatment in a timely manner for high
risk areas, while not requiring low risk
systems to add additional treatment.
The compliance schedule balances the
objective of early risk-targeted
monitoring with adequate time for
PWSs and the State or primacy agency
to assure full implementation and
compliance. EPA is establishing
concurrent compliance schedules under
the Stage 2 DBPR for all systems (both
wholesale systems and consecutive
systems) in a particular combined
distribution system because this will
assure comparable risk-based targeting
information being available at the same
time for all PWSs that are part of a
combined distribution system and
thereby allow for more cost-effective
compliance with TTHM and HAA5
MCLs.
SDWA section 1412(b)(10) states that
a drinking water regulation shall take
effect 3 years from the promulgation
date unless the Administrator
determines that an earlier date is
practicable. Today’s rule requires PWSs
to begin monitoring prior to 3 years
from the promulgation date. Based on
EPA’s assessment and recommendations
of the Advisory Committee, as described
in this section, EPA has determined that
these monitoring start dates are
practicable and appropriate.
Systems must submit their IDSE plans
(monitoring plans for standard
monitoring, study plans for system
specific studies) to the primacy agency
for review and approval. The State or
primacy agency will then have 12
months to review, and, as necessary,
consult with the system. A number of
PWSs will then conduct one year of
distribution system monitoring for
TTHM and HAA5 at locations other
than those currently used for Stage 1
DBPR compliance monitoring. At the
conclusion of this monitoring, these
PWSs have three months to evaluate
analysis and monitoring results and
submit Stage 2 compliance monitoring
locations and schedules to the State or
primacy agency. Where required, PWSs
must provide the necessary level of
treatment to comply with the Stage 2
MCLs within three years of the
completion of State or primacy agency
review of the IDSE report, though States
may allow an additional two years for
PWSs making capital improvements.
EPA has modified the proposed
compliance schedule to stagger
monitoring start dates for PWSs serving
10,000 to 99,999 people and to allow
more time for development and review
of IDSE monitoring plans prior to the
start of monitoring. The following
discussion addresses these changes from
the proposal.
The proposed rule required all PWSs
serving at least 10,000 people (plus
smaller systems that are part of a
combined distribution system with a
PWS that serves at least 10,000 people)
to complete IDSE monitoring and
submit IDSE reports (including
recommended Stage 2 compliance
monitoring locations) two years after
rule promulgation, followed by one year
for review of IDSE reports, after which
systems had three years to come into
compliance with Stage 2B MCLs.
Under today’s final rule, PWSs
serving at least 100,000 people (plus
smaller systems that are part of the
combined distribution system) will meet
the same Stage 2 compliance deadlines
as proposed. However, the timing of the
IDSE has been changed to allow for a
more even workload and a greater
opportunity for primacy agency
involvement (e.g., through monitoring
plan review and approval). The IDSE
plan submission dates for PWSs serving
50,000 to 99,999 people (plus smaller
systems that are part of the combined
distribution system) will be 12 months
after the effective date; for PWSs serving
10,000 to 49,999 (plus smaller systems
that are part of the combined
distribution system), the IDSE plan
submission dates will be 18 months
after the effective date. The Stage 2
compliance schedule for systems
serving fewer than 10,000 people
remains the same as proposed. Stage 2
MCL compliance dates are modified
accordingly.
This staggering of IDSE start dates for
PWSs serving 10,000 to 99,999 people is
advantageous in several respects:
• Provides PWSs greater assurance
that IDSEs are properly conducted by
requiring IDSE plan review prior to
conducting the IDSE.
• Provides additional time to develop
budgets and establish contracts with
laboratories.
• Spreads out the workload for
technical assistance and guidance. The
staggered schedule will allow States and
EPA to provide more support to
individual PWSs as needed.
• Provides time for DBP analytical
laboratories to build capacity as needed
to accommodate the sample analysis
needs of PWSs and extends and
smooths the demand for laboratory
services.
• Maintains simultaneous rule
compliance with the LT2ESWTR as
recommended by the Stage 2 M-DBP
Advisory Committee and as mandated
by the 1996 SDWA Amendments, which
require that EPA ‘‘minimize the overall
risk of adverse health effects by
balancing the risk from the contaminant
and the risk from other contaminants
the concentrations of which may be
affected by the use of a treatment
technique or process that would be
employed to attain the maximum
contaminant level’’ (Sec.
1412(b)(5)(B)(i)).
The Advisory Committee
recommended the Initial Distribution
System Evaluation, as discussed in
Section IV.F, and EPA is finalizing an
IDSE schedule generally consistent with
the Advisory Committee timeframe
recommendation, but modified to
stagger the schedule for systems serving
more than 10,000 but less than 100,000,
and to address public comments on the
IDSE requirements.
For all systems, the IDSE schedule has
been revised to allow systems to submit
and States or primacy agencies to
review (and revise, if necessary)
systems’ recommendations for IDSE and
Stage 2 monitoring locations, while still
allowing systems three years after
completion of the State or primacy
agency review of Stage 2 compliance
monitoring locations to make necessary
treatment and operational changes to
comply with Stage 2 MCLs.
Figure IV.E–2 illustrates compliance
schedules for examples of three
combined distribution systems, with the
schedule dictated by the retail
population served by the largest system.
FIGURE IV.E–2.—SCHEDULE EXAMPLES.
—Wholesale system (pop. 64,000) with three consecutive systems (pops. 21,000; 15,000; 5,000):
—IDSE monitoring plan due for all systems April 1, 2007 since wholesale system serves 50,000–99,999
—Stage 2 compliance beginning October 1, 2012 for all systems
—Wholesale system (pop. 4,000) with three consecutive systems (pops. 21,000; 5,000; 5,000):
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FIGURE IV.E–2.—SCHEDULE EXAMPLES.—Continued
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—IDSE monitoring plan due for all systems October 1, 2007 since the largest system in combined distribution system serves 10,000–
49,999
—Stage 2 compliance beginning October 1, 2013 for all systems
—Wholesale system (pop. 4,000) with three consecutive systems (pops. 8,000; 5,000; 5,000):
—IDSE monitoring plan due for all systems April 1, 2008 since no individual system in combined distribution system exceeds 10,000 (even
though total population exceeds 10,000)
—Stage 2 compliance beginning October 1, 2013 if no Cryptosporidium monitoring under the LT2ESWTR is required or beginning October
1, 2014 if Cryptosporidium monitoring under the LT2ESWTR is required
This schedule requires wholesale
systems and consecutive systems that
are part of a combined distribution
system with at least one system with an
earlier compliance deadline to conduct
their IDSE simultaneously so that the
wholesale system will be aware of
compliance challenges facing the
consecutive systems and will be able to
implement treatment plant, capital, and
operational improvements as necessary
to ensure compliance of both the
wholesale and consecutive systems. The
Advisory Committee and EPA both
recognized that DBPs, once formed, are
difficult to remove and are generally
best addressed by treatment plant
improvements, typically through
precursor removal or use of alternative
disinfectants. For a wholesale system to
make the best decisions concerning the
treatment steps necessary to meet
TTHM and HAA5 LRAAs under the
Stage 2 DBPR, both in its own
distribution system and in the
distribution systems of consecutive
systems it serves, the wholesale system
must know the DBP levels throughout
the combined distribution system.
Without this information, the wholesale
system may design treatment changes
that allow the wholesale system to
achieve compliance, but leave the
consecutive system out of compliance.
In summary, the compliance schedule
for today’s rule maintains the earliest
compliance dates recommended by the
Advisory Committee for PWSs serving
at least 100,000 people (plus smaller
systems that are part of the combined
distribution system). These PWSs serve
the majority of people. The schedule
also maintains the latest compliance
dates the Advisory Committee
recommended, which apply to PWSs
serving fewer than 10,000 people. EPA
has staggered compliance schedules for
PWSs between these two size categories
in order to facilitate implementation of
the rule. This staggered schedule is
consistent with the schedule required
under the LT2ESWTR promulgated
elsewhere in today’s Federal Register.
3. Summary of Major Comments
EPA received significant public
comment on the compliance schedule in
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the August 18, 2003 proposal. Major
issues raised by commenters include
providing more time for PWSs to
prepare for monitoring, giving States or
primacy agencies more time to oversee
monitoring, and establishing consistent
schedules for consecutive PWSs. A
summary of these comments and EPA’s
responses follows.
Standard monitoring plan and system
specific study plan preparation. Many
commenters were concerned about the
proposed requirement to develop and
execute an IDSE monitoring plan
without any primacy agency review.
PWSs specifically expressed concern
about the financial commitment without
prior State approval and noted that
some PWSs would need more than the
time allowed under the proposed rule to
develop and implement an IDSE
monitoring plan, especially without an
opportunity for State or primacy agency
review and approval. Smaller PWSs
may require substantial time and
planning to budget for IDSE expenses,
especially for systems that have not
previously complied with DBP MCLs.
EPA recognizes these concerns and
today’s final rule provides time for
PWSs to submit IDSE plans (monitoring
plans, study plans, or 40/30
certifications) for State or primacy
agency review and more time before
having to begin monitoring.
Specifically, PWSs serving 50,000 to
99,999 people and those serving 10,000
to 49,999 people must submit IDSE
plans about 12 months and 18 months
after the effective date, respectively, and
complete standard monitoring or a
system specific study within two years
after submitting their IDSE plan. This is
significantly more time than was
specified under the proposal, where
these systems would have had to
conduct their IDSE and submit their
IDSE report 24 months after the effective
date. PWSs serving at least 100,000
people must submit IDSE plans about
six months after the effective date and
complete standard monitoring or a
system specific study about 30 months
after the effective date, which also
provides more time than was specified
under the proposal. PWSs serving fewer
than 10,000 people, not associated with
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a larger system in their combined
distribution system, do not begin
monitoring until more than 36 months
after the effective date.
EPA believes that the final
compliance schedule allows PWSs
sufficient time to develop IDSE plans
with these compliance dates. The
schedule also allows 12 months for
State or primacy agency review of IDSE
plans, which allows additional time for
review and for coordination with
systems and provides more time to
address deficiencies in IDSE plans. This
is especially important for smaller
PWSs, which are likely to need the most
assistance from States. By staggering
monitoring start dates, today’s rule also
eases implementation by reducing the
number of PWSs that will submit plans
at any one time, when the most
assistance from regulatory agencies will
be required.
In summary, today’s schedule has
been modified so that systems are
required to submit IDSE plans for
primacy agency review and approval
prior to conducting their IDSE. Systems
can consider that their plan has been
approved if they have not heard back
from the State by the end of the State
review period. Systems are also required
to conduct the approved monitoring and
submit their IDSE report (including the
system’s recommended Stage 2
compliance monitoring) for State or
primacy agency review on a schedule
that allows for systems to still have a
minimum of full three years to comply
with Stage 2 following State or primacy
agency review of the system’s Stage 2
recommended monitoring. As with the
review of plans, systems can consider
that their IDSE report has been
approved if they have not heard back
from the State by the end of the State
review period.
State/primacy agency oversight. EPA
is preparing to support implementation
of IDSE requirements that must be
completed prior to States achieving
primacy. Several States have expressed
concern about EPA providing guidance
and reviewing reports from systems that
the State has permitted, inspected, and
worked with for a long time. These
States believe that their familiarity with
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the systems enables them to make the
best decisions to implement the rule
and protect public health and that the
rule requirement should be delayed
until States receive primacy.
Commenters were concerned that some
States will not participate in early
implementation activities and indicated
that States would prefer monitoring to
begin 24 months after rule
promulgation. Commenters also noted
that States need sufficient time to
become familiar with the rule, train
their staff, prepare primacy packages,
and train PWSs.
EPA agrees that State familiarity is an
important component of the review and
approval process, looks forward to
working closely with the State drinking
water program representatives during
IDSE implementation, and welcomes
proactive State involvement. However,
the Agency believes that delaying
implementation of risk-based IDSE
targeting activities until States receive
primacy is an unacceptable delay in
public health protection and also
inconsistent with the Advisory
Committee’s recommendations. EPA
remains committed to working with
States to the greatest extent feasible to
implement today’s rule, consistent with
the schedule promulgated today. For
States unable to actively participate in
IDSE implementation, however, EPA
believes it has an obligation to provide
support and guidance to PWSs who are
covered and independently responsible
for complying with the IDSE
requirements of today’s rule and is
prepared to oversee implementation.
Moreover, EPA believes that the
staggered compliance schedule in
today’s final rule will enhance States’
ability to help implement the rule.
Consecutive systems. Most
commenters supported consecutive
systems being on the same IDSE
schedule as wholesale systems,
recognizing the benefits of treatment
plant capital and operational
improvements by the wholesale system
as the preferred method of DBP
compliance, with the timely collection
of DBP data throughout the combined
distribution system a key component.
Several commenters preferred that
consecutive systems have a later Stage
2 compliance date to allow for
evaluation of whether wholesale system
treatment changes are adequate to
ensure compliance and to consider
changes to water delivery specifications.
EPA disagrees with those commenters
recommending a different Stage 2
compliance date and thus has
maintained the approach in the
proposal, which keeps all systems that
are part of a combined distribution
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system (the interconnected distribution
system consisting of the distribution
systems of wholesale systems and of the
consecutive systems that receive
finished water) on the same Stage 2
compliance schedule. Extending the
Stage 2 compliance dates would
unnecessarily delay the public health
protection afforded by this rule.
Consecutive systems must be able to
evaluate whether wholesale system
changes are sufficient to ensure
compliance and, if they are not, to make
cost-effective changes to ensure
compliance where wholesale system
efforts address some, but not all, of the
concerns with compliance. Public
health protection through compliance
with Stage 2 MCLs will occur on the
schedule of the largest system for all
systems in the combined distribution
system (regardless of size). If a
consecutive system must make capital
improvements to comply with this rule,
the State may use its existing authority
to grant up to an additional 24 months
to that system. In addition,
implementation and data tracking will
be simplified because all systems in a
combined distribution system will be on
the same IDSE and Stage 2 compliance
schedule. EPA believes that this is a
better approach from both a public
health standpoint and an
implementation standpoint.
EPA agrees with many commenters
that a high level of coordination among
wholesaler, consecutive system, and
States will be necessary to ensure
compliance. The schedule in today’s
rule provides more time for planning,
reviewing, and conducting the IDSE
than the schedule in the proposed rule,
which will allow more time for
necessary coordination, including small
consecutive systems that need help in
negotiations with their wholesale
system. EPA will work with ASDWA
and States to develop guidance to
facilitate wholesale/consecutive system
cooperation. This additional time and
the staggered schedule discussed in this
section also lessens the laboratory
burden associated with IDSE
monitoring.
The staggered schedule also helps
address commenter concerns about
evaluating combined distribution
systems. Other commenters’ concerns
about time needed for developing
contracts between systems and for
planning, funding, and implementing
treatment changes are addressed by not
requiring Stage 2 compliance until at
least six years following rule
promulgation.
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419
F. Initial Distribution System Evaluation
(IDSE)
1. Today’s Rule
Today’s rule establishes requirements
for systems to perform an Initial
Distribution System Evaluation (IDSE).
The IDSE is intended to identify sample
locations for Stage 2 compliance
monitoring that represent distribution
system sites with high DBP
concentrations. Systems will develop an
IDSE plan, collect data on DBP levels
throughout their distribution system,
evaluate these data to determine which
sampling locations are most
representative of high DBP levels, and
compile this information into a report
for submission to the State or primacy
agency. Systems must complete one
IDSE to meet the requirements of
today’s rule.
a. Applicability. This requirement
applies to all community water systems,
and to large nontransient
noncommunity water systems (those
serving at least 10,000 people) that use
a primary or residual disinfectant other
than ultraviolet light, or that deliver
water that has been treated with a
primary or residual disinfectant other
than ultraviolet light. Systems serving
fewer than 500 people are covered by
the very small system waiver provisions
of today’s rule and are not required to
complete an IDSE if they have TTHM
and HAA5 data collected under Subpart
L. Consecutive systems are subject to
the IDSE requirements of today’s rule.
Consecutive systems must comply with
IDSE requirements on the same
schedule as the system serving the
largest population in the combined
distribution system, as described in
section IV.E.
b. Data collection. For those systems
not receiving a very small system
waiver, there are three possible
approaches by which a system can meet
the IDSE requirement.
i. Standard monitoring. Standard
monitoring requires one year of DBP
monitoring throughout the distribution
system on a specified schedule. Prior to
commencing standard monitoring,
systems must prepare a monitoring plan
and submit it to the primacy agency for
review. The frequency and number of
samples required under standard
monitoring is determined by source
water type and system size. The number
of samples does not depend on the
number of plants per system. Section
IV.G provides a detailed discussion of
the specific population-based
monitoring requirements for IDSE
standard monitoring. Although standard
monitoring results are not to be used for
determining compliance with MCLs,
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systems are required to include
individual sample results for the IDSE
results when determining the range of
TTHM and HAA5 levels to be reported
in their Consumer Confidence Report
(see section IV.J).
ii. System specific study. Under this
approach, systems may choose to
perform a system specific study based
on earlier monitoring studies or
distribution system hydraulic models in
lieu of standard monitoring. Prior to
commencing a system specific study,
systems must prepare a study plan and
submit it to the primacy agency for
approval. The two options for system
specific studies are: (1) TTHM and
HAA5 monitoring data that encompass
a wide range of sample sites
representative of the entire distribution
system, including those judged to
represent high TTHM and HAA5
concentrations, and (2) extended period
simulation hydraulic models that
simulate water age in the distribution
system, in conjunction with one round
of TTHM and HAA5 sampling.
iii. 40/30 certification. Under this
approach, systems must certify to their
State or primacy agency that every
individual compliance sample taken
under subpart L during the period
specified in Table IV.F–2 were less than
or equal to 0.040 mg/L for TTHM and
less than or equal to 0.030 mg/L for
HAA5, and that there were no TTHM or
HAA5 monitoring violations during the
same period. The State or primacy
agency may require systems to submit
compliance monitoring results,
distribution system schematics, or
recommend subpart V compliance
monitoring locations as part of the
certification. This certification must be
kept on file and submitted to the State
or primacy agency for review. Systems
that qualify for reduced monitoring for
the Stage 1 DBPR during the two years
prior to the start of the IDSE may use
results of reduced Stage 1 DBPR
monitoring to prepare the 40/30
certification. The requirements for the
40/30 certification are listed in Table
IV.F–1.
TABLE IV.F–1.—40/30 CERTIFICATION REQUIREMENTS
40/30 Certification Requirements ...
• A certification that every individual compliance sample taken under subpart L during the period specified
in Table IV.F–2 were less than or equal to 0.040 mg/L for TTHM and less than or equal to 0.030 mg/L
for HAA5, and that there were no TTHM or HAA5 monitoring violations during the same period.
• Compliance monitoring results, distribution system schematics, and/or recommended subpart V compliance monitoring locations as required by the State or primacy agency.
TABLE IV.F–2.—40/30 ELIGIBILITY DATES
Then your eligibility for 40/30 certification is based on eight consecutive
calendar quarters of subpart L compliance monitoring results beginning
no earlier than1
If your 40/30 Certification Is Due
(1)
(2)
(3)
(4)
October 1, 2006 ..................................................................................
April 1, 2007 ........................................................................................
October 1, 2007 ..................................................................................
April 1, 2008 ........................................................................................
January
January
January
January
2004.
2004.
2005.
2005.
1 Unless you are on reduced monitoring under subpart L and were not required to monitor during the specified period. If you did not monitor
during the specified period, you must base your eligibility on compliance samples taken during the 12 months preceding the specified period.
c. Implementation. All systems
subject to the IDSE requirement under
this final rule (except those covered by
the very small system waiver) must
prepare and submit an IDSE plan
(monitoring plan for standard
monitoring, study plan for system
specific study) or 40/30 certification to
the State or primacy agency. IDSE plans
and 40/30 certifications must be
submitted according to the schedule
described in section IV.E and IV.M. The
requirements for the IDSE plan depend
on the IDSE approach that the system
selects and are listed in Tables IV.F–1
and IV.F–3.
TABLE IV.F–3.—IDSE MONITORING PLAN REQUIREMENTS
IDSE data collection alternative
IDSE plan requirements
Standard Monitoring ........................
• Schematic of the distribution system (including distribution system entry points and their sources, and
storage facilities), with notes indicating locations and dates of all projected standard monitoring, and all
projected subpart L compliance monitoring.
• Justification for all standard monitoring locations selected and a summary of data relied on to select
those locations.
• Population served and system type (subpart H or ground water).
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System Specific Study:
Hydraulic Model ..............................
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Hydraulic models must meet the following criteria:
• Extended period simulation hydraulic model.
• Simulate 24 hour variation in demand and show a consistently repeating 24 hour pattern of residence
time.
• Represent 75% of pipe volume; 50% of pipe length; all pressure zones; all 12-inch diameter and larger
pipes; all 8-inch and larger pipes that connect pressure zones, influence zones from different sources,
storage facilities, major demand areas, pumps, and control valves, or are known or expected to be significant conveyors of water; all pipes 6 inches and larger that connect remote areas of a distribution system to the main portion of the system; all storage facilities with standard operations represented in the
model; all active pump stations with controls represented in the model; and all active control valves.
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TABLE IV.F–3.—IDSE MONITORING PLAN REQUIREMENTS—Continued
IDSE data collection alternative
IDSE plan requirements
• The model must be calibrated, or have calibration plans, for the current configuration of the distribution
system during the period of high TTHM formation potential. All storage facilities must be evaluated as
part of the calibration process.
• All required calibration must be completed no later than 12 months after plan submission.
Submission must include:
• Tabular or spreadsheet data demonstrating percent of total pipe volume and pipe length represented in
the model, broken out by pipe diameter, and all required model elements.
• A description of all calibration activities undertaken, and if calibration is complete, a graph of predicted
tank levels versus measured tank levels for the storage facility with the highest residence time in each
pressure zone, and a time series graph of the residence time at the longest residence time storage facility in the distribution system showing the predictions for the entire simulation period (i.e., from time zero
until the time it takes for the model to reach a consistently repeating pattern of residence time).
• Model output showing preliminary 24 hour average residence time predictions throughout the distribution
system.
• Timing and number of samples planned for at least one round of TTHM and HAA5 monitoring at a number of locations no less than would be required for the system under standard monitoring in § 141.601
during the historical month of high TTHM. These samples must be taken at locations other than existing
subpart L compliance monitoring locations.
• Description of how all requirements will be completed no later than 12 months after submission of the
system specific study plan.
• Schematic of the distribution system (including distribution system entry points and their sources, and
storage facilities), with notes indicating the locations and dates of all completed system specific study
monitoring (if calibration is complete) and all subpart L compliance monitoring.
• Population served and system type (subpart H or ground water).
• If the model submitted does not fully meet the requirements, the system must correct the deficiencies
and respond to State inquiries on a schedule the State approves, or conduct standard monitoring.
System Specific Study:
Existing Monitoring Results ............
Existing monitoring results must meet the following criteria:
• TTHM and HAA5 results must be based on samples collected and analyzed in accordance with
§ 141.131. Samples must be collected within five years of the study plan submission date.
• The sampling locations and frequency must meet the requirements identified in Table IV.F–4. Each location must be sampled once during the peak historical month for TTHM levels or HAA5 levels or the
month of warmest water temperature for every 12 months of data submitted for that location. Monitoring
results must include all subpart L compliance monitoring results plus additional monitoring results as
necessary to meet minimum sample requirements.
Submission must include:
• Previously collected monitoring results
• Certification that the reported monitoring results include all compliance and non-compliance results generated during the time period beginning with the first reported result and ending with the most recent
subpart L results.
• Certification that the samples were representative of the entire distribution system and that treatment
and distribution system have not changed significantly since the samples were collected.
• Schematic of the distribution system (including distribution system entry points and their sources, and
storage facilities), with notes indicating the locations and dates of all completed or planned system specific study monitoring.
• Population served and system type (subpart H or ground water).
• If a system submits previously collected data that fully meet the number of samples required for IDSE
monitoring in Table IV.F–4 and some of the data are rejected due to not meeting the additional requirements, the system must either conduct additional monitoring to replace rejected data on a schedule the
State approves, or conduct standard monitoring.
TABLE IV.F–4.—SSS EXISTING MONITORING DATA SAMPLE REQUIREMENTS.
System type
Population size category
Number of
monitoring locations
Number of samples
TTHM
HAA5
Subpart H:
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9
6
36
36
12
72
72
24
144
144
250,000–999,999
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50,000–249,999
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10,000–49,999
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3,301–9,999
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<500
36
216
216
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TABLE IV.F–4.—SSS EXISTING MONITORING DATA SAMPLE REQUIREMENTS.—Continued
System type
Population size category
Number of
monitoring locations
Number of samples
TTHM
HAA5
1,000,000–4,999,999
48
288
288
≥ 5,000,000
60
360
360
<500
3
3
3
500–9,999
3
9
9
10,000–99,999
12
48
48
100,000–499,999
18
72
72
≥ 500,000
24
96
96
Ground Water:
The State or primacy agency will
approve the IDSE plan or 40/30
certification, or request modifications. If
the State or primacy agency has not
taken action by the date specified in
section IV.E or has not notified the
system that review is not yet complete,
systems may consider their submissions
to be approved. Systems must
implement the IDSE option described in
the IDSE plan approved by the State or
primacy agency according to the
schedule described in section IV.E.
All systems completing standard
monitoring or a system specific study
must submit a report to the State or
primacy agency according to the
schedule described in section IV.E.
Systems that have completed their
system specific study at the time of
monitoring plan submission may submit
a combined monitoring plan and report
on the required schedule for IDSE plan
submissions. The requirements for the
IDSE report are listed in Table IV.F–5.
Some of these reporting requirements
have changed from the proposal to
reduce reporting and paperwork burden
on systems.
TABLE IV.F–5.—IDSE REPORT REQUIREMENTS
IDSE data collection alternative
IDSE report requirements
Standard Monitoring ........................
• All subpart L compliance monitoring and standard monitoring TTHM and HAA5 analytical results in a
tabular format acceptable to the State.
• If changed from the monitoring plan, a schematic of the distribution system, population served, and system type.
• An explanation of any deviations from the approved monitoring plan.
• Recommendations and justifications for subpart V compliance monitoring locations and timing.
• All subpart L compliance monitoring and all system specific study monitoring TTHM and HAA5 analytical
results conducted during the period of the system specific study in a tabular or spreadsheet form acceptable to the State.
• If changed from the study plan, a schematic of the distribution system, population served, and system
type.
• If using the modeling provision, include final information for required plan submissions and a 24-hour
time series graph of residence time for each subpart V compliance monitoring location selected.
• An explanation of any deviations from the original study plan.
• All analytical and modeling results used to select subpart V compliance monitoring locations that show
that the system specific study characterized TTHM and HAA5 levels throughout the entire distribution
system.
• Recommendations and justifications for subpart V compliance monitoring locations and timing.
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System Specific Study ....................
All systems must prepare Stage 2
compliance monitoring
recommendations. All IDSE reports
must include recommendations for
Stage 2 compliance monitoring
locations and sampling schedule.
Systems submitting a 40/30 certification
must include their Stage 2 compliance
monitoring recommendations in their
Stage 2 (Subpart V) monitoring plan
unless the State requests Subpart V site
recommendations as part of the 40/30
certification. The number of sampling
locations and the criteria for their
selection are described in § 141.605 of
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today’s final rule, and in section IV.G.
Generally, a system must recommend
locations with the highest LRAAs unless
it provides a rationale (such as ensuring
geographical coverage of the
distribution system instead of clustering
all sites in a particular section of the
distribution system) for selecting other
locations. In evaluating possible Stage 2
compliance monitoring locations,
systems must consider both Stage 1
DBPR compliance data and IDSE data.
The State or primacy agency will
approve the IDSE report or request
modifications. If the State or primacy
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agency has not taken action by the date
specified in section IV.E or has not
notified the system that review is not
yet complete, systems may consider
their submission to be approved and
prepare to begin Stage 2 compliance
monitoring.
EPA has developed the Initial
Distribution System Evaluation
Guidance Manual for the Final Stage 2
Disinfectants and Disinfection
Byproducts Rule (USEPA 2006) to assist
systems with implementing each of
these requirements. This guidance may
be requested from EPA’s Safe Drinking
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Water Hotline, which may be contacted
as described under FOR FURTHER
INFORMATION CONTACT in the beginning
of this notice. This guidance manual is
also available on the EPA Web site at
https://www.epa.gov/safewater/stage2/
index.html.
2. Background and Analysis
In the Stage 2 DBPR proposal
(USEPA, 2003a), EPA proposed
requirements for systems to complete an
IDSE. The Agency based its proposal
upon the Stage 2 M–DBP Advisory
Committee recommendations in the
Agreement in Principle. The Advisory
Committee believed and EPA concurs
that maintaining Stage 1 DBPR
monitoring sites for the Stage 2 DBPR
would not accomplish the risk-targeting
objective of minimizing high DBP levels
and providing consistent and equitable
protection across the distribution
system. Most of these requirements have
not changed from the proposed rule.
The data collection requirements of
the IDSE are designed to find both high
TTHM and high HAA5 sites (see section
IV.G for IDSE monitoring requirements).
High TTHM and HAA5 concentrations
often occur at different locations in the
distribution system. The Stage 1 DBPR
monitoring sites identified as the
maximum location are selected
according to residence time. HAAs can
degrade in the distribution system in the
absence of sufficient disinfectant
residual (Baribeau et al. 2000).
Consequently, residence time is not an
ideal criterion for identifying high
HAA5 sites. In addition, maximum
residence time locations that are
associated with high TTHM levels may
not be constant due to daily or seasonal
changes in demand. The analysis of
maximum residence time completed for
the selection of Stage 1 monitoring sites
may not have been capable of detecting
these variations. The Information
Collection Rule data show that over 60
percent of the highest HAA5 LRAAs and
50 percent of the highest TTHM LRAAs
were found at sampling locations in the
distribution system other than the
maximum residence time compliance
monitoring location (USEPA 2003a).
Therefore, the method and assumptions
used to select the Information Collection
Rule monitoring sites and the Stage 1
DBPR compliance monitoring sites may
not reliably capture high DBP levels for
Stage 2 DBPR compliance monitoring
sites.
a. Standard monitoring. The Advisory
Committee recommended that systems
sample throughout the distribution
system at twice the number of locations
as required under Stage 1 and, using
these results in addition to Stage 1
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compliance data, identify high DBP
locations. Monitoring at additional sites
increases the chance of finding sites
with high DBP levels and targets both
DBPs that degrade and DBPs that form
as residence time increases in the
distribution system. EPA believes that
the required number of standard
monitoring locations plus Stage 1
monitoring results will provide an
adequate characterization of DBP levels
throughout the distribution system at a
reasonable cost. By revising Stage 2
compliance monitoring plans to target
locations with high DBPs, systems will
be required to take steps to address high
DBP levels at locations that might
otherwise have gone undetected.
The Advisory Committee
recommended that an IDSE be
performed by all community water
systems, unless the system had
sufficiently low DBP levels or is a very
small system with a simple distribution
system. EPA believes that large
nontransient noncommunity water
systems (NTNCWS) (those serving at
least 10,000 people) also have
distribution systems that require further
evaluation to determine the locations
most representative of high DBP levels
and proposed that they be required to
conduct an IDSE. Therefore, large
NTNCWS and all community water
systems are required to comply with
IDSE requirements under today’s final
rule, unless they submit a 40/30
certification or they are covered by the
very small system waiver provisions.
b. Very small system waivers. Systems
serving fewer than 500 people that have
taken samples under the Stage 1 DBPR
will receive a very small system waiver.
EPA proposed and the Advisory
Committee recommended a very small
system waiver following a State
determination that the existing Stage 1
compliance monitoring location
adequately characterizes both high
TTHM and high HAA5 for the
distribution system because many very
small systems have small or simple
distribution systems. The final rule
grants the very small system waiver to
all systems serving fewer than 500 that
have Stage 1 DBPR data. This provision
was changed from the proposal to reflect
that most very small systems that
sample under the Stage 1 DBPR have
sampling locations that are
representative of both high TTHM and
high HAA5 because most very small
systems have small and simple
distribution systems. In addition, many
very small systems are ground water
systems that typically have stable DBP
levels that tend to be lower than surface
water DBP levels. NRWA survey data
show that free chlorine residual in very
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423
small systems (serving <500) at both
average residence time and maximum
residence time locations are lower than
levels at both of those locations in larger
systems, and the change in residual
concentration between those two
locations is smaller in very small
systems compared to larger sized
systems. The magnitude of the
reduction in residual concentration
gives an indication of how much
disinfectant has reacted to form DBPs,
including TTHM and HAA5. The
smaller reduction in disinfectant
concentration between average
residence time and maximum residence
time in very small systems compared to
larger systems indicates that DBP
formation potential is probably lower in
very small systems compared to larger
systems, and the likelihood for
significant DBP variation within the
distribution system of very small
systems is low if the distribution system
is small and not complex. However,
there may be some small systems with
extended or complex distribution
systems that should be studied further
to determine new sampling locations.
For this reason, States or primacy
agencies can require any particular very
small system to conduct an IDSE. Very
small systems subject to the Stage 2
DBPR that do not have a Stage 1
compliance monitoring location may
monitor in accordance with the Stage 1
DBPR provisions to be eligible for this
waiver.
c. 40/30 certifications. Systems that
certify to their State or primacy agency
that all compliance samples taken
during eight consecutive calendar
quarters prior to the start of the IDSE
were ≤0.040 mg/L TTHM and ≤0.030
mg/L HAA5 are not required to collect
additional DBP monitoring data under
the IDSE requirements as long as the
system has no TTHM or HAA5
monitoring violations. These criteria
were developed because both EPA and
the AdvisoryCommittee determined that
these systems most likely would not
have DBP levels that exceed the MCLs.
Systems must have qualifying TTHM
and HAA5 data for eight consecutive
calendar quarters according to the
schedule in Table IV.F–2 to be eligible
for this option. Systems on reduced
monitoring that did not monitor during
the specified time period may use data
from the prior year to meet the 40/30
certification criteria. Systems that have
not previously conducted Stage 1 DBPR
compliance monitoring may begin such
monitoring to collect the data necessary
to qualify for 40/30 certification. The
certification and data supporting it must
be available to the public upon request.
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The qualifying time period for the 40/
30 certification has changed from the
proposed rule.
Under the proposed rule, the rule
language identified a specific two year
window with start and end dates. In
today’s final rule, the qualifying time
period has been changed to ‘‘eight
consecutive calendar quarters of subpart
L compliance monitoring results
beginning no earlier than * * *’’ (see
Table IV.F–2). This change was made so
that systems that have made a treatment
change within the two years prior to
rule promulgation and have collected
initial data that meet the 40/30 criteria
might have the opportunity to collect
eight consecutive quarters of qualifying
data and apply for a 40/30 certification.
This schedule change also allows
systems that have not previously
monitored under Stage 1 an opportunity
to qualify for a 40/30 certification.
Under the proposed Stage 2 DBPR,
systems that missed the deadline for
submitting a 40/30 certification would
be required to conduct either standard
monitoring or a system specific study
even if the system otherwise qualified
for the 40/30 certification. Under
today’s final rule, systems that do not
make any submission by the IDSE plan
submission deadline will still receive a
violation, but may submit a late 40/30
certification if their data meet the
requirements. This change was made so
that systems and primacy agencies do
not spend time preparing and reviewing
standard monitoring plans and IDSE
reports for systems with a low
likelihood of finding high TTHM and
HAA5 levels.
The reporting requirements for this
provision have been reduced from the
requirements in the proposed
rulemaking. In the proposal, systems
qualifying for the 40/30 certification
were required to submit all qualifying
data and provide recommendations for
Stage 2 compliance monitoring
locations. The final rule requires
systems to submit a certification that
their data meet all the requirements of
the 40/30 certification and to include
their Stage 2 compliance monitoring
recommendations in their Stage 2
monitoring plan. These changes were
made to reduce the reporting burden on
systems that qualify for the 40/30
certification and to maintain
consistency with monitoring plan
requirements under the Stage 1 DBPR.
This approach also gives systems more
time to select appropriate monitoring
sites for Stage 2 compliance monitoring.
The State or primacy agency may
request systems to submit the data, a
distribution system schematic, and/or
recommendations for Stage 2
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compliance monitoring as part of the
40/30 certification. This provision was
included to facilitate primacy agency
review of 40/30 certifications; the
additional information is only required
if requested by the primacy agency.
d. System specific studies. Advisory
Committee members recognized that
some systems have detailed knowledge
of their distribution systems by way of
ongoing hydraulic modeling and/or
existing widespread monitoring plans
(beyond that required for compliance
monitoring) that would provide
equivalent or superior monitoring site
selection information compared to
standard monitoring. Therefore, the
Advisory Committee recommended that
such systems be allowed to determine
new monitoring sites using systemspecific data such as hydraulic model
results or existing monitoring data; this
provision remains in the final rule. In
the proposed rule, the only specification
for SSSs was to identify monitoring sites
that would be equivalent or superior to
those identified under Standard
Monitoring. The final rule includes
more specific requirements on how
these studies should be completed. The
requirements in the final rule were
developed to be consistent with the
proposal, yet more specific to help
systems better understand expectations
under this provision and lessen the
chances of a study plan not being
approved.
The new modeling requirements were
developed to reflect that hydraulic
models can identify representative high
TTHM monitoring locations by
predicting hydraulic residence time in
the distribution system. Water age has
been found to correlate with TTHM
formation in the distribution system.
Consequently, for this system specific
study approach, hydraulic residence
time predicted by the model is used as
a surrogate for TTHM formation to
locate appropriate Stage 2 compliance
monitoring locations. To predict
hydraulic residence time in the
distribution system, the model must
represent most of the distribution
system and must have been calibrated
recently and appropriately to reflect
water age in the distribution system.
Requirements to reflect this are in
today’s rule. All storage facilities must
be evaluated for the calibration, and
systems using this option must submit
a graph of predicted tank levels versus
measured tank levels for the storage
facility with the highest residence time
in each pressure zone. These calibration
requirements are focused on storage
facilities because they are the largest
controlling factor for water age in the
distribution system. The calibration
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requirements reflect the fact that the
purpose of the model is to predict water
age. ICR data show that HAA5 data do
not necessarily correlate well with water
age (USEPA 2003a). Because the
purpose of the IDSE is to locate
representative high locations for both
TTHM and HAA5, one round of
monitoring must be completed at
potential Stage 2 compliance monitoring
locations to determine appropriate
HAA5 monitoring locations during the
historical high month of TTHM
concentrations. The number of locations
must be no less than would be required
under standard monitoring.
Preliminary average residence time
data are required as a part of the study
plan for systems to demonstrate that
their distribution system hydraulic
model is able to produce results for
water age throughout the distribution
system, even though calibration may not
be complete. Systems also need to
describe their plans to complete the
modeling requirements within 12
months of submitting the study plan.
These last two requirements were
developed so that States can be assured
that systems have the technical capacity
to complete their modeling
requirements by the IDSE report
deadline. If systems cannot demonstrate
that they are in a position to complete
the modeling requirements according to
the required schedule, they will be
required to complete standard
monitoring.
All new modeling requirements were
added to help systems demonstrate how
their model will fulfill the purpose and
requirements of the IDSE and to assist
primacy agencies with approval
determinations. The associated
reporting requirements were developed
to balance the needs of systems to
demonstrate that they have fulfilled the
requirements and the needs of primacy
agency reviewers to be able to
understand the work completed by the
system.
EPA has specified new requirements
for systems complete an SSS using
existing monitoring data to help systems
understand the extent of historical data
that would meet the requirements of the
IDSE. The number of required sample
locations and samples are consistent
with sampling requirements under
standard monitoring and the
recommendations made by the Advisory
Committee. The Advisory Committee
recommended that systems complete an
IDSE sample at twice the number of
sites required by the Stage 1 DBPR in
addition to Stage 1 DBPR sampling.
Because the number of required Stage 1
DBPR monitoring locations varies
within each population category under
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the Stage 1 plant-based monitoring
approach (since systems have different
numbers of plants), EPA used the
number of required Standard
Monitoring locations plus the number of
Stage 2 compliance monitoring
locations to develop minimum
requirements for the use of existing
monitoring data for the SSS. The
number of required locations and
samples are shown in Table IV.F–4.
Systems will use their Stage 1
monitoring results plus additional noncompliance or operational samples to
fulfill these requirements. Small
systems with many plants may have
been collecting a disproportionate
number of samples under the Stage 1
DBPR compared to the population based
monitoring requirements presented in
today’s rule and may have sufficient
historical data to characterize the entire
distribution system. These requirements
allow those systems to submit an SSS
based on existing Stage 1 monitoring
results, and they also accommodate
systems that have been completing
additional monitoring throughout the
distribution system.
The requirement to sample during the
historical month of high TTHM, high
HAA5, or warmest water temperature
during each year for which data were
collected was added to maintain
consistency with the standard
monitoring requirements where each
location must be sampled one time
during the peak historical month.
Samples that qualify for this SSS must
have been collected within five years of
the study plan submission date and
must reflect the current configuration of
treatment and the distribution system.
Five years was selected as a cut off for
eligible data so that all data submitted
would be reasonably representative of
current source water conditions and
DBP formation within the distribution
system. Data that are older may not
reflect current DBP formation potential
in the distribution system. Five years
prior to the submission of the study
plan also correlates with the signing of
the Agreement in Principle where the
Advisory Committee made the
recommendation for this provision.
Systems interested in using this
provision would have started eligible
monitoring after the agreement was
signed.
Systems that submit existing
monitoring data must submit all Stage 1
sample results from the beginning of the
SSS to the time when the SSS plan is
submitted. The purpose of this
requirement is to demonstrate that there
have been no significant changes in
source water quality since the first
samples were collected, especially if all
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existing monitoring results were taken
during the earliest eligible dates. Again,
these clarifications were made so that
systems could better understand the
extent of data necessary for a monitoring
plan to be deemed acceptable and be
confident that efforts to complete an
SSS would be found acceptable to the
State or primacy agency.
e. Distribution System Schematics.
EPA has considered security concerns
that may result from the requirement for
systems to submit a distribution system
schematic as part of their IDSE plan.
EPA believes that the final rule strikes
an appropriate balance between security
concerns and the need for States and
primacy agencies to be able to review
IDSE plans. EPA has developed
guidance for systems on how to submit
a distribution system schematic that
does not include sensitive information.
3. Summary of Major Comments
The Agency received significant
comments on the following issues
related to the proposed IDSE
requirements: Waiver limitations, and
State or primacy agency review of IDSE
plans.
In the proposed rule, EPA requested
comment on what the appropriate
criteria should be for States or primacy
agencies to grant very small system
waivers. Commenters responded with a
wide range of suggestions including
support for the proposal as written,
different population cut-offs, State or
primacy agency discretion on what
system size should qualify for the
waiver, and alternative waiver criteria
such as pipe length or number of
booster stations. There was no
consensus among the commenters on
what changes should be made to the
proposal for the very small system
waiver requirements. EPA did not
change the population cutoff for the
very small system waiver because
analysis of NRWA survey data also
showed that systems serving fewer than
500 had different residence times and
lower free chlorine residual
concentrations compared to other
population categories, indicating that
larger systems have different DBP
formation characteristics compared to
very small systems. Some of the
suggested changes for very small system
waiver criteria may require data that are
not readily available to systems (such as
pipe length in service) and for which
there were no specific criteria proposed
or recommended by the commenters.
Implementation of subjective very small
system waiver criteria would result in
reduced public health protection from
the rule by allowing higher DBP levels
to go undetected.
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425
In addition to addressing the very
small system waivers, commenters
suggested that different criteria should
be used for the 40/30 certification, such
as higher minimum DBP levels, cut-offs
of 40/30 as LRAAs or RAAs rather than
single sample maximums, or State or
primacy agency discretion on which
systems should qualify for 40/30
certification. There was no consensus
among the commenters on what changes
should be made to the proposal for the
40/30 certification requirements. EPA
did not change the requirements for the
40/30 certification eligibility because
the recommended alternatives were not
technically superior to the requirements
of the proposed rule. Implementation of
40/30 criteria using an LRAA or RAA
would result in reduced public health
protection from the rule by allowing
higher DBP levels to go undetected. EPA
did change the eligibility dates and
reporting requirements for the 40/30
certification to reduce the burden on the
system. Under today’s final rule, States
or primacy agencies can request TTHM
and HAA5 data as desired for a more indepth review of a system’s
qualifications.
Many commenters expressed concern
over the implementation schedule for
the IDSE. Commenters were especially
concerned that IDSE plans would be
developed and implemented prior to
State primacy, and once States receive
primacy, they might not support the
IDSE plan and would reject the results
of the completed IDSE. To address this
issue, commenters requested the
opportunity for States to review the
IDSE plans prior to systems completing
their IDSEs. In today’s rule EPA has
modified the compliance schedule for
the Stage 2 DBPR so that systems have
the opportunity to complete their IDSE
plan and have it reviewed by the
primacy agency prior to completing the
IDSE to address the concern that States
or primacy agencies may reject the
results of the completed IDSE. The
changes to the compliance schedule are
discussed further in section IV.E.
G. Monitoring Requirements and
Compliance Determination for TTHM
and HAA5 MCLs
EPA is finalizing monitoring
requirements under a population-based
approach described in this section. EPA
believes the population-based approach
will provide more representative high
DBP concentrations throughout
distribution systems than would plantbased monitoring, is equitable, and will
simplify implementation for both States
and systems. For these reasons, EPA
believes this approach is more
appropriate than the proposed plant-
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based monitoring. Detailed discussion
of the two approaches is presented in
the preamble of the proposed rule
(USEPA 2003a) and EA for today’s rule
(USEPA 2005a).
1. Today’s Rule
Today’s rule establishes TTHM and
HAA5 monitoring requirements for all
systems based on a population-based
monitoring approach instead of a plantbased approach. Under the population-
based approach, monitoring
requirements are based solely on the
retail population served and the type of
source water used and not influenced by
the number of treatment plants or entry
points in the distribution system as in
previous rules (i.e., TTHM Rule (USEPA
1979) and Stage 1 DBPR (USEPA
1998a)).
a. IDSE Monitoring. All systems
conducting IDSE standard monitoring
must collect samples during the peak
historical month for DBP levels or water
temperature; this will determine their
monitoring schedule. Table IV.G–1
contains the IDSE monitoring
frequencies and locations for all source
water and size category systems. Section
IV.F identifies other approaches by
which systems can meet IDSE
requirements.
TABLE IV.G–1.—IDSE MONITORING FREQUENCIES AND LOCATIONS
Distribution system monitoring locations 1
Source water
type
Monitoring periods and
frequency of sampling
Population size category
Total per
monitoring
period
Average
residence
time
Near entry
points
High TTHM
locations
High HAA5
locations
Subpart H
<500 consecutive systems.
<500 non-consecutive
systems.
one (during peak historical month) 2.
..........................................
2
1
....................
1
2
....................
....................
1
1
500–3,300 non-consecutive systems.
500–3,300 consecutive
systems.
four (every 90 days) ........
2
1
....................
1
....................
..........................................
2
....................
....................
1
1
3,301–9,999 .....................
10,000–49,999 .................
50,000–249,999 ...............
250,000–999,999 .............
1,000,000–4,999,999 .......
≥5,000,000 .......................
..........................................
six (every 60 days) ..........
..........................................
..........................................
..........................................
..........................................
4
8
16
24
32
40
....................
1
3
4
6
8
1
2
4
6
8
10
2
3
5
8
10
12
1
2
4
6
8
10
<500 consecutive systems.
one (during peak historical month) 2.
2
1
....................
1
....................
<500 non-consecutive
systems.
500–9,999 ........................
10,000–99,999 .................
100,000–499,999 .............
≥500,000 ..........................
..........................................
2
....................
....................
1
1
four (every 90 days) ........
..........................................
..........................................
..........................................
2
6
8
12
....................
1
1
2
....................
1
1
2
1
2
3
4
1
2
3
4
Ground
Water
1A
dual sample set (i.e., a TTHM and an HAA5 sample) must be taken at each monitoring location during each monitoring period.
peak historical month is the month with the highest TTHM or HAA5 levels or the warmest water temperature.
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2 The
b. Routine Stage 2 Compliance
Monitoring. For all systems conducting
either standard monitoring or a system
specific study, initial Stage 2
compliance monitoring locations are
based on the system’s IDSE results,
together with an analysis of a system’s
Stage 1 DBPR compliance monitoring
results. Systems receiving 40/30
certification or a very small system
waiver, and nontransient
noncommunity water systems serving
<10,000 not required to conduct an
IDSE, base Stage 2 initial compliance
monitoring locations on the system’s
Stage 1 DBPR compliance monitoring
results. Some of these systems may also
need an evaluation of distribution
system characteristics to identify
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additional monitoring locations, if
required by the transition from plantbased monitoring to population-based
monitoring.
Systems recommend Stage 2
monitoring locations generally by
arraying results of IDSE standard
monitoring (or system specific study
results) and Stage 1 compliance
monitoring by monitoring location (from
highest to lowest LRAA for both TTHM
and HAA5). Using the protocol in
§ 141.605(c) of today’s rule, systems
then select the required number of
locations. Larger systems include
existing Stage 1 monitoring locations in
order to be able to have historical
continuity for evaluating how changes
in operations or treatment affect DBP
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levels. Systems may also recommend
locations with lower levels of DBPs that
would not be picked up by the protocol
if they provide a rationale for the
recommendation. Examples of
rationales include ensuring better
distribution system or population
coverage (not having all locations in the
same area) or maintaining existing
locations with DBP levels that are nearly
as high as those that would otherwise be
selected. The State or primacy agency
will review these recommendations as
part of the review of the IDSE report
submitted by systems that conducted
standard monitoring or a system specific
study.
Table IV.G–2 contains the routine
Stage 2 TTHM and HAA5 compliance
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monitoring requirements for all systems
(both non-consecutive and consecutive
systems), as well as the protocol for
Stage 2 compliance monitoring location
selection in the IDSE report. Systems
that do not have to submit an IDSE
report (those receiving a 40/30
certification or very small system waiver
and nontransient noncommunity water
systems serving <10,000) must conduct
Stage 2 compliance monitoring as
indicated in the ‘‘Total per monitoring
period’’ column at current Stage 1
compliance monitoring locations, unless
the State or primacy agency specifically
directs otherwise. All systems are then
required to maintain and follow a Stage
2 compliance monitoring plan.
TABLE IV.G–2. ROUTINE COMPLIANCE MONITORING FREQUENCIES AND LOCATIONS
Distribution system monitoring location
Source water type
Population size category
Monitoring frequency1
Total per
monitoring
period2
Highest
TTHM locations
Highest
HAA5 locations
Existing
Subpart L
compliance
locations
Subpart H:
<500 ..................................
500–3,300 .........................
3,301–9,999 ......................
10,000–49,999 ..................
50,000–249,999 ................
250,000–999,999 ..............
1,000,000–4,999,999 ........
≥ 5,000,000 .......................
per
per
per
per
per
per
per
per
year .............................
quarter ........................
quarter ........................
quarter ........................
quarter ........................
quarter ........................
quarter ........................
quarter ........................
2
2
2
4
8
12
16
20
1
1
1
2
3
5
6
8
1
1
1
1
3
4
6
7
....................
....................
....................
1
2
3
4
5
<500 ..................................
500–9,999 .........................
10,000–99,999 ..................
100,000–499,999 ..............
≥ 500,000 ..........................
per
per
per
per
per
year .............................
year .............................
quarter ........................
quarter ........................
quarter ........................
2
2
4
6
8
1
1
2
3
3
1
1
1
2
3
....................
....................
1
1
2
Ground water:
1 All
systems must monitor during month of highest DBP concentrations.
on quarterly monitoring must take dual sample sets every 90 days at each monitoring location, except for subpart H systems serving
500–3,300. Systems on annual monitoring and subpart H systems serving 500–3,300 are required to take individual TTHM and HAA5 samples
(instead of a dual sample set) at the locations with the highest TTHM and HAA5 concentrations, respectively. Only one location with a dual sample set per monitoring period is needed if highest TTHM and HAA5 concentrations occur at the same location, and month, if monitored annually).
2 Systems
Today’s rule provides States the
flexibility to specify alternative Stage 2
compliance monitoring requirements
(but not alternative IDSE monitoring
requirements) for multiple consecutive
systems in a combined distribution
system. As a minimum under such an
approach, each consecutive system must
collect at least one sample among the
total number of samples required for the
combined distribution system and will
base compliance on samples collected
within its distribution system. The
consecutive system is responsible for
ensuring that required monitoring is
completed and the system is in
compliance. It also must document its
monitoring strategy as part of its subpart
V monitoring plan.
Consecutive systems not already
conducting disinfectant residual
monitoring under the Stage 1 DBPR
must comply with the monitoring
requirements and MRDLs for chlorine
and chloramines. States may use the
provisions of § 141.134(c) to modify
reporting requirements. For example,
the State may require that only the
consecutive system distribution system
point-of-entry disinfectant
concentration be reported to
demonstrate MRDL compliance,
although monitoring requirements may
not be reduced.
i. Reduced monitoring. Systems can
qualify for reduced monitoring, as
specified in Table IV.G–3, if the LRAA
at each location is ≤0.040 mg/L for
TTHM and ≤0.030 mg/L for HAA5 based
on at least one year of monitoring at
routine compliance monitoring
locations. Systems may remain on
reduced monitoring as long as the
TTHM LRAA is ≤0.040 mg/L and the
HAA5 LRAA is ≤0.030 mg/L at each
monitoring location for systems with
quarterly reduced monitoring. If the
LRAA at any location exceeds either
0.040 mg/L for TTHM or 0.030 mg/L for
HAA5 or if the source water annual
average TOC level, before any treatment,
exceeds 4.0 mg/L at any of the system’s
treatment plants treating surface water
or ground water under the direct
influence of surface water, the system
must resume routine monitoring. For
systems with annual or less frequent
reduced monitoring, systems may
remain on reduced monitoring as long
as each TTHM sample is ≤0.060 mg/L
and each HAA5 sample is ≤0.045 mg/L.
If the annual (or less frequent) sample
at any location exceeds either 0.060 mg/
L for TTHM or 0.045 mg/L for HAA5,
or if the source water annual average
TOC level, before any treatment,
exceeds 4.0 mg/L at any treatment plant
treating surface water or ground water
under the direct influence of surface
water, the system must resume routine
monitoring.
TABLE IV.G–3.—REDUCED MONITORING FREQUENCY
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Population size category
Monitoring frequency 1
<500 ......................
Source water type
...........................
Distribution system monitoring location per monitoring period
Subpart H:
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TABLE IV.G–3.—REDUCED MONITORING FREQUENCY—Continued
Population size category
Monitoring frequency 1
Distribution system monitoring location per monitoring period
500–3,300 .............
per year .................
3,301–9,999 ..........
per year .................
10,000–49,999 ......
per quarter ............
50,000–249,999 ....
per quarter ............
250,000–999,999 ..
per quarter ............
1,000,000–
4,999,999.
≥5,000,000 ............
per quarter ............
1 TTHM and 1 HAA5 sample: one at the location and during the quarter with
the highest TTHM single measurement, one at the location and during the
quarter with the highest HAA5 single measurement; 1 dual sample set per
year if the highest TTHM and HAA5 measurements occurred at the same
location and quarter.
2 dual sample sets: one at the location and during the quarter with the highest
TTHM single measurement, one at the location and during the quarter with
the highest HAA5 single measurement.
2 dual sample sets at the locations with the highest TTHM and highest HAA5
LRAAs.
4 dual sample sets—at the locations with the two highest TTHM and two highest HAA5 LRAAs.
6 dual sample sets—at the locations with the three highest TTHM and three
highest HAA5 LRAAs
8 dual sample sets—at the locations with the four highest TTHM and four
highest HAA5 LRAAs.
10 dual sample sets—at the locations with the five highest TTHM and five
highest HAA5 LRAAs.
<500 ......................
every third year .....
500–9,999 .............
per year .................
10,000–99,999 ......
per year .................
100,000–499,999 ..
per quarter ............
≥500,000 ...............
Source water type
per quarter ............
per quarter ............
Ground Water:
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1 Systems
1 TTHM and 1 HAA5 sample: one at the location and during the quarter with
the highest TTHM single measurement, one at the location and during the
quarter with the highest HAA5 single measurement; 1 dual sample set per
year if the highest TTHM and HAA5 measurements occurred at the same
location and quarter.
1 TTHM and 1 HAA5 sample: one at the location and during the quarter with
the highest TTHM single measurement, one at the location and during the
quarter with the highest HAA5 single measurement; 1 dual sample set per
year if the highest TTHM and HAA5 measurements occurred at the same
location and quarter.
2 dual sample sets: one at the location and during the quarter with the highest
TTHM single measurement, one at the location and during the quarter with
the highest HAA5 single measurement.
2 dual sample sets; at the locations with the highest TTHM and highest HAA5
LRAAs.
4 dual sample sets at the locations with the two highest TTHM and two highest HAA5 LRAAs.
on quarterly monitoring must take dual sample sets every 90 days.
ii. Compliance determination. A PWS
is in compliance when the annual
sample or LRAA of quarterly samples is
less than or equal to the MCLs. If an
annual sample exceeds the MCL, the
system must conduct increased
(quarterly) monitoring but is not
immediately in violation of the MCL.
The system is out of compliance if the
LRAA of the quarterly samples for the
past four quarters exceeds the MCL.
Monitoring and MCL violations are
assigned to the PWS where the violation
occurred. Several examples are as
follows:
• If monitoring results in a
consecutive system indicate an MCL
violation, the consecutive system is in
violation because it has the legal
responsibility for complying with the
MCL under State/EPA regulations. The
consecutive system may set up a
contract with its wholesale system that
details water quality delivery
specifications.
• If a consecutive system has hired its
wholesale system under contract to
monitor in the consecutive system and
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the wholesale system fails to monitor,
the consecutive system is in violation
because it has the legal responsibility
for monitoring under State/EPA
regulations.
• If a wholesale system has a
violation and provides that water to a
consecutive system, the wholesale
system is in violation. Whether the
consecutive system is in violation will
depend on the situation. The
consecutive system will also be in
violation unless it conducted
monitoring that showed that the
violation was not present in the
consecutive system.
2. Background and Analysis
EPA proposed the plant-based
approach for all systems that produce
some or all of their finished water and
the population-based monitoring
approach for systems purchasing all of
their finished water year-round. As part
of the proposal, EPA presented a
monitoring cost analysis for applying
this approach to all systems in the
Economic Analysis to better understand
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the impacts of using the populationbased approach.
The plant-based approach was
adopted from the 1979 TTHM rule and
the Stage 1 DBPR and was derived from
the generally valid assumption that, as
systems increase in size, they tend to
have more plants and increased
complexity. During the development of
the Stage 2 proposal, EPA identified a
number of issues associated with the
use of the plant-based monitoring
approach. These included: (1) Plantbased monitoring is not as effective as
population-based monitoring in
targeting locations with the highest risk;
(2) a plant-based approach can result in
disproportionate monitoring
requirements for systems serving the
same number of people (due to widely
varying numbers of plants per system);
(3) it cannot be adequately applied to
plants or consecutive system entry
points that are operated seasonally or
intermittently if an LRAA is used for
compliance due to complex
implementation and a need for repeated
transactions between the State and
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system to determine whether and how
compliance monitoring requirements
may need to be changed; (4) State
determinations of monitoring
requirements for consecutive systems
would be complicated, especially in
large combined distribution systems
with many connections between
systems; and (5) systems with multiple
disinfecting wells would have to
conduct evaluation of common aquifers
in order to avoid taking unnecessary
samples for compliance (if they did not
conduct such evaluations under Stage
1). EPA requested comment on two
approaches to address these issues: (1)
keep the plant-based monitoring
approach and add new provisions to
address specific concerns; and (2) base
monitoring requirements on source
water type and population served, in
lieu of plant-based monitoring.
The final rule’s requirements of
population-based monitoring for all
systems are based on improved public
health protection, flexibility, and
simplified implementation. For
determining monitoring requirements,
EPA’s objective was to maintain
monitoring loads consistent with Stage
1 and similar to monitoring loads
proposed for Stage 2 under a plantbased approach, using a populationbased approach to facilitate
implementation, better target high DBP
levels, and protect human health. This
leads to a more cost-effective
characterization of where high levels
occur. For the proposed rule, EPA used
1995 CWSS data to derive the number
of plants per system for calculating the
number of proposed monitoring sites
per system. During the comment period,
2000 CWSS data became available.
Compared to the 1995 CWSS, the 2000
CWSS contained questions more
relevant for determining the number of
plants in each system. Based on 2000
CWSS data, EPA has modified the
number of monitoring sites per system
for several categories (particularly for
the larger subpart H systems) to align
the median population-based
monitoring requirements with the
median monitoring requirements under
plant-based monitoring, as was
proposed.
EPA also believes that more samples
are necessary to characterize larger
systems (as defined by population) than
for smaller systems. This progressive
approach is included in Table IV.G–4.
As system size increases, the number of
samples increases to better reflect the
hydraulic complexity of these systems.
While the national monitoring burden
under the population-based approach is
slightly less than under a plant-based
approach, some larger systems with few
plants relative to system population will
take more samples per system than they
had under plant-based monitoring.
However, EPA believes that many of
these large systems with few plants have
traditionally been undermonitored (as
noted in the proposal). Systems with
more plants will see a reduction in
monitoring (e.g., small ground water
systems with multiple wells).
While population-based monitoring
requirements for ground water systems
in today’s rule remain the same as those
in the proposed rule, the final rule
consolidates ten population categories
for subpart H systems into eight
categories for ease of implementation.
As indicated in Table IV.G–4, EPA has
gone from four to three population size
categories for smaller subpart H systems
(serving fewer than 10,000 people) and
the ranges have been modified to be
consistent with those for other existing
rules (such as the Lead and Copper
Rule). This change will reduce
implementation transactional costs. For
medium and large subpart H systems
(serving at least 10,000 people), EPA has
gone from seven categories in the
proposal to five categories in final rule.
The population groups are sized so that
the ratio of maximum population to
minimum population for each of the
categories is consistent. EPA believes
that this will allow most systems to
remain in one population size category
and maintain the same monitoring
requirements within a reasonable range
of population variation over time. In
addition, it assures that systems within
a size category will not have disparate
monitoring burdens as could occur if
there were too few categories. Overall,
EPA believes that the population-based
monitoring approach allows systems to
have more flexibility to designate their
monitoring sites within the distribution
system to better target high DBP levels
and is more equitable.
To derive the number of monitoring
sites for IDSE standard monitoring, EPA
doubled the number of routine
compliance monitoring sites per system
for each size category. This is consistent
with the advice and recommendations
of the M-DBP Advisory Committee for
the IDSE. EPA has developed the Initial
Distribution System Evaluation
Guidance Manual for the Final Stage 2
Disinfectants and Disinfection
Byproducts Rule (USEPA 2006) to assist
systems in choosing IDSE monitoring
locations, including criteria for selecting
monitoring.
TABLE IV.G–4.—COMPARISON OF MONITORING LOCATIONS PER SYSTEM FOR STAGE 2 ROUTINE COMPLIANCE
MONITORING WITH PLANT-BASED AND POPULATION-BASED APPROACHES
Ratio of
maximum
population
to minimum
population
Plant-based
approach*
Number of plants per system (Based on 2000
CWSS data)
Calculated number of sites
per system for plant-based
approach
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<500 ..................................................................
500–3,300 .........................................................
3,301–9,999 ......................................................
10,000–49,999 ..................................................
50,000–249,999 ................................................
250,000–<1 million ............................................
1 million–<5 million ...........................................
≥5 million ...........................................................
# Sites per
plant
Median
Mean
Based on
median #
plants per
system
Based on
mean #
plants per
system
A
Population category
Number of
sampling
periods per
year
B
C
D
E=B*C
F=B*D
....................
6.6
3
5
5
4
5
....................
1
4
4
4
4
4
4
4
**1
**1
2
4
4
4
4
4
1
1
1
1
1
2
4
4
1.21
1.22
1.56
1.37
1.83
2.53
3.62
4.33
1
1
2
4
4
8
16
16
1.2
1.2
3.1
5.5
7.3
10.1
14.5
17.3
Number of
monitoring
sites per
system for
pop-based
approach
G
**1
**1
2
4
8
12
16
20
* As in the proposal.
** System is required to take individual TTHM and HAA5 samples at the locations with the highest TTHM and HAA5 concentrations, respectively, if highest TTHM
and HAA5 concentrations do not occur at the same location.
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Note: To determine the number of routine compliance monitoring sites per population category, EPA took these steps: (1) Maintaining about the same sampling
loads in the nation as required under the plant-based approach, but basing on population rather than number of plants to better target high DBP levels in distribution
systems and facilitate implementation; (2) The number of monitoring sites per plant under the plant-based approach (Column B) were multiplied by the number of
plants per system (Columns C and D) to calculate the number of monitoring sites per system under the plant-based approach (Columns E and F in terms of median
and mean, respectively); and (3) The number of monitoring sites per system under the population-based approach were derived with adjustments to keep categories
consistent and to maintain an even incremental trend as the population size category increases (Column G).
3. Summary of Major Comments
EPA received significant support for
applying the population-based approach
to all systems. EPA also received
comments concerning the specific
requirements in a population-based
approach.
Excessive Sampling Requirements.
Several commenters believed that the
proposed sampling requirements were
excessive (especially in the larger
population categories for subpart H
systems) and that some individual
systems would be required to sample
more under the population-based
approach than the plant-based
approach. EPA recognizes that a small
fraction of systems in some categories
will have to take more samples under
the population-based approach than the
plant-based approach because their
number of plants is substantially less
than the national median or mean.
However, the number of samples
required under the Stage 1 DBPR for
these systems may not have been
sufficient to determine the
concentrations of DBPs throughout the
distribution system of these systems. On
the other hand, systems with many
plants may have taken excessive
samples under the Stage 1 DBPR that
were not necessary to appropriately
determine DBP levels throughout the
distribution system. Consequently, the
total number of samples taken
nationally will be comparable to the
Stage 1 DBPR, but will better target DBP
risks in individual distribution systems.
Consecutive systems. Some
commenters noted that a consecutive
system may need to take more samples
than its associated wholesale system.
Under today’s rule, all systems,
including consecutive systems, must
monitor based on retail population
served. Thus, large consecutive systems
will take more samples than a smaller
wholesale system. The population-based
monitoring approach will allow the
samples to better represent the DBP
concentrations consumed by the
population associated with the sampling
locations and to understand the DBP
concentrations reaching consumers.
There is also a provision that allows
States to specify alternative monitoring
requirements for a consecutive system
in a combined distribution system (40
CFR 142.16(m)(3)). This special primacy
condition allows the State to establish
monitoring requirements that account
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for complicated distribution system
relationships, such as where
neighboring systems buy from and sell
to each other regularly throughout the
year. In this case, water may pass
through multiple consecutive systems
before it reaches a user. Another
example would be a large group of
interconnected systems that have a
complicated combined distribution
system. This approach also allows the
combined distribution system to
concentrate IDSE and Stage 2
monitoring sites in the system with the
highest known DBP concentrations,
while assigning fewer sample sites to
systems with low DBP concentrations.
Population Size Categories. Some
commenters recommended fewer
population categories for subpart H
systems (those using surface water or
ground water under the direct influence
of surface water as a source) than
proposed while others recommended
more. Today’s rule has fewer categories
than proposed. However, EPA believes
that further reduction of the number of
population size categories will not
reflect the fact that the number of plants
and complexity of distribution systems
(and DBP exposure) tend to increase as
the population served increases. As a
result, the population served by a large
system in one particular category would
receive much less protection from the
DBP risks than a smaller system in the
same size category. On the other hand,
too many categories with smaller
population ranges would result in
frequent category and requirement shifts
as population fluctuates. Much greater
implementation effort would be needed
for those systems without much benefit
in DBP exposure knowledge.
Population Definition. Some
commenters supported use of the
population of a combined distribution
system (i.e., the wholesale and
consecutive systems should be
considered a single system for
monitoring purposes) while others
preferred use of the retail population for
each individual system (i.e., wholesale
systems and consecutive systems are
considered separately). Today’s final
rule uses the retail population for each
individual system. EPA chose this
approach for today’s rule because of the
complexity involved in making
implementation decisions for
consecutive systems. Using the retail
population to determine requirements
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eases the complexity by specifying
minimum system-level requirements;
simplicity is essential for meeting the
implementation schedule in today’s
rule. If monitoring requirements were
determined by the combined
distribution system population, many
implementation problems would occur.
Some of these problems would have the
potential to impact public health
protection. For example, States or
primacy agencies would have to decide
how to allocate IDSE distribution
system samples (where and how much
to monitor in individual PWSs) in a
complicated combined distribution
system with many systems, multiple
sources, multiple treatment plants, and
varying water demand and with limited
understanding of DBP levels throughout
the combined distribution system. This
would have to happen shortly after rule
promulgation in order to meet the
schedule. For example, some
consecutive systems buy water
seasonally (in times of high water
demand) or buy from more than one
wholesale system (with the volume
purchased based on many factors). The
State or primacy agency would find it
difficult to properly assign a limited
number of IDSE monitoring locations
(especially since there are States where
many consecutive systems have no DBP
data) to adequately reflect DBP levels in
such a system, as well as throughout the
combined distribution system.
EPA believes that assigning
compliance monitoring requirements
appropriately throughout the combined
distribution system requires a case-bycase determination based on factors
such as amount and percentage of
finished water provided; whether
finished water is provided seasonally,
intermittently, or full-time; and
improved DBP occurrence information.
Since the IDSE will provide improved
DBP occurrence information throughout
the combined distribution system,
States may consider modifications to
Stage 2 compliance monitoring
requirements for consecutive systems on
a case-by-case basis as allowed by
§ 141.29 or under the special primacy
condition at § 142.16(m)(3) by taking all
these factors into consideration. In
making these case-by-case
determinations, the State will be able to
use its system-specific knowledge, along
with the IDSE results, to develop an
appropriate monitoring plan for each
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system within the combined
distribution system.
Changes to monitoring plans.
Commenters requested more specific
language regarding how IDSE and Stage
2 monitoring plans should be updated
as a result of treatment or population
changes in the distribution system.
Changes to IDSE plans should not be
necessary since the State or primacy
agency will have reviewed those plans
shortly before the system must conduct
the IDSE and the reviewed plan should
identify such issues. EPA provided a
process in the Stage 2 DBPR proposal
for updating monitoring plans for
systems that have significant changes to
treatment or in the distribution system
after they complete their IDSE. This
process remains in today’s rule, with an
added requirement that systems must
consult with the State or primacy
agency to determine whether the
changes are necessary and appropriate
prior to implementing changes to their
Stage 2 monitoring plan.
In addition, the State or primacy
agency may require a system to revise
its IDSE plan, IDSE report, or Stage 2
monitoring plan at any time. This
change was made so that systems could
receive system-specific guidance from
the State or primacy agency on the
appropriate revisions to the Stage 2
monitoring plan. Regulatory language
regarding changes that might occur is
not appropriate because any
modifications would be system-specific
and a national requirement is not
capable of addressing these systemspecific issues.
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H. Operational Evaluation
Requirements Initiated by TTHM and
HAA5 Levels
A system that is in full compliance
with the Stage 2 DBPR LRAA MCL may
still have individual DBP measurements
that exceed the Stage 2 DBPR MCLs,
since compliance is based on individual
DBP measurements at a location
averaged over a four-quarter period.
EPA and the Advisory Committee were
concerned about these higher levels of
DBPs. This concern was clearly
reflected in the Agreement in Principle,
which states, ‘‘. . . significant
excursions of DBP levels will sometimes
occur, even when systems are in full
compliance with the enforceable
MCL. . .’’.
Today’s final rule addresses this
concern by requiring systems to conduct
operational evaluations that are initiated
by operational evaluation levels
identified in Stage 2 DBPR compliance
monitoring and to submit an operational
evaluation report to the State.
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1. Today’s Rule
Today’s rule defines the Stage 2 DBP
operational evaluation levels that
require systems to conduct operational
evaluations. The Stage 2 DBP
operational evaluation levels are
identified using the system’s Stage 2
DBPR compliance monitoring results.
The operational evaluation levels for
each monitoring location are
determined by the sum of the two
previous quarters’ TTHM results plus
twice the current quarter’s TTHM result,
at that location, divided by 4 to
determine an average and the sum of the
two previous quarters’ HAA5 results
plus twice the current quarter’s HAA5
result, at that location, divided by 4 to
determine an average. If the average
TTHM exceeds 0.080 mg/L at any
monitoring location or the average
HAA5 exceeds 0.060 mg/L at any
monitoring location, the system must
conduct an operational evaluation and
submit a written report of the
operational evaluation to the State.
Operational evaluation levels
(calculated at each monitoring location)
IF (Q1 + Q2 + 2Q3)/4> MCL, then the
system must conduct an operational
evaluation
where:
Q3 = current quarter measurement
Q2 = previoius quarter measurement
Q1 = quarter before previous quarter
measurement
MCL = Stage 2 MCL for TTHM (0.080
mg/l) or Stage 2 MCL for HAA5 (0.060
mg/L)
The operational evaluation includes
an examination of system treatment and
distribution operational practices,
including changes in sources or source
water quality, storage tank operations,
and excess storage capacity, that may
contribute to high TTHM and HAA5
formation. Systems must also identify
what steps could be considered to
minimize future operational evaluation
level exceedences. In cases where the
system can identify the cause of DBP
levels that resulted in the operational
evaluation, based on factors such as
water quality data, plant performance
data, and distribution system
configuration the system may request
and the State may allow limiting the
evaluation to the identified cause. The
State must issue a written determination
approving limiting the scope of the
operational evaluation. The system must
submit their operational evaluation
report to the State for review within 90
days after being notified of the
analytical result that initiates the
operational evaluation. Requesting
approval to limit the scope of the
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431
operational evaluation does not extend
the schedule (90 days after notification
of the analytical result) for submitting
the operational evaluation report.
2. Background and Analysis
The Stage 2 DBPR proposal outlined
three components of the requirements
for significant excursions (definition,
system evaluation and excursion
report). In response to public comments,
the term ‘‘significant excursion’’ has
been replaced by the term ‘‘operational
evaluation level’’ in today’s rule. The
evaluation and report components
remain the same as those outlined in the
proposed rule for significant excursions.
However, the scope of the evaluation
and report components of the
operational evaluation has also been
modified from the proposed significant
excursion evaluation components based
on public comments.
In the Stage 2 DBPR proposal, States
were to define criteria to identify
significant excursions rather than using
criteria defined by EPA. Concurrent
with the Stage 2 DBPR proposal, EPA
issued draft guidance (USEPA 2003e)
for systems and States that described
how to determine whether a significant
excursion has occurred, using several
different options. The rule proposal
specifically requested public comment
on the definition of a significant
excursion, whether it should be defined
by the State or nationally, and the scope
of the evaluation.
After reviewing comments on the
Stage 2 DBPR proposal, EPA determined
that DBP levels initiating an operational
evaluation should be defined in the
regulation to ensure national
consistency. Systems were concerned
with the evaluation requirements being
initiated based on criteria that might not
be consistent nationally. Also, many
States believed the requirement for
States to define criteria to initiate an
evaluation would be difficult for States
to implement.
Under today’s rule, EPA is defining
operational evaluation levels with an
algorithm based on Stage 2 DBPR
compliance monitoring results. These
operational evaluation levels will act as
an early warning for a possible MCL
violation in the following quarter. This
early warning is accomplished because
the operational evaluation requirement
is initiated when the system assumes
that the current quarter’s result is
repeated and this will result in an MCL
violation. This early identification
allows the system to act to prevent the
violation.
Today’s rule also modifies the scope
of an operational evaluation. EPA has
concluded that the source of DBP levels
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that would initiate an operational
evaluation can potentially be linked to
a number of factors that extend beyond
distribution system operations.
Therefore, EPA believes that evaluations
must include a consideration of
treatment plant and other system
operations rather than limiting the
operational evaluation to only the
distribution system, as proposed.
Because the source of the problem could
be associated with operations in any of
these system components (or more than
one), an evaluation that provides
systems with valuable information to
evaluate possible modifications to
current operational practices (e.g. water
age management, source blending) or in
planning system modifications or
improvements (e.g. disinfection
practices, tank modifications,
distribution looping) will reduce DBP
levels initiating an operational
evaluation. EPA also believes that State
review of operational evaluation reports
is valuable for both States and systems
in their interactions, particularly when
systems may be in discussions with or
requesting approvals from the State for
system improvements. Timely reviews
of operational evaluation reports will be
valuable for States in reviewing other
compliance submittals and will be
particularly valuable in reviewing and
approving any proposed source,
treatment or distribution system
modifications for a water system. Under
today’s rule, systems must submit a
written report of the operational
evaluation to the State no later than 90
days after being notified of the DBP
analytical result initiating an
operational evaluation. The written
operational evaluation report must also
be made available to the public upon
request.
3. Summary of Major Comments
EPA received comments both in favor
of and opposed to the proposed
evaluation requirements. While some
commenters felt that the evaluation
requirements should not be a part of the
Stage 2 DBPR until there was more
information regarding potential health
effects correlated to specific DBP levels,
other commenters felt that the existing
health effects data were sufficient to
warrant strengthening the proposed
requirements for an evaluation. Today’s
final rule requirements are consistent
with the Agreement in Principle
recommendations.
Some commenters noted that health
effects research on DBPs is insufficient
to identify a level at which health
effects occur and were concerned that
the proposed significant excursion
requirements placed an emphasis on
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DBP levels that might not be warranted
rather than on system operational issues
and compliance with Stage 2 DBPR
MCLs.
Basis. The proposed requirements for
significant excursion evaluations were
not based upon health effects, but rather
were intended to be an indicator of
operational performance. To address
commenter’s concerns and to emphasize
what EPA believes should initiate a
comprehensive evaluation of system
operations that may result in elevated
DBP levels and provide a proactive
procedure to address compliance with
Stage 2 DBP LRAA MCLs , EPA has
replaced the term ‘‘significant
excursion’’ used in the Stage 2 DBPR
proposal with the term ‘‘operational
evaluation level’’ in today’s rule.
Definition of the operational
evaluation levels. The majority of
commenters stated that EPA should
define the DBP levels initiating an
operational evaluation (‘‘significant
excursion’’ in the proposal) in the
regulation to ensure national
consistency rather than requiring States
to develop their own criteria (as was
proposed). Commenters suggested
several definitions, including a single
numerical limit and calculations
comparing previous quarterly DBP
results to the current quarter’s result.
Commenters that recommended a single
numerical limit felt that such an
approach was justified by the available
health effects information, while other
commenters felt available heath effects
information did not support a single
numerical limit. Commenters
recommended that any definition be
easy to understand and implement.
EPA agrees with commenter
preference for national criteria to
initiate an operational evaluation. The
DBP levels initiating an operational
evaluation in today’s rule consider
routine operational variations in
distribution systems, are simple for
water systems to calculate, and
minimize the implementation burden
on States. They also provide an early
warning to help identify possible future
MCL violations and allow the system to
take proactive steps to remain in
compliance. EPA emphasizes, as it did
in the proposal and elsewhere in this
notice, that health effects research is
insufficient to identify a level at which
health effects occur, and thus today’s
methodology for initiating operational
evaluation is not based upon health
effects, but rather is intended as an
indicator of operational performance.
Scope of an evaluation. Some
commenters felt that the scope of an
evaluation initiated by locational DBP
levels should be limited to the
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distribution systems, as in the proposal.
Others felt that the treatment processes
should be included in the evaluation,
noting that these can be significant in
the formation of DBPs.
The Agency agrees with commenters
that treatment processes can be a
significant factor in DBP levels initiating
an operational evaluation and that a
comprehensive operational evaluation
should address treatment processes. In
cases where the system can clearly
identify the cause of the DBP levels
initiating an operational evaluation
(based on factors such as water quality
data, plant performance data,
distribution system configuration, and
previous evaluations) the State may
allow the system to limit the scope of
the evaluation to the identified cause. In
other cases, it is appropriate to evaluate
the entire system, from source through
treatment to distribution system
configuration and operational practices.
Timing for completion and review of
the evaluation report. While some
commenters agreed that the evaluation
report should be reviewed as part of the
sanitary survey process (as proposed),
many commenters felt that the time
between sanitary surveys (up to five
years) minimized the value of the
evaluation report in identifying both the
causes of DBP levels initiating an
operational evaluation and in possible
changes to prevent recurrence.
Moreover, a number of commenters felt
that the evaluation report was important
enough to warrant a separate submittal
and State review rather than have the
evaluation report compete with other
priorities during a sanitary survey.
The Agency agrees that completion
and State review of evaluation reports
on a three or five year sanitary survey
cycle, when the focus of the evaluation
is on what may happen in the next
quarter, would allow for an
unreasonable period of time to pass
between the event initiating the
operational evaluation and completion
and State review of the report. This
would diminish the value of the
evaluation report for both systems and
States, particularly when systems may
be in discussions with or requesting
approval for treatment changes from
States, and as noted above, the focus of
the report is on what may occur in the
next quarter. EPA believes that timely
reviews of evaluation reports by States
is important, would be essential for
States in understanding system
operations and reviewing other
compliance submittals, and would be
extremely valuable in reviewing and
approving any proposed source,
treatment or distribution system
modifications for a water system.
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Having the evaluation information on an
ongoing basis rather than a delayed
basis would also allow States to
prioritize their resources in scheduling
and reviewing particular water system
operations and conditions as part of any
on-site system review or oversight.
Therefore, today’s rule requires that
systems complete the operational
evaluation and submit the evaluation
report to the State within 90 days of the
occurrence.
I. MCL, BAT, and Monitoring for
Bromate
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1. Today’s Rule
Today EPA is confirming that the
MCL for bromate for systems using
ozone remains at 0.010 mg/L as an RAA
for samples taken at the entrance to the
distribution system as established by the
Stage 1 DBPR. Because the MCL remains
the same, EPA is not modifying the
existing bromate BAT. EPA is changing
the criterion for a system using ozone to
qualify for reduced bromate monitoring
from demonstrating low levels of
bromide to demonstrating low levels of
bromate.
2. Background and Analysis
a. Bromate MCL. Bromate is a
principal byproduct from ozonation of
bromide-containing source waters. As
described in more detail in the Stage 2
DBPR proposal (USEPA 2003a), more
stringent bromate MCL has the potential
to decrease current levels of microbial
protection, impair the ability of systems
to control resistant pathogens like
Cryptosporidium, and increase levels of
DBPs from other disinfectants that may
be used instead of ozone. EPA
considered reducing the bromate MCL
from 0.010 mg/L to 0.005 mg/L as an
annual average but concluded that many
systems using ozone to inactivate
microbial pathogens would have
significant difficulty maintaining
bromate levels at or below 0.005 mg/L.
In addition, because of the high doses
required, the ability of systems to use
ozone to meet Cryptosporidium
treatment requirements under the
LT2ESWTR would be diminished if the
bromate MCL was decreased from 0.010
to 0.005 mg/L; higher doses will
generally lead to greater bromate
formation. After evaluation under the
risk-balancing provisions of section
1412(b)(5) of the SDWA, EPA concluded
that the existing MCL was justified. EPA
will review the bromate MCL as part of
the six-year review process and
determine whether the MCL should
remain at 0.010 mg/L or be reduced to
a lower level. As a part of that review,
EPA will consider the increased
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utilization of alternative technologies,
such as UV, and whether the risk/risk
concerns reflected in today’s rule, as
well as in the LT2ESWTR, remain valid.
b. Criterion for reduced bromate
monitoring. Because more sensitive
bromate methods are now available,
EPA is requiring a new criterion for
reduced bromate monitoring. In the
Stage 1 DBPR, EPA required ozone
systems to demonstrate that source
water bromide levels, as a running
annual average, did not exceed 0.05 mg/
L. EPA elected to use bromide as a
surrogate for bromate in determining
eligibility for reduced monitoring
because the available analytical method
for bromate was not sensitive enough to
quantify levels well below the bromate
MCL of 0.010 mg/L.
EPA approved several new analytical
methods for bromate that are far more
sensitive than the existing method as
part of today’s rule. Since these methods
can measure bromate to levels of 0.001
mg/L or lower, EPA is replacing the
criterion for reduced bromate
monitoring (source water bromide
running annual average not to exceed
0.05 mg/L) with a bromate running
annual average not to exceed 0.0025 mg/
L.
In the past, EPA has often set the
criterion for reduced monitoring
eligibility at 50% of the MCL, which
would be 0.005 mg/L. However, the
MCL for bromate will remain at 0.010
mg/L, representing a risk level of 2×10/
b 2×10¥4, 10¥4 and 10¥6 (higher than
EPA’s usual excess cancer risk range of
10¥4 to 10¥6) because of risk tradeoff
considerations) (USEPA 2003a).
EPA believes that the decision for
reduced monitoring is separate from
these risk tradeoff considerations. Risk
tradeoff considerations influence the
selection of the MCL, while reduced
monitoring requirements are designed to
ensure that the MCL, once established,
is reliably and consistently achieved.
Requiring a running annual average of
0.0025 mg/L for the reduced monitoring
criterion allows greater confidence that
the system is achieving the MCL and
thus ensuring public health protection.
3. Summary of Major Comments
Commenters supported both the
retention of the existing bromate MCL
and the modified reduced monitoring
criterion.
J. Public Notice Requirements
1. Today’s Rule
Today’s rule does not alter existing
public notification language for TTHM,
HAA5 or TOC, which are listed under
40 CFR 141.201–141.210 (Subpart Q).
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433
2. Background and Analysis
EPA requested comment on including
language in the proposed rule
concerning potential reproductive and
developmental health effects. EPA
believes this is an important issue
because of the large population exposed
(58 million women of child-bearing age;
USEPA 2005a) and the number of
studies that, while not conclusive, point
towards a potential risk concern. While
EPA is not including information about
reproductive and developmental health
effects in public notices at this time, the
Agency plans to reconsider whether to
include this information in the future.
As part of this effort, EPA intends to
support research to assess
communication strategies on how to
best provide this information.
The responsibilities for public
notification and consumer confidence
reports rest with the individual system.
Under the Public Notice Rule (Part 141
subpart Q) and Consumer Confidence
Report Rule (Part 141 subpart O), the
wholesale system is responsible for
notifying the consecutive system of
analytical results and violations related
to monitoring conducted by the
wholesale system. Consecutive systems
are required to conduct appropriate
public notification after a violation
(whether in the wholesale system or the
consecutive system). In their consumer
confidence report, consecutive systems
must include results of the testing
conducted by the wholesale system
unless the consecutive system
conducted equivalent testing (as
required in today’s rule) that indicated
the consecutive system was in
compliance, in which case the
consecutive system reports its own
compliance monitoring results.
3. Summary of Major Comments
EPA requested and received many
comments on the topic of including
public notification language regarding
potential reproductive and
developmental effects. A number of
comments called for including
reproductive and developmental health
effects language to address the potential
health concerns that research has
shown. Numerous comments also
opposed such language due to
uncertainties in the underlying science
and the implications such language
could have on public trust of utilities.
EPA agrees on the importance of
addressing possible reproductive and
developmental health risks. However,
given the uncertainties in the science
and our lack of knowledge of how to
best communicate undefined risks, a
general statement about reproductive
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and developmental health effects is
premature at this time. The Agency
needs to understand how best to
characterize and communicate these
risks and what to do to follow up any
such communication. The public
deserves accurate, timely, relevant, and
understandable communication. The
Agency will continue to follow up on
this issue with additional research,
possibly including a project to work
with stakeholders to assess risk
communication strategies.
Some comments also suggested
leaving the choice of language up to the
water server. EPA believes that this
strategy would cause undue confusion
to both the PWS and the public.
Commenters generally agreed that
both wholesale and consecutive systems
that conduct monitoring be required to
report their own analytical results as
part of their CCRs. One commenter
requested clarification of consecutive
system public notification requirements
when there is a violation in the
wholesale system but the consecutive
system data indicate that it meets DBP
MCLs.
Although EPA requires consecutive
systems to conduct appropriate public
notification of violations (whether in the
wholesale or consecutive system), there
may be cases where the violation may
only affect an isolated portion of the
distribution system. Under the public
notification rule, the State may allow
systems to limit distribution of the
notice to the area that is out of
compliance if the system can
demonstrate that the violation occurred
in a part of the distribution system that
is ‘‘physically or hydraulically isolated
from other parts of the distribution
system.’’ This provision remains in
place. As for a consecutive system
whose wholesale system is in violation,
the consecutive system is not required
to conduct public notification if DBP
levels in the consecutive system are in
compliance.
K. Variances and Exemptions
1. Today’s Rule
States may grant variances in
accordance with sections 1415(a) and
1415(e) of the SDWA and EPA’s
regulations. States may grant
exemptions in accordance with section
1416(a) of the SDWA and EPA’s
regulations.
2. Background and Analysis
a. Variances. The SDWA provides for
two types of variances—general
variances and small system variances.
Under section 1415(a)(1)(A) of the
SDWA, a State that has primary
enforcement responsibility (primacy), or
EPA as the primacy agency, may grant
general variances from MCLs to those
public water systems of any size that
cannot comply with the MCLs because
of characteristics of the raw water
sources. The primacy agency may grant
general variances to a system on
condition that the system install the best
technology, treatment techniques, or
other means that EPA finds available
and based upon an evaluation
satisfactory to the State that indicates
that alternative sources of water are not
reasonably available to the system. At
the time this type of variance is granted,
the State must prescribe a compliance
schedule and may require the system to
implement additional control measures.
Furthermore, before EPA or the State
may grant a general variance, it must
find that the variance will not result in
an unreasonable risk to health (URTH)
to the public served by the public water
system. In today’s final rule, EPA is
specifying BATs for general variances
under section 1415(a) (see section IV.D).
Section 1415(e) authorizes the
primacy agency to issue variances to
small public water systems (those
serving fewer than 10,000 people) where
the primacy agent determines (1) that
the system cannot afford to comply with
an MCL or treatment technique and (2)
that the terms of the variances will
ensure adequate protection of human
health (63 FR 43833, August 14, 1998)
(USEPA 1998c). These variances may
only be granted where EPA has
determined that there is no affordable
compliance technology and has
identified a small system variance
technology under section 1412(b)(15) for
the contaminant, system size and source
water quality in question. As discussed
below, small system variances under
section 1415(e) are not available because
EPA has determined that affordable
compliance technologies are available.
The 1996 Amendments to the SDWA
identify three categories of small public
water systems that need to be addressed:
(1) Those serving a population of 3301–
10,000; (2) those serving a population of
500–3300; and (3) those serving a
population of 25–499. The SDWA
requires EPA to make determinations of
available compliance technologies for
each size category. A compliance
technology is a technology that is
affordable and that achieves compliance
with the MCL and/or treatment
technique. Compliance technologies can
include point-of-entry or point-of-use
treatment units. Variance technologies
are only specified for those system size/
source water quality combinations for
which there are no listed affordable
compliance technologies.
Using its current National
Affordability Criteria, EPA has
determined that multiple affordable
compliance technologies are available
for each of the three system sizes
(USEPA 2005a), and therefore did not
identify any variance treatment
technologies. The analysis was
consistent with the current methodology
used in the document ‘‘National-Level
Affordability Criteria Under the 1996
Amendments to the Safe Drinking Water
Act’’ (USEPA 1998d) and the ‘‘Variance
Technology Findings for Contaminants
Regulated Before 1996’’ (USEPA 1998e).
However, EPA is currently reevaluating
its national-level affordability criteria
and has solicited recommendations
from both the NDWAC and the SAB as
part of this review. EPA intends to
apply the revised criteria to the Stage 2
DBPR once they have been finalized for
the purpose of determining whether to
enable States to give variances. Thus,
while the analysis of Stage 2 household
costs will not change, EPA’s
determination regarding the availability
of affordable compliance technologies
for the different categories of small
systems may.
b. Affordable Treatment Technologies
for Small Systems. The treatment trains
considered and predicted to be used in
EPA’s compliance forecast for systems
serving under 10,000 people, are listed
in Table IV.K–1.
TABLE IV.K–1.—TECHNOLOGIES CONSIDERED AND PREDICTED TO BE USED IN COMPLIANCE FORECAST FOR SMALL
SYSTEMS
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SW Water Plants
•
•
•
•
•
GW Water Plants
Switching to chloramines as a residual disinfectant .............................
Chlorine dioxide (not for systems serving fewer than 100 people) ......
UV .........................................................................................................
Ozone (not for systems serving fewer than 100 people) .....................
Micro-filtration/Ultra-filtration .................................................................
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•
•
•
•
•
Switching to chloramines as a residual disinfectant
UV
Ozone (not for systems serving fewer than 100 people)
GAC20
Nanofiltration
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TABLE IV.K–1.—TECHNOLOGIES CONSIDERED AND PREDICTED TO BE USED IN COMPLIANCE FORECAST FOR SMALL
SYSTEMS—Continued
SW Water Plants
GW Water Plants
• GAC20.
• GAC20 + Advanced disinfectants.
• Integrated Membranes.
Note: Italicized technologies are those predicted to be used in the compliance forecast.
Source: Exhibits 5.11b and 5.14b, USEPA 2005a.
The household costs for these
technologies were compared against the
EPA’s current national-level
affordability criteria to determine the
affordable treatment technologies. The
Agency’s national level affordability
criteria were published in the August 6,
1998 Federal Register (USEPA 1998d).
A complete description of how this
analysis was applied to Stage 2 DBPR is
given in Section 8.3 of the Economic
Analysis (USEPA 2005a).
Of the technologies listed in Table
IV.K–1, integrated membranes with
chloramines, GAC20 with advanced
oxidants, and ozone are above the
affordability threshold in the 0 to 500
category. No treatment technologies are
above the affordability threshold in the
500 to 3,300 category or the 3,300 to
10,000 category. As shown in the
Economic Analysis for systems serving
fewer than 500 people, 14 systems are
predicted to use GAC20 with advanced
disinfectants, one system is predicted to
use integrated membranes, and no
systems are predicted to use ozone to
comply with the Stage 2 DBPR (USEPA
2005a). However, several alternate
technologies are affordable and likely
available to these systems. In some
cases, the compliance data for these
systems under the Stage 2 DBPR will be
the same as under the Stage 1 DBPR
(because many systems serving fewer
than 500 people will have the same
single sampling site under both rules);
these systems will have already
installed the necessary compliance
technology to comply with the Stage 1
DBPR. It is also possible that less costly
technologies such as those for which
percentage use caps were set in the
decision tree may actually be used to
achieve compliance (e.g., chloramines,
UV). Thus, EPA believes that
compliance by these systems will be
affordable.
As shown in Table IV.K–2, the cost
model predicts that some households
served by very small systems will
experience household cost increases
greater than the available expenditure
margins as a result of adding advanced
technology for the Stage 2 DBPR
(USEPA 2005a). This prediction may be
overestimated because small systems
may have other compliance alternatives
available to them besides adding
treatment, which were not considered in
the model. For example, some of these
systems currently may be operated on a
part-time basis; therefore, they may be
able to modify the current operational
schedule or use excessive capacity to
avoid installing a costly technology to
comply with the Stage 2 DBPR. The
system also may identify another water
source that has lower TTHM and HAA5
precursor levels. Systems that can
identify such an alternate water source
may not have to treat that new source
water as intensely as their current
source, resulting in lower treatment
costs. Systems may elect to connect to
a neighboring water system. While
connecting to another system may not
be feasible for some remote systems,
EPA estimates that more than 22 percent
of all small water systems are located
within metropolitan regions (USEPA
2000f) where distances between
neighboring systems will not present a
prohibitive barrier. Low-cost
alternatives to reduce total
trihalomethanes (TTHM) and haloacetic
acid (HAA5) levels also include
distribution system modifications such
as flushing distribution mains more
frequently, looping to prevent dead
ends, and optimizing storage to
minimize retention time. More
discussion of household cost increases
is presented in Section VI.E and the
Economic Analysis (USEPA 2005a).
TABLE IV.K–2.—DISTRIBUTION OF HOUSEHOLD UNIT TREATMENT COSTS FOR PLANTS ADDING TREATMENT
Systems size
(population
seved)
Number of
households
served by
plants adding treatment (Percent of all
households
subject to
the Stage 2
DBPR)
0–500 ................
501–3,300 .........
3,301–10,000 ....
43045(3)
205842 (4)
342525 (5)
Mean annual household cost increase
A
Median annual household cost increase
B
C
$201.55
$58.41
$37.05
Available
expenditure
margin ($/
hh/yr)
F
Number of
groundwater
plants with
annual cost
increases
greater than
the available expenditure
margin
Total number of plants
with annual
cost increases
greater than
the available expenditure
margin
I
J=H+I
G
D
$299.01
$29.96
$14.59
Number of
surface
water plants
with annual
cost increases
greater than
the available expenditure
margin
H
95th Percentile annual household cost increase
E
90th Percentile annual household cost increase
Number of
households
with annual
cost increases
greater than
the available expenditure
margin
$299.01
$75.09
$55.25
$414.74
$366.53
$200.05
$733
$724
$750
964
0
0
15
9
0
0
0
0
15
0
0
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Notes: Household unit costs represent treatment costs only. All values in year 2003 dollars.
Source: Exhibit 8.4c, USEPA 2005a.
c. Exemptions. Under section 1416(a),
EPA or a State that has primary
enforcement responsibility (primacy)
may exempt a public water system from
any requirements related to an MCL or
treatment technique of an NPDWR, if it
finds that (1) due to compelling factors
(which may include economic factors
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such as qualification of the PWS as
serving a disadvantaged community),
the PWS is unable to comply with the
requirement or implement measures to
develop an alternative source of water
supply; (2) the exemption will not result
in an unreasonable risk to health; and;
(3) the PWS was in operation on the
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effective date of the NPDWR, or for a
system that was not in operation by that
date, only if no reasonable alternative
source of drinking water is available to
the new system; and (4) management or
restructuring changes (or both) cannot
reasonably result in compliance with
the Act or improve the quality of
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drinking water. If EPA or the State
grants an exemption to a public water
system, it must at the same time
prescribe a schedule for compliance
(including increments of progress or
measures to develop an alternative
source of water supply) and
implementation of appropriate control
measures that the State requires the
system to meet while the exemption is
in effect. Under section 1416(b)(2)(A),
the schedule prescribed shall require
compliance as expeditiously as
practicable (to be determined by the
State), but no later than 3 years after the
effective date for the regulations
established pursuant to section
1412(b)(10). For public water systems
which do not serve more than a
population of 3,300 and which need
financial assistance for the necessary
improvements, EPA or the State may
renew an exemption for one or more
additional two-year periods, but not to
exceed a total of 6 years, if the system
establishes that it is taking all
practicable steps to meet the
requirements above. A public water
system shall not be granted an
exemption unless it can establish that
either: (1) the system cannot meet the
standard without capital improvements
that cannot be completed prior to the
date established pursuant to section
1412(b)(10); (2) in the case of a system
that needs financial assistance for the
necessary implementation, the system
has entered into an agreement to obtain
financial assistance pursuant to section
1452 or any other Federal or state
program; or (3) the system has entered
into an enforceable agreement to
become part of a regional public water
system.
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3. Summary of Major Comments
Several commenters agreed with the
proposal not to list variances
technologies for the Stage 2 DBPR. One
commenter requested that EPA modify
the methodology used to assess
affordability. As mentioned earlier, EPA
is currently reevaluating its nationallevel affordability criteria and has
solicited recommendations from both
the NDWAC and the SAB as part of this
review. EPA intends to apply the
revised criteria to the Stage 2 DBPR for
the purpose of determining whether to
enable States to give variances.
L. Requirements for Systems to Use
Qualified Operators
EPA believes that systems that must
make treatment changes to comply with
requirements to reduce microbiological
risks and risks from disinfectants and
disinfection byproducts should be
operated by personnel who are qualified
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to recognize and respond to problems.
Subpart H systems were required to be
operated by qualified operators under
the SWTR (§ 141.70). The Stage 1 DBPR
added requirements for all disinfected
systems to be operated by qualified
personnel who meet the requirements
specified by the State, which may differ
based on system size and type. The rule
also requires that States maintain a
register of qualified operators (40 CFR
141.130(c)). While the Stage 2 DBPR
requirements do not supercede or
modify the requirement that disinfected
systems be operated by qualified
operators, such personnel play an
important role in delivering drinking
water that meets Stage 2 MCLs to the
public. States should also review and
modify, as required, their qualification
standards to take into account new
technologies (e.g., ultraviolet (UV)
disinfection) and new compliance
requirements (including simultaneous
compliance and consecutive system
requirements). EPA received only one
comment on this topic; the commenter
supported the need for a qualified
operator.
M. System Reporting and Recordkeeping
Requirements
1. Today’s Rule
Today’s Stage 2 DBPR, consistent
with the existing system reporting and
recordkeeping regulations under 40 CFR
141.134 (Stage 1 DBPR), requires public
water systems (including consecutive
systems) to report monitoring data to
States within ten days after the end of
the compliance period. In addition,
systems are required to submit the data
required in § 141.134. These data are
required to be submitted quarterly for
any monitoring conducted quarterly or
more frequently, and within ten days of
the end of the monitoring period for less
frequent monitoring. As with other
chemical analysis data, the system must
keep the results for 10 years.
In addition to the existing Stage 1
reporting requirements, today’s rule
requires systems to perform specific
IDSE-related reporting to the primacy
agency, except for systems serving fewer
than 500 for which the State or primacy
agency has waived this requirement.
Required reporting includes submission
of IDSE monitoring plans, 40/30
certification, and IDSE reports. This
reporting must be accomplished on the
schedule specified in the rule (see
§ 141.600(c)) and discussed in section
IV.E of today’s preamble. System
submissions must include the elements
identified in subpart U and discussed
further in section IV.F of today’s
preamble. These elements include
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recommended Stage 2 compliance
monitoring sites as part of the IDSE
report.
Systems must report compliance with
Stage 2 TTHM and HAA5 MCLs (0.080
mg/LTTHM and 0.060 mg/L HAA5, as
LRAAs) according to the schedules
specified in §§ 141.620 and 141.629 and
discussed in section IV.E of today’s
preamble. Reporting for DBP
monitoring, as described previously,
will remain generally consistent with
current public water system reporting
requirements (§ 141.31 and § 141.134);
systems will be required to calculate
and report each LRAA (instead of the
system’s RAA) and each individual
monitoring result (as required under the
Stage 1 DBPR). Systems will also be
required to provide a report to the State
about each operational evaluation
within 90 days, as discussed in section
IV.H. Reports and evaluations must be
kept for 10 years and may prove
valuable in identifying trends and
recurring issues.
2. Summary of Major Comments
EPA requested comment on all system
reporting and recordkeeping
requirements. Commenters generally
supported EPA’s proposed
requirements, but expressed concern
about two specific issues. The first issue
was the data management and tracking
difficulties that States would face if EPA
finalized a monitoring approach which
had both plant-based and populationbased requirements, as was proposed.
Since today’s rule contains only
population-based monitoring
requirements, this concern is no longer
an issue. See section IV.G in today’s
preamble for further discussion.
The second concern related to
reporting associated with the IDSE.
Commenters who supported an
approach other than the IDSE for
determining Stage 2 compliance
monitoring locations did not support
IDSE-related reporting. The IDSE
remains a key component of the final
rule; thus, EPA has retained IDSErelated reporting. However, the Agency
has modified both the content and the
timing of the reporting to reduce the
burden. See sections IV.F and IV.E,
respectively, of today’s preamble for
further discussion.
N. Approval of Additional Analytical
Methods
1. Today’s Rule
EPA is taking final action to:
(1) allow the use of 13 methods
published by the Standard Methods
Committee in Standard Methods for the
Examination of Water and Wastewater,
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20th edition, 1998 (APHA 1998) and 12
methods in Standard Methods Online.
(2) approve three methods published
by American Society for Testing and
Materials International.
(3) approve EPA Method 327.0
Revision 1.1 (USEPA 2005h) for daily
monitoring of chlorine dioxide and
chlorite, EPA Method 552.3 (USEPA
2003f) for haloacetic acids (five)
(HAA5), EPA Methods 317.0 Revision 2
(USEPA 2001c) and 326.0 (USEPA 2002)
for bromate, chlorite, and bromide, EPA
Method 321.8 (USEPA 2000g) for
bromate only, and EPA Method 415.3
Revision 1.1 (USEPA 2005l) for total
organic carbon (TOC) and specific
ultraviolet absorbance (SUVA).
(4) update the citation for EPA
Method 300.1 (USEPA 2000h) for
bromate, chlorite, and bromide.
(5) standardize the HAA5 sample
holding times and the bromate sample
preservation procedure and holding
time.
(6) add the requirement to remove
inorganic carbon prior to determining
TOC or DOC, remove the specification
of type of acid used for TOC/DOC
sample preservation; and require that
TOC samples be preserved at the time
of collection.
(7) clarify which methods are
approved for magnesium hardness
determinations (40 CFR 141.131 and
141.135).
2. Background and Analysis
The Stage 1 Disinfectants and
Disinfection Byproducts Rule (Stage 1
DBPR) was promulgated on December
16, 1998 (USEPA 1998a) and it included
approved analytical methods for DBPs,
disinfectants, and DBP precursors.
Additional analytical methods became
available subsequent to the rule and
were proposed in the Stage 2
Disinfectants and Disinfection
Byproducts Rule (Stage 2 DBPR)
(USEPA 2003a). These methods are
applicable to monitoring that is required
under the Stage 1 DBPR. After the Stage
2 DBPR proposal, analytical methods for
additional drinking water contaminants
were proposed for approval in a
Methods Update Rule proposal (USEPA
2004). The Stage 2 DBPR and Methods
Update Rule proposals both included
changes in the same sections of the CFR.
EPA decided to make all the changes to
§ 141.131 as part of the Stage 2 DBPR
and the remainder of the methods that
were proposed with the Stage 2 DBPR
will be considered as part of the
Methods Update Rule, which will be
finalized at a later date. Two ASTM
methods, D 1253–86(96) and D 1253–03,
that were proposed in the Methods
Update Rule, are being approved for
measuring chlorine residual as part of
today’s action.
Minor corrections have been made in
two of the methods that were proposed
in the Stage 2 DBPR. In today’s rule, the
Agency is approving EPA Method 327.0
(Revision 1.1, 2005) which corrects
three typographical errors in the
proposed method.
EPA is also approving EPA Method
415.3 (Revision 1.1, 2005), which does
not contain the requirement that
samples for the analysis of TOC must be
received within 48 hours of sample
collection.
A summary of the methods that are
included in today’s rule is presented in
Table IV.N–1.
TABLE IV.N–1. ANALYTICAL METHODS APPROVED IN TODAY’S RULE
Analyte
Standard methods 20th
edition
EPA method
Standard methods online
Other
§ 141.131—Disinfection Byproducts
HAA5 ..................................
Bromate .............................
Chlorite (monthly or daily)
Chlorite (daily) ....................
552.3 .................................
317.0, Revision 2.0 ...........
321.8 .................................
326.0 .................................
317.0, Revision 2.0 ...........
326.0 .................................
327.0, Revision 1.1 ...........
6251 B ..............................
...........................................
6251 B–94 ........................
...........................................
ASTM D 6581–00
...........................................
...........................................
ASTM D 6581–00
4500–ClO2 E .....................
4500–ClO2 E–00 ...............
§ 141.131—Disinfectants
Chlorine (free, combined,
total).
...........................................
Chlorine (total) ...................
...........................................
Chlorine (free) ....................
Chlorine Dioxide ................
...........................................
327.0, Revision 1.1 ...........
4500–Cl D .........................
4500–Cl F .........................
4500–Cl G .........................
4500–Cl E .........................
4500–Cl I ..........................
4500–Cl H .........................
4500–ClO2 D .....................
4500–ClO2 E .....................
4500–Cl D–00 ...................
4500–Cl F–00 ...................
4500–Cl G–00 ...................
4500–Cl E–00 ...................
4500–Cl I–00 ....................
4500–Cl H–00 ...................
4500–ClO2 E–00 ...............
ASTM D 1253–86(96)
ASTM D 1253–03
...........................................
...........................................
ASTM D 6581–00
5310 B ..............................
5310 C ..............................
5310 D ..............................
5910 B ..............................
...........................................
5310 B–00 ........................
5310 C–00 ........................
5310 D–00 ........................
5910 B–00 ........................
...........................................
§ 141.131—Other parameters
TOC/DOC ..........................
317.0, Revision 2.0 ...........
326.0 .................................
415.3, Revision 1.1 ...........
UV254 ..................................
SUVA .................................
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Bromide ..............................
415.3, Revision 1.1 ...........
415.3, Revision 1.1 ...........
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O. Laboratory Certification and
Approval
1. PE Acceptance Criteria
a. Today’s rule. Today’s rule
maintains the requirements of
laboratory certification for laboratories
performing analyses to demonstrate
compliance with MCLs and all other
analyses to be conducted by approved
parties. It revises the acceptance criteria
for performance evaluation (PE) studies
which laboratories must pass as part of
the certification program. The new
acceptance limits are effective 60 days
after promulgation. Laboratories that
were certified under the Stage 1 DBPR
PE acceptance criteria will be subject to
the new criteria when it is time for them
to analyze their annual DBP PE
sample(s). Today’s rule also requires
that TTHM and HAA5 analyses that are
performed for the IDSE or systemspecific study be conducted by
laboratories certified for those analyses.
TABLE IV.O–1.—PERFORMANCE EVALUATION (PE) ACCEPTANCE CRITERIA
Acceptance
limits (percent of true
value)
DBP
TTHM
Chloroform .............................................................................
±20
±20
±20
±20
Dichloroacetic Acid ................................................................
Trichloroacetic Acid ...............................................................
Monobromoacetic Acid ..........................................................
Dibromoacetic Acid ...............................................................
Chlorite .........................................................................................
Bromate ........................................................................................
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Bromodichloromethane .........................................................
Dibromochloromethane .........................................................
Bromoform .............................................................................
HAA5
Monochloroacetic Acid ..........................................................
±40
±40
±40
±40
±30
±30
b. Background and analysis. The Stage
1 DBPR (USEPA 1998a) specified that in
order to be certified the laboratory must
pass an annual performance evaluation
(PE) sample approved by EPA or the
State using each method for which the
laboratory wishes to maintain
certification. The acceptance criteria for
the DBP PE samples were set as
statistical limits based on the
performance of the laboratories in each
study. This was done because EPA did
not have enough data to specify fixed
acceptance limits.
Subsequent to promulgation of the
Stage 1 DBPR, EPA was able to evaluate
data from PE studies conducted during
the Information Collection Rule (USEPA
1996) and during the last five general
Water Supply PE studies. Based on the
evaluation process as described in the
proposed Stage 2 DBPR (USEPA 2003a),
EPA determined that fixed acceptance
limits could be established for the DBPs.
Today’s action replaces the statistical PE
acceptance limits with fixed limits
effective one year after promulgation.
c. Summary of major comments. Four
commenters supported the fixed
acceptance criteria as presented in the
proposed rule. One requested that a
minimum concentration be set for each
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±40
Comments
Laboratory must meet all 4 individual THM acceptance limits in
order to successfully pass a PE sample for TTHM
Laboratory must meet the acceptance limits for 4 out of 5 of the
HAA5 compounds in order to successfully pass a PE sample
for HAA5
DBP in the PE studies, so that
laboratories would not be required to
meet tighter criteria in the PE study than
they are required to meet with the
minimum reporting level (MRL) check
standard. EPA has addressed this
concern by directing the PE sample
suppliers to use concentrations no less
than 10 µg/L for the individual THM
and HAAs, 100 µg/L for chlorite, and 7
µg/L for bromate in PE studies used for
certifying drinking water laboratories.
Two commenters requested that the
effective date for the new PE acceptance
criteria be extended from 60 days to 180
days, because they felt that 60 days was
not enough time for laboratories to meet
the new criteria. EPA realized from
those comments that the original intent
of the proposal was not clearly
explained; the 60 days was to be the
deadline for when the PE providers
must change the acceptance criteria that
are used when the studies are
conducted. Laboratories would have to
meet the criteria when it is time for
them to analyze their annual PE samples
in order to maintain certification.
Depending upon when the last PE
sample was analyzed, laboratories could
have up to one year to meet the new
criteria. In order to eliminate this
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confusion, EPA has modified the rule
language to allow laboratories one year
from today’s date to meet the new PE
criteria.
2. Minimum Reporting Limits
a. Today’s rule. EPA is establishing
regulatory minimum reporting limits
(MRLs) for compliance reporting of
DBPs by Public Water Systems. These
regulatory MRLs (Table IV.O–2) also
define the minimum concentrations that
must be reported as part of the
Consumer Confidence Reports (40 CFR
§ 141.151(d)). EPA is incorporating
MRLs into the laboratory certification
program for DBPs by requiring
laboratories to include a standard near
the MRL concentration as part of the
calibration curve for each DBP and to
verify the accuracy of the calibration
curve at the MRL concentration by
analyzing an MRL check standard with
a concentration less than or equal to
110% of the MRL with each batch of
samples. The measured DBP
concentration for the MRL check
standard must be ±50% of the expected
value, if any field sample in the batch
has a concentration less than 5 times the
regulatory MRL.
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439
TABLE IV.O–2.—REGULATORY MINIMUM REPORTING LEVELS
Minimum reporting level
(mg/L) 1
DBP
TTHM 2
Chloroform ......................................................
Bromodichloromethane ..................................
Dibromochloromethane ..................................
Bromoform ......................................................
HAA5 2
Monochloroacetic Acid ...................................
Dichloroacetic Acid .........................................
Trichloroacetic Acid ........................................
Monobromoacetic Acid ...................................
Dibromoacetic Acid ........................................
Chlorite ..................................................................
0.0020
0.0010
0.0010
0.0010
0.0010
0.020
Bromate .................................................................
0.0050 or 0.0010
Comments
0.0010
0.0010
0.0010
0.0010
Applicable to monitoring as prescribed in § 141.132(b)(2)(i)(B)
and (b)(2)(ii).
Laboratories that use EPA Methods 317.0 Revision 2.0, 326.0 or
321.8 must meet a 0.0010 mg/L MRL for bromate.
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1 The calibration curve must encompass the regulatory minimum reporting level (MRL) concentration. Data may be reported for concentrations
lower than the regulatory MRL as long as the precision and accuracy criteria are met by analyzing an MRL check standard at the lowest reporting limit chosen by the laboratory. The laboratory must verify the accuracy of the calibration curve at the MRL concentration by analyzing an
MRL check standard with a concentration less than or equal to 110% of the MRL with each batch of samples. The measured concentration for
the MRL check standard must be ±50% of the expected value, if any field sample in the batch has a concentration less than 5 times the regulatory MRL. Method requirements to analyze higher concentration check standards and meet tighter acceptance criteria for them must be met in
addition to the MRL check standard requirement.
2 When adding the individual trihalomethane or haloacetic acid concentrations to calculate the TTHM or HAA5 concentrations, respectively, a
zero is used for any analytical result that is less than the MRL concentration for that DBP, unless otherwise specified by the State.
b. Background and analysis. EPA
proposed to establish regulatory MRLs
for DBPs in order to define expectations
for reporting compliance monitoring
data to the Primacy Agencies and in the
Consumer Confidence Reports. The
proposed MRLs were generally based on
those used during the Information
Collection Rule (USEPA 1996), because
an analysis of the quality control data
set from the Information Collection Rule
(Fair et al. 2002) indicated that
laboratories are able to provide
quantitative data down to those
concentrations.
EPA also proposed that laboratories
be required to demonstrate ability to
quantitate at the MRL concentrations by
analyzing an MRL check standard and
meeting accuracy criteria on each day
that compliance samples are analyzed.
Three public commenters noted that
meeting the accuracy requirement for
the MRL check standard did not
contribute to the quality of the data in
cases in which the concentration of a
DBP in the samples was much higher
than the MRL. For example, if
chloroform concentrations are always
greater than 0.040 mg/L in a water
system’s samples, then verifying
accurate quantitation at 0.0010 mg/L is
unnecessary and may require the
laboratory to dilute samples or maintain
two calibration curves in order to
comply with the requirement. EPA has
taken this into consideration in today’s
rule and has adjusted the requirement
accordingly. EPA is maintaining the
requirement for all laboratories to
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analyze the MRL check standard, but
the laboratory is only required to meet
the accuracy criteria (±50%) if a field
sample has a concentration less than
five times the regulatory MRL
concentration.
EPA proposed a regulatory MRL of
0.200 mg/L for chlorite, because data
from the Information Collection Rule
indicated that most samples would
contain concentrations greater than
0.200 mg/L (USEPA 2003c). EPA also
took comment on a lower MRL of 0.020
mg/L. Commenters were evenly divided
concerning which regulatory MRL
concentration should be adopted in the
final rule. EPA has decided to set the
chlorite regulatory MRL at 0.020 mg/L
in today’s rule. This decision was based
on two factors. First, the approved
analytical methods for determining
compliance with the chlorite MCL can
easily support an MRL of 0.020 mg/L.
More importantly, since the proposal,
EPA has learned that water systems that
have low chlorite concentrations in
their water have been obtaining data on
these low concentrations from their
laboratories and have been using these
data in their Consumer Confidence
Reports. Setting the MRL at 0.020 mg/
L is reflective of current practices in
laboratories and current data
expectations by water systems.
c. Summary of major comments.
There were no major comments.
P. Other Regulatory Changes
As part of today’s action, EPA has
included several ‘‘housekeeping’’
actions to remove sections of Part 141
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that are no longer effective. These
sections have been superceded by new
requirements elsewhere in Part 141.
Sections 141.12 (Maximum
contaminant levels for total
trihalomethanes) and 141.30 (Total
trihalomethanes sampling, analytical
and other requirements) were
promulgated as part of the 1979 TTHM
Rule. These sections have been
superceded in their entirety by § 141.64
(Maximum contaminant levels for
disinfection byproducts) and subpart L
(Disinfectant Residuals, Disinfection
Byproducts, and Disinfection Byproduct
Precursors), respectively, as of
December 31, 2003. Also, § 141.32
(Public notification) has been
superceded by subpart Q (Public
Notification of Drinking Water
Violations), which is now fully in effect.
Section 553 of the Administrative
Procedure Act, 5 U.S.C. 553(b)(B),
provides that, when an agency for good
cause finds that notice and public
procedure are impracticable,
unnecessary, or contrary to the public
interest, the agency may issue a rule
without providing prior notice and an
opportunity for public comment. In
addition to updating methods, this rule
also makes minor corrections to the
National Primary Drinking Water
Regulations, specifically the Public
Notification tables (Subpart Q,
Appendices A and B). Two final
drinking water rules (66 FR 6976 and 65
FR 76708) inadvertently added new
endnotes to two existing tables using the
same endnote numbers. This rule
corrects this technical drafting error by
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renumbering the endnote citations in
these two tables. Thus, additional notice
and public comment is not necessary.
EPA finds that this constitutes ‘‘good
cause’’ under 5 U.S.C. 553(b)(B). For the
same reasons, EPA is making this rule
change effective upon publication. 5
U.S.C. 553(d)(3).
V. State Implementation
A. Today’s Rule
This section describes the regulations
and other procedures and policies States
must adopt to implement today’s rule.
States must continue to meet all other
conditions of primacy in 40 CFR Part
142. To implement the Stage 2 DBPR,
States must adopt revisions to the
following:
—§ 141.2—Definitions
—§ 141.33—Record maintenance;
—§ 141.64—Maximum contaminant
levels for disinfection byproducts;
—subpart L—Disinfectant Residuals,
Disinfection Byproducts, and
Disinfection Byproduct Precursors;
—subpart O, Consumer Confidence
Reports;
—subpart Q, Public Notification of
Drinking Water Violations;
—new subpart U, Initial Distribution
System Evaluation; and
—new subpart V, Stage 2 Disinfection
Byproducts Requirements.
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1. State Primacy Requirements for
Implementation Flexibility
In addition to adopting basic primacy
requirements specified in 40 CFR part
142, States are required to address
applicable special primacy conditions.
Special primacy conditions pertain to
specific regulations where
implementation of the rule involves
activities beyond general primacy
provisions. The purpose of these special
primacy requirements in today’s rule is
to ensure State flexibility in
implementing a regulation that (1)
applies to specific system configurations
within the particular State and (2) can
be integrated with a State’s existing
Public Water Supply Supervision
Program. States must include these ruledistinct provisions in an application for
approval or revision of their program.
These primacy requirements for
implementation flexibility are discussed
in this section.
To ensure that a State program
includes all the elements necessary for
an effective and enforceable program
under today’s rule, a State primacy
application must include a description
of how the State will implement a
procedure for modifying consecutive
system and wholesale system
monitoring requirements on a case-by-
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case basis, if a State will use the
authority to modify monitoring
requirements under this special primacy
condition.
2. State Recordkeeping Requirements
Today’s rule requires States to keep
additional records of the following,
including all supporting information
and an explanation of the technical
basis for each decision:
—very small system waivers.
—IDSE monitoring plans.
—IDSE reports and 40/30
certifications, plus any
modifications required by the State.
—operational evaluations conducted
by the system.
3. State Reporting Requirements
Today’s rule has no new State
reporting requirements.
4. Interim Primacy
States that have primacy for every
existing NPDWR already in effect may
obtain interim primacy for this rule,
beginning on the date that the State
submits the application for this rule to
USEPA, or the effective date of its
revised regulations, whichever is later.
A State that wishes to obtain interim
primacy for future NPDWRs must obtain
primacy for today’s rule. As described
in Section IV.F, EPA expects to work
with States to oversee the individual
distribution system evaluation process
that begins shortly after rule
promulgation.
5. IDSE Implementation
As discussed in section IV.E, many
systems will be performing certain IDSE
activities prior to their State receiving
primacy. During that period, EPA will
act as the primacy agency, but will
consult and coordinate with individual
States to the extent practicable and to
the extent that States are willing and
able to do so. In addition, prior to
primacy, States may be asked to assist
EPA in identifying and confirming
systems that are required to comply
with certain IDSE activities. Once the
State has received primacy, it will
become responsible for IDSE
implementation activities.
B. Background and Analysis
SDWA establishes requirements that a
State or eligible Indian Tribe must meet
to assume and maintain primary
enforcement responsibility (primacy) for
its PWSs. These requirements include
the following activities: (1) Adopting
drinking water regulations that are no
less stringent than Federal drinking
water regulations; (2) adopting and
implementing adequate procedures for
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enforcement; (3) keeping records and
making reports available on activities
that EPA requires by regulation; (4)
issuing variances and exemptions (if
allowed by the State), under conditions
no less stringent than allowed under
SDWA; and (5) adopting and being
capable of implementing an adequate
plan for the provisions of safe drinking
water under emergency situations.
40 CFR part 142 sets out the specific
program implementation requirements
for States to obtain primacy for the
public water supply supervision
program as authorized under SDWA
section 1413. In addition to adopting
basic primacy requirements specified in
40 CFR Part 142, States may be required
to adopt special primacy provisions
pertaining to specific regulations where
implementation of the rule involves
activities beyond general primacy
provisions. States must include these
regulation specific provisions in an
application for approval of their
program revision.
The current regulations in 40 CFR
142.14 require States with primacy to
keep various records, including the
following: analytical results to
determine compliance with MCLs,
MRDLs, and treatment technique
requirements; PWS inventories; State
approvals; enforcement actions; and the
issuance of variances and exemptions.
Today’s final rule requires States to
keep additional records, including all
supporting information and an
explanation of the technical basis for
decisions made by the State regarding
today’s rule requirements. The State
may use these records to identify trends
and determine whether to limit the
scope of operational evaluations. EPA
currently requires in 40 CFR 142.15 that
States report to EPA information such as
violations, variance and exemption
status, and enforcement actions; today’s
rule does not add additional reporting
requirements or modify existing
requirements.
On April 28, 1998, EPA amended its
State primacy regulations at 40 CFR
142.12 to incorporate the new process
identified in the 1996 SDWA
Amendments for granting primary
enforcement authority to States while
their applications to modify their
primacy programs are under review (63
FR 23362, April 28, 1998) (USEPA
1998f). The new process grants interim
primary enforcement authority for a
new or revised regulation during the
period in which EPA is making a
determination with regard to primacy
for that new or revised regulation. This
interim enforcement authority begins on
the date of the primacy application
submission or the effective date of the
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new or revised State regulation,
whichever is later, and ends when EPA
makes a final determination. However,
this interim primacy authority is only
available to a State that has primacy
(including interim primacy) for every
existing NPDWR in effect when the new
regulation is promulgated. States that
have primacy for every existing NPDWR
already in effect may obtain interim
primacy for this rule and a State that
wishes to obtain interim primacy for
future NPDWRs must obtain primacy for
this rule.
EPA is aware that due to the
complicated wholesale systemconsecutive system relationships that
exist nationally, there will be cases
where the standard monitoring
framework will be difficult to
implement. Therefore, States may
develop, as a special primacy condition,
a program under which the State can
modify monitoring requirements for
consecutive systems. These
modifications must not undermine
public health protection and all
systems, including consecutive systems,
must comply with the TTHM and HAA5
MCLs based on the LRAA at each
compliance monitoring location. Each
consecutive system must have at least
one compliance monitoring location.
However, such a program allows the
State to establish monitoring
requirements that account for
complicated distribution system
relationships, such as where
neighboring systems buy from and sell
to each other regularly throughout the
year, water passes through multiple
consecutive systems before it reaches a
user, or a large group of interconnected
systems have a complicated combined
distribution system. EPA has developed
a guidance manual to address these and
other consecutive system issues.
C. Summary of Major Comments
Public comment generally supported
the special primacy requirements in the
August 11, 2003 proposal, and many
commenters expressed appreciation for
the flexibility the special primacy
requirements provided to States.
Many commenters expressed concern
about EPA as the implementer instead
of the State, given the existing
relationship between the State and
system. EPA agrees that States perform
an essential role in rule implementation
and intends to work with States to the
greatest extent possible, consistent with
the rule schedule promulgated today.
EPA believes that pre-promulgation
coordination with States, changes in the
final rule strongly supported by States
(e.g., population-based monitoring
instead of plant-based monitoring), and
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the staggered rule schedule will
facilitate State involvement in preprimacy implementation.
Many commenters also requested that
the State have more flexibility to grant
sampling waivers and exemptions. EPA
believes that it has struck a reasonable
balance among competing objectives in
granting State flexibility. State
flexibility comes at a resource cost and
excessive system-by-system flexibility
could overwhelm State resources. Also,
EPA believes that much of the
monitoring and water quality
information a State would need to
properly consider whether a waiver is
appropriate is generally not available
and, if available, difficult to evaluate.
VI. Economic Analysis
This section summarizes the
Economic Analysis for the Final Stage 2
Disinfectants and Disinfection
Byproducts Rule (Economic Analysis
(EA)) (USEPA 2005a). The EA is an
evaluation of the benefits and costs of
today’s final rule and other regulatory
alternatives the Agency considered.
Specifically, this evaluation addresses
both quantified and non-quantified
benefits to PWS consumers, including
the general population and sensitive
subpopulations. Costs are presented for
PWSs, States, and consumer
households. Also included is a
discussion of potential risks from other
contaminants, uncertainties in benefit
and cost estimates, and a summary of
major comments on the EA for the
proposed Stage 2 DBPR.
EPA relied on data from several
epidemiologic and toxicologic studies,
the Information Collection Rule (ICR),
and other sources, along with analytical
models and input from technical
experts, to understand DBP risk,
occurrence, and PWS treatment changes
that will result from today’s rule.
Benefits and costs are presented as
annualized values using social discount
rates of three and seven percent. The
time frame used for benefit and cost
comparisons is 25 years—approximately
five years account for rule
implementation and 20 years for the
average useful life of treatment
technologies.
EPA has prepared this EA to comply
with the requirements of SDWA,
including the Health Risk Reduction
and Cost Analysis required by SDWA
section 1412(b)(3)(C), and Executive
Order 12866, Regulatory Planning and
Review. The full EA is available in the
docket for today’s rule, which is
available online as described in the
ADDRESSES section. The full document
provides detailed explanations of the
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analyses summarized in this section and
additional analytical results.
A. Regulatory Alternatives Considered
The Stage 2 DBPR is the second in a
set of rules that address public health
risks from DBPs. EPA promulgated the
Stage 1 DBPR to decrease average
exposure to DBPs and mitigate
associated health risks—compliance
with TTHM and HAA5 MCLs is based
on averaging concentrations across the
distribution system. In developing the
Stage 2 DBPR, EPA sought to identify
and further reduce remaining risks from
exposure to chlorinated DBPs.
The regulatory options EPA
considered for the Stage 2 DBPR are the
direct result of a consensus rulemaking
process (Federal Advisory Committee
Act (FACA) process) that involved
various drinking water stakeholders (see
Section III for a description of the FACA
process). The Advisory Committee
considered the following key questions
during the negotiation process for the
Stage 2 DBPR:
• What are the remaining health risks
after implementation of the Stage 1
DBPR?
• What are approaches to addressing
these risks?
• What are the risk tradeoffs that need
to be considered in evaluating these
approaches?
• How do the estimated costs of an
approach compare to reductions in peak
DBP occurrences and overall DBP
exposure for that approach?
The Advisory Committee considered
DBP occurrence estimates to be
important in understanding the nature
of public health risks. Although the ICR
data were collected prior to
promulgation of the Stage 1 DBPR, they
were collected under a similar sampling
strategy. The data support the concept
that a system could be in compliance
with the RAA Stage 1 DBPR MCLs of
0.080 mg/L and 0.060 mg/L for TTHM
and HAA5, respectively, and yet have
points in the distribution system with
either periodically or consistently
higher DBP levels.
Based on these findings, the Advisory
Committee discussed an array of
alternatives to address disproportionate
risk within distribution systems.
Alternative options included lowering
DBP MCLs, revising the method for
MCL compliance determination e.g.,
requiring individual sampling locations
to meet the MCL as an LRAA or
requiring that no samples exceed the
MCL), and combinations of both. The
Advisory Committee also considered the
associated technology changes and costs
for these alternatives. After narrowing
down options, the Advisory Committee
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primarily focused on four types of
alternative MCL scenarios. These are the
alternatives EPA evaluated in the EA, as
follows:
Preferred Alternative
—MCLs of 0.080 mg/L for TTHM and
0.060 mg/L for HAA5 as LRAAs
—Bromate MCL remaining at 0.010
mg/L
Alternative 1
—MCLs of 0.080 mg/L for TTHM and
0.060 mg/L for HAA5 as LRAAs
—Bromate MCL of 0.005 mg/L
Alternative 2
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—MCLs of 0.080 mg/L for TTHM and
0.060 mg/L for HAA5 as absolute
maximums for individual
measurements
—Bromate MCL remaining at 0.010
mg/L
Alternative 3
—MCLs of 0.040 mg/L for TTHM and
0.030 mg/L for HAA5 as RAAs
—Bromate MCL remaining at 0.010
mg/L.
Figure VI.A–1 shows how compliance
would be determined under each of the
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TTHM/HAA5 alternatives described and
the Stage 1 DBPR for a hypothetical
large surface water system. This
hypothetical system has one treatment
plant and measures TTHM in the
distribution system in four locations per
quarter (the calculation methodology
shown would be the same for HAA5).
Ultimately, the Advisory Committee
recommended the Preferred Alternative
in combination with an IDSE
requirement (discussed in Section IV.F).
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B. Analyses That Support Today’s Final
Rule
EPA’s goals in designing the Stage 2
DBPR were to protect public health by
reducing peak DBP levels in the
distribution system while maintaining
microbial protection. As described
earlier, the Stage 1 DBPR reduces
overall average DBP levels, but specific
locations within distribution systems
can still experience relatively high DBP
concentrations. EPA believes that high
DBP concentrations should be reduced
due to the potential association of DBPs
with cancer, as well as reproductive and
developmental health effects.
EPA analyzed the benefits and costs
of the four regulatory alternatives
presented in the previous section.
Consistent with the recommendations of
the Advisory Committee, EPA is
establishing the preferred alternative to
achieve the Agency’s goals for the Stage
2 DBPR. The following discussion
summarizes EPA’s analyses that support
today’s final rule. This discussion
explains how EPA predicted water
quality and treatment changes,
estimated benefits and costs, and
assessed the regulatory alternatives.
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1. Predicting Water Quality and
Treatment Changes
Water quality and treatment data from
the ICR were used in predicting
treatment plant technology changes (i.e.
compliance forecasts) and reductions in
DBP exposure resulting from the Stage
2 DBPR. Because ICR data were gathered
prior to Stage 1 DBPR compliance
deadlines, EPA first accounted for
treatment changes resulting from the
Stage 1 DBPR. Benefit and cost
estimates for the Stage 2 DBPR reflect
changes following compliance with the
Stage 1 DBPR.
The primary model used to predict
changes in treatment and reductions in
DBP levels was the Surface Water
Analytical Tool (SWAT), which EPA
developed using results from the ICR.
SWAT results were applied directly for
large and medium surface water systems
and were adjusted for small surface
water systems to account for differences
in source water DBP precursor levels
and operational constraints in small
systems. EPA used ICR data and a
Delphi poll process (a group of drinking
water experts who provided best
professional judgment in a structured
format) to project technologies selected
by ground water systems.
To address uncertainty in SWAT
predictions, EPA also predicted
treatment changes using a second
methodology, called the ‘‘ICR Matrix
Method.’’ Rather than a SWAT-
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predicted pre-Stage 1 baseline, the ICR
Matrix Method uses unadjusted ICR
TTHM and HAA5 pre-Stage 1 data to
estimate the percent of plants changing
technology to comply with the Stage 2
DBPR. EPA gives equal weight to SWAT
and ICR Matrix Method predictions in
estimating Stage 2 compliance forecasts
and resultant reductions in DBP
exposure. The ICR Matrix Method is
also used to estimate reductions in the
occurrence of peak TTHM and HAA5
concentrations because SWATpredicted TTHM and HAA5
concentrations are valid only when
considering national averages, not at the
plant level.
When evaluating compliance with a
DBP MCL, EPA assumed that systems
would maintain DBP levels at least 20
percent below the MCL. This safety
margin represents the level at which
systems typically take action to ensure
they meet a drinking water standard and
reflects industry practice. In addition,
the safety margin accounts for year-toyear fluctuations in DBP levels. To
address the impact of the IDSE, EPA
also analyzed compliance using a safety
margin of 25 percent based on an
analysis of spatial variability in TTHM
and HAA5 occurrence. EPA assigned
equal probability to the 20 and 25
percent safety margin for large and
medium surface water systems for the
final analysis because both alternatives
are considered equally plausible. EPA
assumes the 20 percent operational
safety margin accounts for variability in
small surface water systems and all
groundwater systems.
2. Estimating Benefits
Quantified benefits estimates for the
Stage 2 DBPR are based on potential
reductions in fatal and non-fatal bladder
cancer cases. In the EA, EPA included
a sensitivity analysis for benefits from
avoiding colon and rectal cancers. EPA
believes additional benefits from this
rule could come from reducing potential
reproductive and developmental risks.
EPA has not included these potential
risks in the primary benefit analysis
because of the associated uncertainty.
The major steps in deriving and
characterizing potential cancer cases
avoided include the following: (1)
estimate the current and future annual
cases of illness from all causes; (2)
estimate how many cases can be
attributed to DBP occurrence and
exposure; and (3) estimate the reduction
in future cases corresponding to
anticipated reductions in DBP
occurrence and exposure due to the
Stage 2 DBPR.
EPA used results from the National
Cancer Institute’s Surveillance,
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Epidemiology, and End Results program
in conjunction with data from the 2000
U.S. Census to estimate the number of
new bladder cancer cases per year
(USEPA 2005a). Three approaches were
then used to gauge the percentage of
cases attributable to DBP exposure (i.e.,
population attributable risk (PAR)).
Taken together, the three approaches
provide a reasonable estimate of the
range of potential risks. EPA notes that
the existing epidemiological evidence
has not conclusively established
causality between DBP exposure and
any health risk endpoints, so the lower
bound of potential risks may be as low
as zero.
The first approach used the range of
PAR values derived from consideration
of five individual epidemiology studies.
This range was used at the basis for the
Stage 1 and the proposed Stage 2
economic analyses (i.e., 2 percent to 17
percent) (USEPA 2003a).
The second approach used results
from the Villanueva et al. (2003) metaanalysis. This study develops a
combined Odds Ratio (OR) of 1.2 that
reflects the ever-exposed category for
both sexes from all studies considered
in the meta-analysis and yields a PAR
value of approximately 16 percent.
The third approach used the
Villanueva et al. (2004) pooled data
analysis to develop a dose-response
relationship for OR as a function of
average TTHM exposure. Using the
results from this approach, EPA
estimates a PAR value of approximately
17 percent.
EPA used the PAR values from all
three approaches to estimate the number
of bladder cancer cases ultimately
avoided annually as a result of the Stage
2 DBPR. To quantify the reduction in
cases, EPA assumed a linear
relationship between average DBP
concentration and relative risk of
bladder cancer. Because of this, EPA
considers these estimates to be an upper
bound on the annual reduction in
bladder cancer cases due to the rule.
A lag period (i.e., cessation lag) exists
between when reduction in exposure to
a carcinogen occurs and when the full
risk reduction benefit of that exposure
reduction is realized by exposed
individuals. No data are available that
address the rate of achieving bladder
cancer benefits resulting from DBP
reductions. Consequently, EPA used
data from epidemiological studies that
address exposure reduction to cigarette
smoke and arsenic to generate three
possible cessation lag functions for
bladder cancer and DBPs. The cessation
lag functions are used in conjunction
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with the rule implementation schedule
to project the number of bladder cancer
cases avoided each year as a result of
the Stage 2 DBPR.
Although EPA used three approaches
for estimating PAR, for simplicity’s
sake, EPA used the Villanueva et al.
(2003) study to calculate the annual
benefits of the Stage 2 DBPR. The
benefits estimates derived from
Villanueva et al. (2003) capture a
substantial portion of the overall range
of results, reflecting the uncertainty in
both the underlying OR and PAR values,
as well as the uncertainty in DBP
reductions for Stage 2.
To assign a monetary value to avoided
bladder cancer cases, EPA used the
value of a statistical life (VSL) for fatal
cases and used two alternate estimates
of willingness-to-pay to avoid non-fatal
cases (one based on curable lymphoma
and the other based on chronic
bronchitis). EPA believes additional
benefits from this rule could come from
a reduction in potential reproductive
and developmental risks. See Chapter 6
of the EA for more information on
estimating benefits (USEPA 2005a).
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3. Estimating Costs
Analyzing costs for systems to comply
with the Stage 2 DBPR included
identifying and costing treatment
process improvements that systems will
make, as well as estimating the costs to
implement the rule, conduct IDSEs,
prepare monitoring plans, perform
additional routine monitoring, and
evaluate significant DBP excursion
events. The cost analysis for States/
Primacy Agencies included estimates of
the labor burdens for training employees
on the requirements of the Stage 2
DBPR, responding to PWS reports, and
record keeping.
All treatment costs are based on mean
unit cost estimates for advanced
technologies and chloramines.
Derivation of unit costs are described in
detail in Technologies and Costs for the
Final Long Term 2 Enhanced Surface
Water Treatment Rule and Final Stage 2
Disinfectants and Disinfection
Byproducts Rule (USEPA 2005g). Unit
costs (capital and O&M) for each of nine
system size categories are calculated
using mean design and average daily
flows values. The unit costs are then
combined with the predicted number of
plants selecting each technology to
produce national treatment cost
estimates.
Non-treatment costs for
implementation, the IDSE, monitoring
plans, additional routine monitoring,
and operational evaluations are based
on estimates of labor hours for
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performing these activities and on
laboratory costs.
While systems vary with respect to
many of the input parameters to the
Stage 2 DBPR cost analysis (e.g., plants
per system, population served, flow per
population, labor rates), EPA believes
that mean values for the various input
parameters are appropriate to generate
the best estimate of national costs for
the rule. Uncertainty in the national
average unit capital and O&M costs for
the various technologies has been
incorporated into the cost analysis
(using Monte Carlo simulation
procedures). Costs of the Stage 2 DBPR
are estimated at both mean and 90
percent confidence bound values.
EPA assumes that systems will, to the
extent possible, pass cost increases on to
their customers through increases in
water rates. Consequently, EPA has also
estimated annual household cost
increases for the Stage 2 DBPR. This
analysis includes costs for all
households served by systems subject to
the rule, costs just for those households
served by systems actually changing
treatment technologies to comply with
the rule, costs for households served by
small systems, and costs for systems
served by surface water and ground
water sources.
4. Comparing Regulatory Alternatives
Through the analyses summarized in
this section, EPA assessed the benefits
and costs of the four regulatory
alternatives described previously.
Succeeding sections of this preamble
present the results of these analyses. As
recommended by the Advisory
Committee, EPA is establishing the
preferred regulatory alternative for
today’s Stage 2 DBPR. This regulation
will reduce peak DBP concentrations in
distribution systems through requiring
compliance determinations with
existing TTHM and HAA5 MCLs using
the LRAA. Further, the IDSE will ensure
that systems identify compliance
monitoring sites that reflect high DBP
levels. EPA believes that these provision
are appropriate given the association of
DBPs with cancer, as well as potential
reproductive and developmental health
effects.
Alternative 1 would have established
the same DBP regulations as the
preferred alternative, and would have
lowered the bromate MCL from 0.010 to
0.005 mg/L. The Advisory Committee
did not recommend and EPA did not
establish this alternative because it
could have an adverse effect on
microbial protection. The lower bromate
MCL could cause many systems to
reduce or eliminate the use of ozone,
which is an effective disinfectant for a
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445
broad spectrum of microbial pathogens,
including microorganisms like
Cryptosporidium that are resistant to
chlorine.
Alternative 2 would have prohibited
any single sample from exceeding the
TTHM or HAA5 MCL. This is
significantly more stringent than the
preferred alternative and would likely
require a large fraction of surface water
systems to switch from their current
treatment practices to more expensive
advanced technologies. Consistent with
the Advisory Committee, EPA does not
believe such a drastic shift is warranted
at this time.
Similarly, Alternative 3, which would
decrease TTHM and HAA5 MCLs to
0.040 mg/L and 0.030 mg/L,
respectively, and would require a
significant portion of surface water
systems to implement expensive
advanced technologies in place of their
existing treatment. Further, compliance
with TTHM and HAA5 MCLs under this
alternative would be based on the RAA,
which does not specifically address DBP
peaks in the distribution system as the
LRAA, in conjunction with the IDSE,
are designed to do. Based on these
considerations, EPA and the Advisory
Committee did not favor this alternative.
C. Benefits of the Stage 2 DBPR
The benefits analysis for the Stage 2
DBPR includes a description of nonquantified benefits, calculations of
quantified benefits, and a discussion of
when benefits will occur after today’s
final rule is implemented. An overview
of the methods used to determine
benefits is provided in Section VI.B.
More detail can be found in the final
EA. A summary of benefits for the Stage
2 DBPR is given in this section.
1. Nonquantified Benefits
Non-quantified benefits of the Stage 2
DBPR include potential benefits from
reduced reproductive and
developmental risks, reduced risks of
cancers other than bladder cancer, and
improved water quality. EPA believes
that additional benefits from this rule
could come from a reduction in
potential reproductive and
developmental risks. However, EPA
does not believe the available evidence
provides an adequate basis for
quantifying these potential risks in the
primary analysis.
Both toxicology and epidemiology
studies indicate that other cancers may
be associated with DBP exposure but
currently there is not enough data to
include them in the primary analysis.
However, EPA believes that the
association between exposure to DBPs
and colon and rectal cancer is possibly
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significant, so an analysis of benefits is
presented as a sensitivity analysis.
To the extent that the Stage 2 DBPR
changes perceptions of the health risks
associated with drinking water and
improves taste and odor, it may reduce
actions such as buying bottled water or
installing filtration devices. Any
resulting cost savings would be a
regulatory benefit. Also, as PWSs move
away from conventional treatment to
more advanced technologies, other nonhealth benefits are anticipated besides
better tasting and smelling water. For
example, GAC lowers nutrient
availability for bacterial growth,
produces a biologically more stable
finished water, and facilitates
management of water quality in the
distribution system. Since GAC also
removes synthetic organic chemicals
(SOCs), it provides additional protection
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from exposure to chemicals associated
with accidental spills or environmental
runoff.
2. Quantified Benefits
EPA has quantified the benefits
associated with the expected reductions
in the incidence of bladder cancer. As
discussed in Section VI.B, EPA used the
PAR values from all three approaches to
estimate the number of bladder cancer
cases ultimately avoided annually as a
result of the Stage 2 DBPR, shown in
Figure VI.C–1.
Table VI.C–1 summarizes the
estimated number of bladder cancer
cases avoided as a result of the Stage 2
DBPR, accounting for cessation lag and
the rule implementation schedule, and
the monetized value of those cases. The
benefits in Table VI.C–1 were developed
using the PAR value from Villanueva et
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al. (2003), as described in Section VI.B.
Table VI.C–1 summarizes the benefits
for the Preferred Regulatory Alternative
for the Stage 2 DBPR. Benefits estimates
for the other regulatory alternatives
were derived using the same methods as
for the Preferred Regulatory Alternative
and are presented in the EA.
The confidence bounds of the results
in Table VI.C–1 reflect uncertainty in
PAR, uncertainty in the compliance
forecast and resulting reduction in DBP
concentrations, and cessation lag.
Confidence bounds of the monetized
benefits also reflect uncertainty in
valuation parameters. An estimated 26
percent of bladder cancer cases avoided
are fatal, and 74 percent are non-fatal
(USEPA 1999b). The monetized benefits
therefore reflect the estimate of avoiding
both fatal and non-fatal cancers in those
proportions.
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TABLE VI.C–1.—SUMMARY OF QUANTIFIED BENEFITS FOR THE STAGE 2 DBPR (MILLIONS OF $2003)
Annual average cases avoided
Mean
5th
95th
279
103
541
188
61
399
333
138
610
Discount rate, WTP for nonfatal cases
3%, Lymphoma ...................
7% Lymphoma ....................
3% Bronchitis ......................
7% Bronchitis ......................
3%, Lymphoma ...................
7% Lymphoma ....................
3% Bronchitis ......................
7% Bronchitis ......................
3%, Lymphoma ...................
7% Lymphoma ....................
3% Bronchitis ......................
7% Bronchitis ......................
Annualized benefits of cases avoided
Cessation lag model
Mean
5th
$1,531
1,246
763
621
1,032
845
514
420
1,852
1,545
922
769
95th
$233
190
165
135
157
129
111
91
282
235
200
167
$3,536
2,878
1,692
1,376
2,384
1,950
1,141
932
4,276
3,566
2,045
1,704
Smoking/Lung Cancer
Smoking/Bladder Cancer
Arsenic/Bladder Cancer
Notes: Values are discounted and annualized in 2003$. The 90 percent confidence interval for cases incorporates uncertainty in PAR, reduction in average TTHM and HAA5 concentrations, and cessation lag. The 90 percent confidence bounds for monetized benefits reflect uncertainty
in monetization inputs relative to mean cases. Based on TTHM as an indicator, benefits were calculated using the Villanueva et al. (2003) PAR.
EPA recognizes that benefits may be as low as zero since causality has not yet been established between exposure to chlorinated water and
bladder cancer. Assumes 26 percent of cases are fatal, 74 percent are non-fatal (USEPA 1999b).
Source: Exhibit 6.1, USEPA 2005a.
3. Timing of Benefits Accrual
years after the exposure reduction has
occurred, the annual cases avoided will
be 489 for the smoking/lung cancer
cessation lag model, 329 for the
smoking/bladder cancer cessation lag
model, and 534 cases for the arsenic/
bladder cancer cessation lag model.
These represent approximately 84%,
57%, and 92%, respectively, of the
estimated 581 annual cases ultimately
avoidable by the Stage 2 DBPR.
In addition to the delay in reaching a
steady-state level of risk reduction as a
result of cessation lag, there is a delay
in attaining maximum exposure
reduction across the entire affected
population that results from the Stage 2
DBPR implementation schedule. For
example, large surface water PWSs have
six years from rule promulgation to
meet the new Stage 2 MCLs, with up to
a two-year extension possible for capital
improvements. In general, EPA assumes
that a fairly constant increment of
systems will complete installation of
new treatment technologies each year,
with the last systems installing
treatment by 2016. The delay in
exposure reduction resulting from the
rule implementation schedule is
incorporated into the benefits model by
adjusting the cases avoided for the given
year and is illustrated in Table VI.C–2.
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EPA recognizes that it is unlikely that
all cancer reduction benefits would be
realized immediately upon exposure
reduction. Rather, it is expected that
there will likely be some transition
period as individual risks reflective of
higher past exposures at the time of rule
implementation become, over time,
more reflective of the new lower
exposures. EPA developed cessation lag
models for DBPs from literature to
describe the delayed benefits, in
keeping with the recommendations of
the SAB (USEPA 2001d). Figure VI.C–2
illustrates the effects of the cessation lag
models. The results from the cessation
lag models show that the majority of the
potential cases avoided occur within the
first fifteen years after initial reduced
exposure to DBPs. For example, fifteen
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TABLE VI.C–2.—BLADDER CANCER CASES AVOIDED (TTHM AS INDICATOR) EACH YEAR USING THREE CESSATION LAG
MODELS
Smoking/lung cancer
cessation lag model
Year
Total
1 ...............................................................................................................
2 ...............................................................................................................
3 ...............................................................................................................
4 ...............................................................................................................
5 ...............................................................................................................
6 ...............................................................................................................
7 ...............................................................................................................
8 ...............................................................................................................
9 ...............................................................................................................
10 .............................................................................................................
11 .............................................................................................................
12 .............................................................................................................
13 .............................................................................................................
14 .............................................................................................................
15 .............................................................................................................
16 .............................................................................................................
17 .............................................................................................................
18 .............................................................................................................
19 .............................................................................................................
20 .............................................................................................................
21 .............................................................................................................
22 .............................................................................................................
23 .............................................................................................................
24 .............................................................................................................
25 .............................................................................................................
Percent
0
0
0
0
0
24
62
111
170
220
265
305
341
371
396
416
433
448
460
471
481
489
496
503
509
Smoking/bladder cancer cessation lag
model
Total
0
0
0
0
0
4
11
19
29
38
46
53
59
64
68
72
75
77
79
81
83
84
86
87
88
Percent
0
0
0
0
0
23
54
90
132
161
184
204
221
237
251
265
278
289
301
311
321
330
339
347
355
0
0
0
0
0
4
9
16
23
28
32
35
38
41
43
46
48
50
52
54
55
57
59
60
61
Arsenic/bladder cancer cessation lag
model
Total
0
0
0
0
0
45
110
187
275
334
379
412
438
458
475
488
499
509
516
523
528
533
537
541
544
Percent
0
0
0
0
0
8
19
32
48
58
65
71
76
79
82
84
86
88
89
90
91
92
93
93
94
Notes: Percent of annual cases ultimately avoidable achieved during each of the first 25 years. The benefits model estimates 581 (90% CB =
229–1,079) annual cases ultimately avoidable using the Villanueva et al. (2003) PAR inputs and including uncertainty in these and DBP reductions. EPA recognizes that benefits may be as low as zero since causality has not yet been established between exposure to chlorinated water
and bladder cancer.
Source: Summarized from detailed results presented in Exhibits E.38a, E.38e and E.38i, USEPA 2005a.
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D. Costs of the Stage 2 DBPR
National costs include those of
treatment changes to comply with the
rule as well as non-treatment costs such
as for Initial Distribution System
Evaluations (IDSEs), additional routine
monitoring, and operational
evaluations. The methodology used to
estimate costs is described in Section
VI.B. More detail is provided in the EA
(USEPA 2005a). The remainder of this
section presents summarized results of
EPA’s cost analysis for total annualized
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present value costs, PWS costs, State/
Primacy agency costs, and nonquantified costs.
1. Total Annualized Present Value Costs
Tables VI.D–1 and VI.D–2 summarize
the average annualized costs for the
Stage 2 DBPR Preferred Regulatory
Alternative at 3 and 7 percent discount
rates, respectively. System costs range
from approximately $55 to $101 million
annually at a 3 percent discount rate,
with a mean estimate of approximately
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$77 million per year. The mean and
range of annualized costs are similar at
a 7 percent discount rate. State costs are
estimated to be between $1.70 and $1.71
million per year depending on the
discount rate. These estimates are
annualized starting with the year of
promulgation. Actual dollar costs
during years when most treatment
changes are expected to occur would be
somewhat higher (the same is true for
benefits that occur in the future).
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2. PWS costs
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PWS costs for the Stage 2 DBPR
include non-treatment costs of rule
implementation, Initial Distribution
System Evaluations (IDSEs), Stage 2
DBPR monitoring plans, additional
routine monitoring, and operational
evaluations. Systems required to install
treatment to comply with the MCLs will
accrue the additional costs of treatment
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installation as well as operation and
maintenance. Significant PWS costs for
IDSEs, treatment, and monitoring are
described in this section, along with a
sensitivity analysis.
a. IDSE costs. Costs and burden
associated with IDSE activities differ
depending on whether or not the system
performs the IDSE and, if so, which
option a system chooses. All systems
performing the IDSE are expected to
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incur some costs. EPA’s analysis
allocated systems into five categories to
determine the costs of the IDSE—those
conducting standard monitoring, SSS,
VSS, 40/30, and NTNCWS not required
to do an IDSE. EPA then developed cost
estimates for each option. Tables VI.D–
3, VI.D–4, and VI.D–5 illustrate PWS
costs for IDSE for systems conducting an
SMP, SSS, and 40/30, respectively.
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b. PWS treatment costs. The number
of plants changing treatment as a result
of the Stage 2 DBPR and which
technology various systems will install
are determined from the compliance
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forecast. The percent of systems
predicted to make treatment technology
changes and the technologies predicted
to be in place after implementation of
the Stage 2 DBPR are shown in Table
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VI.D–6. The cost model includes
estimates for the cost of each
technology; the results of the cost model
for PWS treatment costs are summarized
in Table VI.D–7.
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c. Monitoring costs. Because systems
already sample for the Stage 1 DBPR,
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costs for additional routine monitoring
are determined by the change in the
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number of samples to be collected from
the Stage 1 to the Stage 2 DBPR. The
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number of treatment plants. With this
modification in monitoring scheme, the
average system will have no change in
monitoring costs. The number of
samples required is estimated to
increase for some systems but actually
decrease from the Stage 1 to the Stage
2 DBPR for many systems. Table VI.D–
8 summarizes the estimated additional
routine monitoring costs for systems.
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Stage 2 DBPR monitoring requirements
for systems are based only on
population served and source water
type, while the Stage 1 DBPR
requirements are also based on the
457
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3. State/Primacy Agency Costs
To estimate State/Primacy Agency
costs, the estimated number of full-time
equivalents (FTEs) required per activity
4. Non-quantified Costs
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All significant costs that EPA has
identified have been quantified. In some
instances, EPA did not include a
potential cost element because its effects
are relatively minor and difficult to
estimate. For example, it may be less
costly for a small system to merge with
neighboring systems than to add
advanced treatment. Such changes have
both costs (legal fees and connecting
infrastructure) and benefits (economies
of scale). Likewise, procuring a new
source of water would have costs for
new infrastructure, but could result in
lower treatment costs. Operational costs
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is multiplied by the number of labor
hours per FTE, the State/Primacy
Agency hourly wage, and the number of
States/Primacy Agencies. EPA estimated
the number of FTEs required per
activity based on experience
implementing previous rules, such as
the Stage 1 DBPR. State/Primacy Agency
costs are summarized in Table VI.D–9.
such as changing storage tank operation
were also not considered as alternatives
to treatment. These might be options for
systems with a single problem area with
a long residence time. In the absence of
detailed information needed to evaluate
situations such as these, EPA has
included a discussion of possible effects
where appropriate. In general, however,
the expected net effect of such
situations is lower costs to PWSs. Thus,
the EA tends to present conservatively
high estimates of costs in relation to
non-quantified costs.
E. Household Costs of the Stage 2 DBPR
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EPA estimates that, as a whole,
households subject to the Stage 2 DBPR
face minimal increases in their annual
costs. Approximately 86 percent of the
households potentially subject to the
rule are served by systems serving at
least 10,000 people; these systems
experience the lowest increases in costs
due to significant economies of scale.
Households served by small systems
that add treatment will face the greatest
increases in annual costs. Table VI.E–1
summarizes annual household cost
increases for all system sizes.
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TABLE VI.E–1.—ANNUAL HOUSEHOLD COST INCREASES.
Mean annual household cost increase
Total number
of households
served
90th percentile annual household cost increase
Median annual household cost increase
95th percentile annual household cost increase
Percentage
of annual
household
cost increase <
$12 (percent)
Percentage
of annual
household
cost increase <
$120 (percent)
$0.98
2.57
7.24
1.81
0.99
0.08
99
97
95
99
98
100
100
100
99
100
100
100
$22.40
197.62
177.93
11.31
197.62
33.84
92
38
47
96
31
79
99
89
85
100
92
100
Households Served by All Plants
All Systems ..........................................
All Small Systems ................................
SW < 10,000 ........................................
SW ≥ 10,000 ........................................
GW < 10,000 .......................................
GW ≥ 10,000 ........................................
101,553,868
14,261,241
3,251,893
62,137,350
11,009,348
25,155,277
$0.62
2.20
4.58
0.46
1.49
0.13
$0.03
0.10
0.79
0.02
0.02
0.00
$0.36
0.79
2.69
0.35
0.39
0.03
Households Served by Plants Adding Treatment
All Systems ..........................................
All Small Systems ................................
SW < 10,000 ........................................
SW ≥ 10,000 ........................................
GW < 10,000 .......................................
GW ≥ 10,000 ........................................
10,161,304
591,623
285,911
9,060,119
305,712
509,562
$5.53
46.48
43.05
2.83
49.69
5.97
$0.80
18.47
13.79
0.80
16.65
1.37
$10.04
168.85
173.53
6.98
109.86
26.82
Notes: Detail may not add to total due to independent rounding. Number of households served by systems adding treatment will be higher
than households served by plants adding treatment because an entire system will incur costs even if only some of the plants for that system add
treatment (this would result in lower household costs, however).
Source: Exhibit 7.15, USEPA 2005a.
F. Incremental Costs and Benefits of the
Stage 2 DBPR
Incremental costs and benefits are
those that are incurred or realized in
reducing DBP exposures from one
alternative to the next more stringent
alternative. Estimates of incremental
costs and benefits are useful in
considering the economic efficiency of
different regulatory options considered
by the Agency. Generally, the goal of an
incremental analysis is to identify the
regulatory option where net social
benefits are maximized. However, the
usefulness of this analysis is
constrained when major benefits and/or
costs are not quantified or not
monetized. Also, as pointed out by the
Environmental Economics Advisory
Committee of the Science Advisory
Board, efficiency is not the only
appropriate criterion for social decision
making (USEPA 2000i).
For the proposed Stage 2 DBPR,
presentation of incremental quantitative
benefit and cost comparisons may be
unrepresentative of the true net benefits
of the rule because a significant portion
of the rule’s potential benefits are not
quantified, particularly potential
reproductive and developmental health
effects (see Section VI.C). Table VI.F–1
shows the incremental monetized costs
and benefits for each regulatory
alternative. Evaluation of this table
shows that incremental costs generally
fall within the range of incremental
benefits for each more stringent
alternative. Equally important, the
addition of any benefits attributable to
the non-quantified categories would add
to the benefits without any increase in
costs.
Table VI.F–1 shows that the Preferred
Alternative is the least-cost alternative.
A comparison of Alternative 1 with the
Preferred Alternative shows that
Alternative 1 would have approximately
the same benefits as the Preferred
Alternative. The costs of Alternative 1
are greater due to the additional control
of bromate. However, the benefits of
Alternative 1 are less than the Preferred
Alternative because the Agency is not
able to estimate the additional benefits
of reducing the bromate MCL.
Alternative 1 was determined to be
unacceptable due to the potential for
increased risk of microbial exposure.
Both benefits and costs are greater for
Alternative 2 and Alternative 3 as
compared to the Preferred Alternative.
However, these regulatory alternatives
do not have the risk-targeted design of
the Preferred Alternative. Rather,
implementation of these stringent
standards would require a large number
of systems to change treatment
technology. The high costs of these
regulatory alternatives and the drastic
shift in the nation’s drinking water
practices were considered unwarranted
at this time. (See Section VI.A of this
preamble for a description of regulatory
alternatives.)
TABLE VI.F–1.—INCREMENTAL COSTS AND BENEFITS OF THE STAGE 2 DBPR
Annual
costs
Rule alternative
Annual benefits
Incremental costs
Incremental benefits
Incremental net benefits
A
WTP for non-fatal
bladder cancer cases
B
C
D
E=D¥C
$79 ..........................
(1) ............................
343 ..........................
212 ..........................
79 ............................
$1,531 .....................
(1) ............................
3,637 .......................
1,962 .......................
763 ..........................
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3 Percent Discount Rate
Lymphoma ...............
Bronchitis .................
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Preferred .................
Alternative 1 1 ..........
Alternative 2 ............
Alternative 3 ............
Preferred .................
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$79
254
422
634
79
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$1,531
1,377
5,167
7,130
763
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$1,452
(1)
3,294
1,750
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TABLE VI.F–1.—INCREMENTAL COSTS AND BENEFITS OF THE STAGE 2 DBPR—Continued
Annual
costs
Rule alternative
Annual benefits
Incremental costs
Incremental benefits
Incremental net benefits
A
WTP for non-fatal
bladder cancer cases
B
C
D
E=D¥C
(1) ............................
343 ..........................
212 ..........................
(1) ............................
1,812 .......................
978 ..........................
(1)
1,469
765
$1,246 .....................
(1) ............................
2,981 .......................
1,605 .......................
621 ..........................
(1) ............................
1,484 .......................
799 ..........................
$1,170
(1)
2,651
1,399
544
(1)
1,154
593
Alternative 1 1 ..........
Alternative 2 ............
Alternative 3 ............
254
422
634
686
2,575
3,552
7 Percent Discount Rate
Lymphoma ...............
Bronchitis .................
Preferred .................
Alternative 1 1 ..........
Alternative 2 ............
Alternative 3 ............
Preferred .................
Alternative 1 1 ..........
Alternative 2 ............
Alternative 3 ............
$77
242
406
613
77
242
406
613
$1,246
1,126
4,227
5,832
621
561
2,105
2,904
$77 ..........................
(1) ............................
330 ..........................
207 ..........................
77 ............................
(1) ............................
330 ..........................
207 ..........................
Notes: Estimates are discounted to 2003 and given in 2003 dollars. Based on TTHM as an indicator, Villanueva et al. (2003) for baseline risk,
and smoking/lung cancer cessation lag model. Assumes 26 percent of cases are fatal, 74 percent are non-fatal (USEPA 1999b). EPA recognizes
that benefits may be as low as zero since causality has not yet been established between exposure to chlorinated water and bladder cancer.
1 Alternative 1 appears to have fewer benefits than the Preferred Alternative because it does not incorporate the IDSE, as explained in Chapter
4. Furthermore, this EA does not quantify the benefits of reducing the MCL for bromate (and potentially associated cancer cases), a requirement
that is included only in Alternative 1. This means that Alternative 1 is dominated by the Preferred Alternative in this analysis (having higher costs
than the Preferred Alternative but lower benefits), and so it is not included in the incremental comparison of alternatives (Columns C–E). OMB
states this in terms of comparing cost effectiveness ratios, but the same rule applies to an incremental cost, benefits, or net benefits comparison:
‘‘When constructing and comparing incremental cost-effectiveness ratios, [analysts] * * * should make sure that inferior alternatives identified by
the principles of strong and weak dominance are eliminated from consideration.’’ (OMB Circular A–4, p. 10)
Source: Exhibit 9.13, USEPA 2005a.
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G. Benefits From the Reduction of Cooccurring Contaminants
Installing certain advanced
technologies to control DBPs has the
added benefit of controlling other
drinking water contaminants in addition
to those specifically targeted by the
Stage 2 DBPR. For example, membrane
technology installed to reduce DBP
precursors can also reduce or eliminate
many other drinking water
contaminants (depending on pore size),
including those that EPA may regulate
in the future. Removal of any
contaminants that may face regulation
could result in future cost savings to a
water system. Because of the difficulties
in establishing which systems would be
affected by other current or future rules,
no estimate was made of the potential
cost savings from addressing more than
one contaminant simultaneously.
H. Potential Risks From Other
Contaminants
Along with the reduction in DBPs
from chlorination such as TTHM and
HAA5 as a resultof the Stage 2 DBPR,
there may be increases in other DBPs as
systems switch from chlorine to
alternative disinfectants. For all
disinfectants, many DBPs are not
regulated and many others have not yet
been identified. EPA will continue to
review new studies on DBPs and their
occurrence levels to determine if they
pose possible health risks. EPA
continues to support regulation of
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TTHM and HAA5 as indicators for
chlorination DBP occurrence and
believes that operational and treatment
changes made because of the Stage 2
DBPR will result in an overall decrease
in risk.
1. Emerging DBPs
Iodo-DBPs and nitrogenous DBPs
including halonitromethanes are DBPs
that have recently been reported
(Richardson et al. 2002, Richardson
2003). One recent occurrence study
sampled quarterly at twelve surface
water plants using different
disinfectants across the U.S. for several
iodo-THMs and halonitromethane
species (Weinberg et al. 2002). The
concentrations of iodo-THMs and
halonitromethane in the majority of
samples in this study were less than the
analytical minimum reporting levels;
plant-average concentrations of iodoTHM and halonitromethane species
were typically less than 0.002 mg/L,
which is an order of magnitude lower
than the corresponding average
concentrations of TTHM and HAA5 at
those same plants. Chloropicrin, a
halonitromethane species, was also
measured in the ICR with a median
concentration of 0.00019 mg/L across all
surface water samples. No occurrence
data exist for the iodoacids due to the
lack of a quantitative method and
standards. Further work on chemical
formation of iodo-DBPs and
halonitromethanes is needed.
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Iodoacetic acid was found to be
cytotoxic and genotoxic in Salmonella
and mammalian cells (Plewa et al.
2004a) as were some of the
halonitromethanes (Kundu et al. 2004;
Plewa et al. 2004b). Although potent in
these in vitro screening studies, further
research is needed to determine if these
DBPs are active in living systems. No
conclusions on human health risk can
be drawn from such preliminary
studies.
2. N-Nitrosamines
Another group of nitrogenous DBPs
are the N-nitrosamines. A number of Nnitrosamines exist, and Nnitrosodimethylamine (NDMA), a
probable human carcinogen (USEPA
1993), has been identified as a potential
health risk in drinking water. NDMA is
a contaminant from industrial sources
and a potential disinfection byproduct
from reactions of chlorine or chloramine
with nitrogen containing organic matter
and from some polymers used as
coagulant aids. Studies have produced
new information on the mechanism of
formation of NDMA, but there is not
enough information at this time to draw
conclusions regarding a potential
increase in NDMA occurrence as
systems change treatment. Although
there are studies that examined the
occurrence of NDMA in some water
systems, there are no systematic
evaluations of the occurrence of NDMA
and other nitrosamines in U.S. waters.
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Recent studies have provided new
occurrence information that shows
NDMA forms in both chlorinated and
chloraminated systems. Barrett et al.
(2003) reported median concentrations
of less than 2ng/L for the seven chlorine
systems studied and less than 3 ng/L for
13 chloramine systems. Another study
demonstrated that factors other than
disinfectant type may play an important
role in the formation of NDMA
(Schreiber and Mitch 2005). More
research is underway to determine the
extent of NDMA occurrence in drinking
water systems. EPA has proposed
monitoring for NDMA under
Unregulated Contaminant Monitoring
Rule 2 (70 FR 49094, at 49103, August
22, 2005) (USEPA 2005m).
Risk assessments have estimated that
the 10¥6 lifetime cancer risk level is 7
ng/L based on induction of tumors at
multiple sites. NDMA is also present in
food, tobacco smoke, and industrial
emissions, and additional research is
underway to determine the relative
exposure of NDMA in drinking water to
these other sources.
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3. Other DBPs
Some systems, depending on bromide
and organic precursor levels in the
source water and technology selection,
may experience a shift to higher ratios,
or concentrations, of brominated DBPs
while the overall TTHM or HAA5
concentration may decrease. In some
instances where alternative
disinfectants are used, levels of chlorite
and bromate may increase as a result of
systems switching to chlorine dioxide or
ozone, respectively. However, EPA
anticipates that changes in chlorite and
bromate concentration as a result of the
Stage 2 DBPR will be minimal (USEPA
2005a). For most systems, overall levels
of DBPs, as well as brominated DBP
species, should decrease as a result of
this rule. EPA continues to believe that
precursor removal is a highly effective
strategy to reduce levels of DBPs.
EPA also considered the impact this
rule may have on microbial
contamination that may result from
altering disinfection practices. To
address this concern, the Agency
developed this rule jointly with the
Long Term 2 Enhanced Surface Water
Treatment Rule (LT2ESWTR). EPA
expects that the LT2ESWTR provisions
will prevent increases in microbial risk
resulting from the Stage 2 DBPR.
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I. Effects of the Contaminant on the
General Population and Groups Within
the General Population That Are
Identified As Likely To Be at Greater
Risk of Adverse Health Effects
EPA’s Office of Water has historically
considered risks to sensitive
subpopulations (including fetuses,
infants, and children) when establishing
drinking water assessments, advisories
and other guidance, and standards
(USEPA 1989) (56 FR 3526, January 30,
1991) (USEPA 1991). In the case of
Stage 2 DBPR, maximizing health
protection for sensitive subpopulations
requires balancing risks to achieve the
recognized benefits of controlling
waterborne pathogens while minimizing
risk of potential DBP toxicity.
Experience shows that waterborne
disease from pathogens in drinking
water is a major concern for children
and other subgroups (e.g., the elderly,
immunocompromised, and pregnant
women) because of their greater
vulnerabilities (Gerba et al. 1996). EPA
believes DBPs may also potentially pose
risks to fetuses and pregnant women
(USEPA 1998a). In addition, because the
elderly population (age 65 and above) is
naturally at a higher risk of developing
bladder cancer, their health risks may
further increase as a result of long-term
DBP exposure (National Cancer Institute
2002).
In developing this rule, risks to
sensitive subpopulations, including
children, were taken into account in the
assessments of disinfectants and DBPs.
More details on sensitive
subpopulations can be found in the
Economic Analysis (USEPA 2005a). For
each of the DBPs included in the Stage
2 DBPR, the maximum contaminant
level goals (MCLG) are derived using the
most sensitive endpoint among all
available data and an intraspecies
uncertainty factor of 10 which accounts
for human variability including
sensitive subpopulations, like children.
The Agency has evaluated several
alternative regulatory options and
selected the one that balances cost with
significant benefits, including those for
sensitive subpopulations. The Stage 2
DBPR will result in a potential
reduction in cancer risk and a potential
reduction in reproductive and
developmental risk to fetuses and
pregnant women. It should be noted that
the LT2ESWTR, which accompanies
this rule, reduces pathogens in drinking
water and further protects sensitive
subpopulations. See Section VII.G for a
discussion of EPA’s requirements under
Executive Order 13045.
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J. Uncertainties in the Risk, Benefit, and
Cost Estimates for the Stage 2 DBPR
For today’s final rule, EPA has
estimated the current baseline risk from
exposure to DBPs in drinking water and
projected the risk reduction and cost for
various rule alternatives. There is
uncertainty in the risk calculation, the
benefit estimates, the cost estimates, and
the interaction with other regulations.
The EA has an extensive discussion of
relevant uncertainties (USEPA 2005a).
This section briefly summarizes the
major uncertainties. Table VI.J–1
presents a summary of uncertainty in
the cost and benefit estimates, refers to
the section or appendix of the EA where
the information is introduced, and
estimates the potential effects that each
may have on national cost and benefit
estimates.
EPA believes that uncertainty in the
compliance forecast has a potentially
large influence on cost and benefit
estimates for today’s rule. Thus, the
Agency has attempted to quantify the
uncertainty by giving equal weight to
two different compliance forecast
approaches. One compliance forecast
approach is based on the SWAT
predictions, and the other is based on
the ‘‘ICR Matrix Method.’’ The ICR
Matrix Method uses the same basic
approach as SWAT, but uses TTHM and
HAA5 data from the ICR directly to
estimate the percent of plants changing
technology to comply with the Stage 2
DBPR and the resulting DBP reduction.
To characterize the uncertainty of the
compliance forecast results, EPA
assumes a uniform distribution between
SWAT and ICR Matrix Method results
(USEPA 2005a). That is, the cost and
benefit estimates presented in the
preamble represent the midpoint
between costs and benefits estimated
using the SWAT model, and those
estimated using the ICR Matrix Method.
Cost estimates using the SWAT model
are about 25% lower than the midpoint
estimates, while those using the ICR
Matrix Method are about 25% higher.
Benefits estimated using the SWAT
model are about 30% lower than the
midpoint estimates, while those using
the ICR Matrix Method are about 30%
higher.
EPA believes the compliance forecast
may be overstated because the
technology decision tree does not
consider low-cost, non-treatment system
improvements that could be used to
comply with the Stage 2 DBPR. These
improvements, including things like
flushing more frequently and managing
storage facilities to reduce water age,
could be used by systems to reduce
TTHM and HAA5 levels for specific
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locations in their distribution system to
meet Stage 2 DBPR MCLs. Thus, the
standard compliance forecast method as
developed during the M/DBP FACA
(with a 20 percent safety margin) is a
reasonable estimation. However, SWAT
does not explicitly consider the IDSE.
To address uncertainty in the impact of
the IDSE on the compliance forecast,
EPA revised the compliance forecast
methodology, assigning equal
probability to 20 and 25 percent
operational safety margins. EPA believes
the 25 percent safety margin is a
reasonable high-end estimate of system
response to account for the influences of
the IDSE. EPA used a spatial variability
analysis to determine the appropriate
safety margin to use to estimate the
impact of the IDSE on the compliance
forecast.
These alternative approaches for the
compliance forecast estimate are used to
represent a range of possible results and
are incorporated into the cost and
benefit models using Monte Carlo
probability functions. EPA believes this
approach helps inform the reader of the
likely magnitude of the impact of the
uncertainties.
In addition to quantifying some
uncertainties in the compliance
forecasts, EPA has explicitly accounted
for uncertainty in estimated treatment
technology costs. Treatment costs are
modeled using a triangular distribution
of ± 30 percent for Capital, and ± 15
percent for O&M costs to recognize that
the assumptions for cost analysis to
produce the national average are
uncertain.
For the cost estimates, uncertainty
also exists in baseline data inputs, such
as the total number of disinfecting
plants and their typical average and
design flow rates. Other cost model
inputs such as labor rates and laboratory
fees also contain uncertainties. In these
cases, EPA has evaluated available data
and estimated a cost input value to
represent the average of all water
systems nationally. EPA recognizes that
there is uncertainty in this average and
variability in the characteristics of
individual systems. The influence of
these uncertainties on national cost
estimates is expected to be fairly minor.
For the benefits estimates, uncertainty
exists in model inputs such as the
estimated PAR values and the cessation
lag models. EPA considered three
approaches to estimate attributable risk:
(1) a range of risk derived from
individual studies, (2) a risk estimate
from a meta-analysis, and (3) a risk
estimate from a pooled analysis. To
quantify uncertainty in cessation lag,
three independent cessation lag models
derived from three different
epidemiological studies are used. Also,
two functional forms are used for each
of these data sets and uncertainty in the
parameters of those functions is
included in the analysis. As noted
previously, causality has not been
established between DBP levels and
cancer endpoints, so the lower bound of
potential risk reductions may be as low
as zero.
In a number of different contexts over
the past few years, the Agency has
considered the relative merits and
assumptions encountered when
employing meta-analyses. Cessation lag
modeling is a relatively recent analysis
that the Agency has incorporated into
its risk analyses to more appropriately
model the timing of health benefits. The
specific papers upon which the Stage 2
analysis is based have been peer
reviewed. However, the Agency believes
that it is time to consider these Agencywide science issues in a broader sense
with outside experts to better inform the
Agency’s future analyses.
For monetization of benefits, EPA
uses two alternatives for valuing nonfatal bladder cancer. Other
uncertainties, such as the linear
relationship between DBP reductions
and reductions in bladder cancer cases
avoided, are discussed qualitatively.
In addition to the uncertainties
quantified as part of the benefits
evaluation, other uncertainties that have
not been quantified could result in
either an over-or under-estimation of the
benefits. Two of the greatest
uncertainties affecting the benefits of
the Stage 2 DBPR, benefits from
potential reductions of cancers other
than bladder and benefits from possible
reductions in potential reproductive and
developmental health effects, are
unquantified. Both of these factors
could result in an underestimation of
quantified Stage 2 DBPR benefits.
TABLE VI.J–1.—EFFECTS OF UNCERTAINTIES ON NATIONAL ESTIMATES
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Assumptions for which there
is uncertainty
Section with
full discussion
of uncertainty
Uncertainty in the industry
baseline (SDWIS and
1995 CWSS data).
Uncertainty in observed data
and predictive tools used
to characterize DBP occurrence for the pre-Stage
1 baseline.
Uncertainty in predictive
tools used to develop the
compliance forecast for
surface water systems
(SWAT and ICR Matrix
Method).
Uncertainty in ground water
compliance forecast methodologies.
Operational safety margin of
20%.
Impacts of the IDSE on the
compliance forecast for
the Preferred Regulatory
Alternative.
3.4 ................
3.7 ................
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Chapter 5,
Appendix A.
Potential effect on benefit estimate
Under-estimate
Potential effect on cost estimates
Over-estimate
Unknown impact
..................
..................
X ...................
..................
..................
X
..................
..................
X ...................
..................
..................
X
Quantified in primary analysis (addresses potential underestimate or overestimate)
Under-estimate
Over-estimate
Unknown impact
Quantified in primary analysis (addresses potential underestimate or overestimate)
Chapter 5, A
and B.
..................
..................
X ...................
..................
..................
X
5.2 ................
..................
..................
X ...................
..................
..................
X
5.3 ................
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Quantified in the primary analysis (addresses
potential underestimate)
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Quantified in the primary analysis (addresses
potential underestimate)
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TABLE VI.J–1.—EFFECTS OF UNCERTAINTIES ON NATIONAL ESTIMATES—Continued
Assumptions for which there
is uncertainty
Section with
full discussion
of uncertainty
Uncertainty in the PAR
value.
6.1.1 Appendix E.
Reduction in TTHM and
HAA5 used as proxies for
all chlorination DBPs.
DBPs have a linear nothreshold dose-response
relationship for bladder
cancer effects.
Uncertainty in benefits valuation inputs.
Benefits of reduced cancers
other than bladder cancer
are not included in the
quantitative analysis.
Value of potential reproductive and developmental
health effects avoided is
not quantified in the primary analysis.
Treatment costs do not include costs for minor
operational changes predicted by SWAT.
Median operational and
water quality parameters
considered for technology
unit costs.
Economies of scale for combination treatment technologies not considered.
Possible UV-chloramine
synergy not taken into account.
Potential low-cost alternatives to treatment not
considered.
Uncertainties in unit costs ...
6.3.3 .............
6.5.2 .............
6.7 ................
6.8 ................
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Over-estimate
Unknown impact
Potential effect on cost estimates
Under-estimate
Over-estimate
Unknown impact
Quantified in the primary analysis (addresses
range of potential effects, but true values
could lie outside range)
..................
.................. X.
..................
X.
Quantified in the primary analysis (addresses
potential underestimate or overestimate)
Quantified in a sensitivity analysis (addresses
potential underestimate)
X.
7.4.1 .............
..................
..................
..................
7.4.1 .............
..................
..................
..................
..................
7.4.1 .............
..................
..................
..................
..................
X.
7.4.1 .............
..................
..................
..................
..................
X.
7.4.2 .............
..................
..................
..................
..................
X.
7.4.3 .............
..................
..................
..................
Quantified in primary analysis (addresses potential overestimate or underestimate)
drinking water quality and may allow
some systems to avoid installing
additional technology to meet future
drinking water regulations.
Table VI.K–1 presents net benefits for
the four regulatory alternatives
evaluated by EPA. This table shows that
net benefits are positive for all four
regulatory alternatives. Generally,
analysis of net benefits is used to
identify alternatives where benefits
exceed costs, as well as the alternative
that maximizes net benefits. However,
analyses of net benefits should consider
both quantified and non-quantified
(where possible) benefits and costs. As
discussed previously with incremental
net benefits, the usefulness of this
analysis in evaluating regulatory
alternatives for the Stage 2 DBPR is
somewhat limited because many
benefits from this rule are nonquantified and non-monetized.
Table VI.K–1 shows that the Preferred
Alternative is the least cost alternative.
The Preferred Alternative has higher
mean net benefits than Alternative 1.
Alternatives 2 and 3 have higher
benefits than the Preferred Alternative
but also much greater costs. These
regulatory alternatives do not have the
risk-targeted design of the Preferred
Alternative. Rather, a large number of
systems would be required to make
treatment technology changes to meet
the stringent standards under these
regulatory alternatives. Also, because
causality has not been established
between DBP exposure and bladder
cancer, actual benefits may be as low as
zero. EPA is promulgating the preferred
regulatory alternative because the
Agency believes that such a drastic shift
in the nation’s drinking water practices
is not warranted at this time.
The Agency has determined that the
benefits of the Stage 2 DBPR justify the
costs. As discussed previously, the main
concern for the Agency and the
Advisory Committee involved in the
Stage 2 rulemaking process was to
provide more equitable protection from
DBPs across the entire distribution
system and reduce high DBP levels. The
final rule achieves this objective using
the least cost alternative by targeting
sampling locations with high DBP levels
and modifying how the annual average
DBP level is calculated. This will reduce
both average DBP levels associated with
bladder cancer (and possibly other
cancers) and peak DBP levels which are
potentially associated with reproductive
and developmental effects. In addition,
this rule may reduce uncertainty about
20:53 Jan 03, 2006
Under-estimate
6.2.1 .............
K. Benefit/Cost Determination for the
Stage 2 DBPR
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TABLE VI.K–1.—MEAN NET BENEFITS BY REGULATORY ALTERNATIVE ($MILLION)
Rule alternative
WTP for non-fatal bladder cancer cases
Mean annual
costs
Mean annual
benefits
Mean net
benefits
3 Percent Discount Rate, 25 Years
Preferred .........................................................
A1 ....................................................................
A2 ....................................................................
A3 ....................................................................
Preferred .........................................................
A1 ....................................................................
A2 ....................................................................
A3 ....................................................................
Lymphoma ......................................................
....................................................................
....................................................................
....................................................................
Bronchitis ........................................................
....................................................................
....................................................................
....................................................................
$78.8
254.1
421.7
634.2
78.8
254.1
421.7
634.2
$1,530.8
1,376.6
5,167.4
7,129.6
762.8
685.9
2,574.6
3,552.2
$1,452
1,122
4,746
6,495
684
432
2,153
2,918
$76.8
241.8
406.4
613.1
76.8
241.8
406.4
613.1
$1,246.5
1,126.4
4,227.2
5,832.4
620.7
560.8
2,104.6
2,903.8
$1,170
885
3,821
5,219
544
319
1,698
2,291
7 Percent Discount Rate, 25 Years
Preferred .........................................................
A1 ....................................................................
A2 ....................................................................
A3 ....................................................................
Preferred .........................................................
A1 ....................................................................
A2 ....................................................................
A3 ....................................................................
Lymphoma ......................................................
....................................................................
....................................................................
....................................................................
Bronchitis ........................................................
....................................................................
....................................................................
....................................................................
Notes: Estimates are discounted to 2003 and given in 2003 dollars. Based on TTHM as an indicator, Villanueva et al. (2003) for baseline risk,
and smoking/lung cancer cessation lag model. Assumes 26 percent of cases are fatal, 74 percent are non-fatal (USEPA 1999b). EPA recognizes
that benefits may be as low as zero since causality has not yet been established exposure to chlorinated water and bladder cancer.
Source: Exhibits 9.10 and 9.11, USEPA 2005a.
The Agency also compared the costs
and benefits for each regulatory
alternative by calculating which option
is the most cost-effective. The costeffectiveness analysis compares the cost
of the rule per bladder cancer case
avoided. This cost-effectiveness
measure is another way of examining
the benefits and costs of the rule, but
should not be used to compare
alternatives because an alternative with
the lowest cost per illness/death
avoided may not result in the highest
net benefits. Table VI.K–2 shows the
cost of the rule per case avoided. This
table shows that cost per case avoided
for the preferred alternative seems
favorable when compared to the
willingness to pay estimates. Additional
information about this analysis and
other methods of comparing benefits
and costs can be found in the EA
(USEPA 2005a).
TABLE VI.K–2.—ESTIMATED COST PER DISCOUNTED CASED AVOIDED 1 FOR THE REGULATORY ALTERNATIVES, USING
TTHM AS DBP INDICATOR AND SMOKING/LUNG CANCER CESSATION LAG MODEL ($MILLIONS, 2003)
Cost per case avoided
Rule alternative
3%
Preferred ..................................................................................................................................................................
Alternative 1 .............................................................................................................................................................
Alternative 2 .............................................................................................................................................................
Alternative 3 .............................................................................................................................................................
7%
$.033
1.18
0.52
0.57
$.041
1.42
0.63
0.69
1 The cost effectiveness ratios are a potentially a high estimate because regulatory costs in the numerator are not adjusted by subtracting the
avoided medical costs associated with cases avoided to produce a net cost numerator. Subtraction of theses costs would not be expected to
alter the ranking of alternatives. In the case where thresholds of maximum public expenditure per case avoided are prescribed, defining the numerator more precisely by making such adjustments would be appropriate.
Notes: In reference to conducting incremental CEA, OMB states that analyst should make sure that ‘‘When constructing and comparing incremental cost-effectiveness ratios, [analysts] should make sure that inferior alternatives identified by the principles of strong and weak dominance
are eliminated from consideration’’ (OMB Circular A–4, p. 10). Alternative 1 is dominated by the Preferred Alternative and is therefore not included in the incremental analysis. The reason for this domination is mainly that the Preferred Alternative includes IDSE and Alternative 1 does
not; and to a lesser degree because the bromate control included in Alternative 1 increases the costs but the benefits of this control are not
quantified at this time. Alternative 2 is compared directly to the Preferred Alternative (skipping Alternative 1) in this analysis. Cost per case avoided is in year 2003 dollars ($Millions), discounted for the 25 year analysis period to year 2005.
Source: Exhibit 9.14, USEPA, 2005a.
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L. Summary of Major Comments
EPA received significant public
comment on the analysis of benefits and
costs of the proposed Stage 2 DBPR in
the following areas: interpretation of
health effects studies, derivation of
benefits, use of SWAT, illustrative
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example, unanticipated risk issues, and
valuation of cancer cases avoided. The
following discussion summarizes public
comment in these areas and EPA’s
responses.
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1. Interpretation of Health Effects
Studies
EPA requested comment on the
conclusions of the cancer health effects
section and the epidemiology and
toxicology studies discussed. A number
of comments questioned the overall
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interpretation of the studies presented
by EPA. A few comments pointed out
missed studies. Commenters also asked
about concordance between cancer
epidemiology and toxicology. Some
commenters also felt EPA did not
discuss the broad range of risks from
DBPs other than the ones regulated.
The Agency continues to believe that,
although there is not a causal link, the
cancer literature points to an association
between bladder cancer and potentially
rectal and colon cancer and exposure to
chlorinated surface water. EPA has
included in today’s preamble the
literature that commenters pointed out
as missing and expands on its
discussion of non-regulated DBPs.
EPA believes that a lack of bladder
cancer effect in toxicological studies
does not negate the findings in
epidemiological studies at this time.
Tumor site concordance between
human and test animal is not necessary
to determine carcinogenic potential.
While there is evidence from human
cancer epidemiology studies that
lifetime consumption of the DBP
mixture within chlorinated surface
water poses a bladder cancer risk, the
specific causative constituents have not
been identified. EPA will continue to
evaluate new mode-of-action data as it
becomes available.
Several comments were received on
EPA’s characterization of the literature
on reproductive and developmental
health risk. Some commenters wanted
EPA to characterize reproductive and
developmental health effects more
strongly, stating that current research
shows more evidence for these effects
than described in the proposed
preamble. Others thought that EPA’s
characterization in the proposal was too
strong, and that EPA had
overemphasized these health concerns.
Some commenters noted that certain
published studies were missing from
EPA’s risk discussion.
EPA believes that the characterization
of reproductive and developmental risks
in the final Stage 2 DBPR preamble is
appropriate based on the weight of
evidence evaluation of the reproductive
and developmental epidemiology
database described in Section III.C. EPA
considered comments and incorporated
additional and recent studies into its
characterization of health risks in
today’s final preamble. While no causal
link has been established, EPA’s
evaluation of the available studies
continues to indicate a potential health
hazard that warrants additional
regulatory action beyond the Stage 1
DBPR. The inconsistencies and
uncertainties remaining in the available
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science support the incremental nature
of change in today’s rule.
EPA did not include all findings from
every study in the proposed DBPR
preamble because the intent was to
provide a summary overview and more
importantly, the Agency’s conclusions
regarding the weight of evidence. The
epidemiology literature has
inconsistencies in its findings on the
relationship between various
reproductive and developmental health
effects and DBPs. In this final preamble,
EPA describes how recent studies since
the proposal further inform the
perspective of overall risk from
exposure to DBPs. EPA continues to
believe that studies indicate a potential
hazard.
2. Derivation of Benefits
EPA received numerous comments on
the derivation of benefits from
occurrence estimates for the Stage 2
DBPR. The majority of the comments
provided addressed EPA’s use of a
cessation lag model to estimate the
timing of benefits and a PAR analysis to
estimate reduced risks. Several
commenters opposed the cessation lag
model proposed by EPA, suggesting that
EPA use a longer cessation lag period or
conduct a sensitivity analysis on the
cessation lag exponent.
In the effort to develop a cessation lag
model specific to DBPs, EPA reviewed
the available epidemiological literature
for information relating to the timing of
exposure and response, but could not
identify any studies that could, alone or
in combination, support a specific
cessation lag model for DBPs in
drinking water. Thus, in keeping with
the SAB recommendation to consider
other models in the absence of specific
cessation lag information (USEPA
2001d), EPA explored the use of
information on other carcinogens that
could be used to characterize the
influence of cessation lag in calculating
benefits. The benefit analysis for today’s
rule uses three cessation lag models,
which allows for a better
characterization of uncertainty than did
the approach used in the proposal. More
details on this analysis are in the EA
(USEPA 2005a).
Additional comments were received
on the use of PAR values derived from
epidemiology studies to determine the
number of bladder cancer cases
attributable to DBP exposure. Some
commenters remarked that there was
not sufficient evidence in the
epidemiology studies used to develop a
reliable PAR estimate. A key issue
expressed in the comments was that
studies that developed the PAR
estimates did not adequately control for
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465
confounders. One commenter supported
EPA review of the Villanueva (2003)
meta-analysis, stating that this was the
best available data on the issue.
EPA revised the methodology for
calculating PAR values for bladder
cancer associated with exposure to
chlorinated drinking water by
considering three different analytical
approaches as described in Section
V.B.2. EPA used the PAR values from all
three approaches to estimate the number
of bladder cancer cases ultimately
avoided annually as a result of the Stage
2 DBPR. Taken together, the three
approaches provide a reasonable
estimate of the range of potential risk.
For simplicity, EPA used the Villanueva
et al. (2003) study to calculate the
annual benefits of the rule. The benefit
estimates derived from Villanueva et al.
(2003) capture a substantial portion of
the overall range of results, reflecting
the uncertainty in both the underlying
OR and PAR values, as well as the
uncertainty in DBP reductions for Stage
2. More details on the PAR analysis can
be found in the EA (USEPA 2005a).
3. Use of SWAT
Comments received on the use of
SWAT for the compliance forecast
claimed that the model probably
underestimates DBP occurrence levels
and hence underestimates compliance
costs. Other commenters supported
EPA’s occurrence estimation methods
and results. Some commenters added
that monitoring under the IDSE will
produce different results than
monitoring for the ICR and that SWAT
did not capture these changes.
EPA describes in detail the limitations
of SWAT as well as all assumptions and
uncertainties associated with the model
in the EA published with today’s rule.
EPA believes that, for the reasons stated
below, the standard compliance forecast
method using SWAT, as developed
during the M-DBP FACA, provides a
reasonable prediction of national
treatment changes and resulting DBP
levels anticipated for the Stage 2 DBPR:
1. SWAT predictive equations for
TTHM and HAA5 were calibrated to
ICR-observed TTHM and HAA5 data.
2. SWAT estimates are based on 12
months of influent water quality data,
treatment train information, and related
characteristics for the 273 ICR surface
water plants. EPA believes the ICR data
provide a robust basis for the
compliance forecast as it represents
significant variability with respect to
factors influencing DBP formation,
including temperature, residence time,
and geographical region.
3. EPA uses a ‘‘delta’’ approach to
reduce the impact of uncertainty in
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SWAT’s predictive equations for TTHM
and HAA5. Under this approach, EPA 1)
estimates the difference in technology
and TTHM and HAA5 concentration
predictions between pre-Stage 1 and
post-Stage 1; 2) estimates the difference
in technology and TTHM and HAA5
concentration predictions between preStage 1 and post-Stage 2; and 3)
subtracts the result of the first estimate
from the second estimate to predict the
impacts between Stage 1 and Stage 2.
Since each predictive estimate has bias
in the same direction, EPA believes that
this methodology minimized overall
predictive error.
In response to commenters concerns
about potential uncertainties in the
SWAT predictions, EPA also developed
the ‘‘ICR Matrix Method.’’ The ICR
Matrix Method uses TTHM and HAA5
data from the ICR to estimate the
percent of plants changing technology to
comply with the Stage 2 DBPR and the
resulting DBP reduction. The EA
includes a detailed description of the
ICR Matrix Method (USEPA 2005a). In
the analysis for today’s rule, EPA gives
equal weight to SWAT and ICR Matrix
Method predictions in estimating Stage
2 compliance forecasts and resultant
reductions in DBP exposure. The ICR
Matrix Method is also used to estimate
reductions in the occurrence of peak
TTHM and HAA5 concentrations
because SWAT-predicted TTHM and
HAA5 concentrations are valid only
when considering national averages, not
at the plant level.
EPA revised the Stage 2 DBPR
compliance forecast methodology to
quantify the potential impacts of the
IDSE for large and medium surface
water systems. For these systems, EPA
predicted compliance implications
using a safety margin of both 20 and 25
percent based on an analysis of spatial
variability in TTHM and HAA5
occurrence. EPA assigned equal
probability to the 20 and 25 percent
safety margins because both alternatives
are considered equally plausible. These
changes result in a wider uncertainty
range for the compliance cost estimates
than under the EA of the proposed rule.
EPA assumes the 20 percent operational
safety margin accounts for variability in
small surface water systems and all
ground water systems. Small systems
are not expected to find significantly
higher levels that affect their
compliance as a result of the IDSE
because their distribution systems are
not as complex as large systems.
Additionally, the IDSE is not expected
to significantly impact the compliance
forecast for ground water systems
because they have more consistent
source water quality and do not
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experience significant year-to-year
variability in TTHM and HAA5
occurrence.
As some commenters noted, any
underestimation in costs as a result of
the compliance forecast is associated
with an underestimation in the benefits.
Accordingly, EPA adjusted both cost
and benefits estimates based on the ICR
Matrix Method and the impact of the
IDSE for the upper end of the
compliance forecast range.
4. Illustrative Example
Many comments were received on the
illustrative calculation of fetal loss
benefits included in the proposed EA.
Many commenters recommended that
EPA remove this calculation because of
uncertainties in the underlying data.
Other commenters, however, expressed
support for this calculation because of
the magnitude of potential benefits, and
suggested that EPA include these
benefits in its primary analysis.
EPA believes that the reproductive
and developmental epidemiologic data,
although not conclusive, are suggestive
of potential health effects in humans
exposed to DBPs. EPA does not believe
the available evidence provides an
adequate basis for quantifying potential
reproductive and developmental risks.
Nevertheless, given the widespread
nature of exposure to DBPs, the
importance our society places on
reproductive and developmental health,
and the large number of fetal losses
experienced each year in the U.S.
(nearly 1 million), the Agency believes
that it is appropriate to provide some
quantitative indication of the potential
risk suggested by some of the published
results on reproductive and
developmental endpoints, despite the
absence of certainty regarding a causal
link between disinfection byproducts
and these risks and the inconsistencies
between studies. However, the Agency
is unable at this time to either develop
a specific estimate of the value of
avoiding fetal loss or to use a benefit
transfer methodology to estimate the
value from studies that address other
endpoints.
5. Unanticipated Risk Issues
Comments were received that
expressed concern about unanticipated
risks that could result from the
proposed Stage 2 DBPR. Several
commenters remarked that regulation of
TTHM and HAA5 would not control
levels of other DBPs that may be more
toxic than these indicator compounds,
such as NDMA. Some commenters
supported future research on the
potential health effects of other DBPs.
Other comments suggested that EPA
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further consider these risks when
developing the final Stage 2 DBPR.
EPA has addressed the occurrence of
other DBPs in Section VI.H of this
document and in the EA (USEPA
2005a). Levels of some DBPs may
increase because of treatment changes
anticipated as a result of today’s rule.
However, these DBPs generally occur at
much lower levels than TTHM and
HAA5, often more than an order of
magnitude less (USEPA 2005f, Weinberg
et al. 2002). For NDMA, studies have
shown formation in both chlorinated
and chloraminated systems (Barrett et
al. 2003). The uncertainties surrounding
NDMA formation make determinations
regarding the impact of the Stage 2
DBPR difficult. In addition, other routes
of exposure appear to be more
significant than drinking water. Dietary
sources of NDMA include preserved
meat and fish products, beer and
tobacco. EPA is looking at calculating
the relative source contribution of these
routes of exposure compared to drinking
water.
EPA continues to support the use of
TTHM and HAA5 as indicators for DBP
regulation. The presence of TTHM and
HAA5 is representative of the
occurrence of many other chlorination
DBPs; thus, a reduction in the TTHM
and HAA5 generally indicates an overall
reduction of DBPs. EPA also supports
additional research on unregulated and
unknown DBPs to ensure continual
public health protection.
6. Valuation of Cancer Cases Avoided
A number of commenters remarked
on the valuation of cancer cases
avoided. Some commenters supported
the use of value of statistical life (VSL)
analysis in monetizing the benefits of
fatal bladder cancer cases avoided.
Comments were also received in
support of the addition of expected
medical costs for treating fatal bladder
cancer cases to the VSL estimates. Other
commenters recommended that EPA
further review the use of willingness-topay estimates used to value the nonfatal cancer cases avoided. These
comments stated concern over the
similarity of bronchitis and lymphoma
to bladder cancer and the resulting
limitation of benefits transfer.
EPA thanks commenters for
expressing support of the use of VSL
and valuation of fatal bladder cancer
cases. EPA acknowledges that the
willingness to pay (WTP) to avoid
curable lymphoma or chronic bronchitis
is not a perfect substitute for the WTP
to avoid a case of non-fatal bladder
cancer. However, non-fatal internal
cancers, regardless of type, generally
present patients with very similar
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treatment, health, and long-term quality
of life implications, including surgery,
radiation or chemotherapy treatments
(with attendant side effects), and
generally diminished vitality over the
duration of the illness. In the absence of
more specific WTP studies, EPA
believes the WTP values for avoiding a
case of curable lymphoma or a case of
chronic bronchitis provides a
reasonable, though not definitive,
substitute for the value of avoiding nonfatal bladder cancer.
VII. Statutory and Executive Order
Reviews
A. Executive Order 12866: Regulatory
Planning and Review
Under Executive Order 12866, [58 FR
51735, (October 4, 1993)] the Agency
must determine whether the regulatory
action is ‘‘significant’’ and therefore
subject to OMB review and the
requirements of the Executive Order.
The Order defines ‘‘significant
regulatory action’’ as one that is likely
to result in a rule that may:
(1) Have an annual effect on the
economy of $100 million or more or
adversely affect in a material way the
economy, a sector of the economy,
productivity, competition, jobs, the
environment, public health or safety, or
State, local, or Tribal governments or
communities;
(2) Create a serious inconsistency or
otherwise interfere with an action taken
or planned by another agency;
(3) Materially alter the budgetary
impact of entitlements, grants, user fees,
or loan programs or the rights and
obligations of recipients thereof; or
(4) Raise novel legal or policy issues
arising out of legal mandates, the
President’s priorities, or the principles
set forth in the Executive Order.
Pursuant to the terms of Executive
Order 12866, it has been determined
that this rule is a ‘‘significant regulatory
action.’’ As such, this action was
submitted to OMB for review. Changes
made in response to OMB suggestions or
recommendations will be documented
in the public record.
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B. Paperwork Reduction Act
The Office of Management and Budget
(OMB) has approved the information
collection requirements contained in
this rule under the provisions of the
Paperwork Reduction Act, 44 U.S.C.
3501 et seq. and has assigned OMB
control number 2040–0265 (USEPA
2005n).
The information collected as a result
of this rule will allow the States and
EPA to determine appropriate
requirements for specific systems, and
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to evaluate compliance with the rule.
For the first three years after Stage 2
DBPR promulgation, the major
information requirements involve
monitoring activities, which include
conducting the IDSE and submission of
the IDSE report, and tracking
compliance. The information collection
requirements are mandatory (Part 141),
and the information collected is not
confidential.
The estimate of annual average
burden hours for the Stage 2 DBPR for
systems and States is 228,529 hours.
This estimate covers the first three years
of the Stage 2 DBPR and most of the
IDSE (small system reports are not due
until the fourth year). The annual
average aggregate cost estimate is $9.8
million for operation and maintenance
as a purchase of service for lab work and
$6.6 million is associated with labor.
The annual burden hour per response is
4.18 hours. The frequency of response
(average responses per respondent) is
7.59 annually. The estimated number of
likely respondents is 7,202 per year (the
product of burden hours per response,
frequency, and respondents does not
total the annual average burden hours
due to rounding). Because disinfecting
systems have already purchased basic
monitoring equipment to comply with
the Stage 1 DBPR, EPA assumes no
capital start-up costs are associated with
the Stage 2 DBPR ICR.
Burden means the total time, effort, or
financial resources expended by persons
to generate, maintain, retain, or disclose
or provide information to or for a
Federal agency. This includes the time
needed to review instructions; develop,
acquire, install, and utilize technology
and systems for the purposes of
collecting, validating, and verifying
information, processing and
maintaining information, and disclosing
and providing information; adjust the
existing ways to comply with any
previously applicable instructions and
requirements; train personnel to be able
to respond to a collection of
information; search data sources;
complete and review the collection of
information; and transmit or otherwise
disclose the information.
An agency may not conduct or
sponsor, and a person is not required to
respond to a collection of information
unless it displays a currently valid OMB
control number. The OMB control
numbers for EPA’s regulations in 40
CFR are listed in 40 CFR part 9. In
addition, EPA is amending the table in
40 CFR part 9 of currently approved
OMB control numbers for various
regulations to list the regulatory
citations for the information
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467
requirements contained in this final
rule.
C. Regulatory Flexibility Act
The Regulatory Flexibility Act (RFA)
generally requires an agency to prepare
a regulatory flexibility analysis for any
rule subject to notice and comment
rulemaking requirements under the
Administrative Procedure Act or other
statute unless the agency certifies that
the rule will not have a significant
economic impact on a substantial
number of small entities. Small entities
include small businesses, small
organizations, and small governmental
jurisdictions.
The RFA provides default definitions
for each type of small entity. Small
entities are defined as: (1) A small
business as defined by the Small
Business Administrations’s (SBA)
regulations at 13 CFR 121.201; (2) a
small governmental jurisdiction that is a
government of a city, county, town,
school district or special district with a
population of less than 50,000; and (3)
a small organization that is any ‘‘not-forprofit enterprise which is independently
owned and operated and is not
dominant in its field.’’ However, the
RFA also authorizes an agency to use
alternative definitions for each category
of small entity, ‘‘which are appropriate
to the activities of the agency’’ after
proposing the alternative definition(s) in
the Federal Register and taking
comment. 5 U.S.C. 601(3)–(5). In
addition, to establish an alternative
small business definition, agencies must
consult with SBA’s Chief Council for
Advocacy.
For purposes of assessing the impacts
of today’s rule on small entities, EPA
considered small entities to be public
water systems serving 10,000 or fewer
persons. As required by the RFA, EPA
proposed using this alternative
definition in the Federal Register (63 FR
7620, February 13, 1998), requested
public comment, consulted with the
Small Business Administration (SBA),
and finalized the alternative definition
in the Consumer Confidence Reports
regulation (63 FR 44511, August 19,
1998). As stated in that Final Rule, the
alternative definition is applied to this
regulation as well.
After considering the economic
impacts of today’s final rule on small
entities, I certify that this action will not
have a significant economic impact on
a substantial number of small entities.
The small entities regulated by this final
rule are PWSs serving fewer than 10,000
people. We have determined that 92
small surface water and ground water
under the direct influence of surface
water (GWUDI) systems (or 2.16% of all
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small surface water and GWUDI systems
affected by the Stage 2 DBPR) will
experience an impact of 1% or greater
of average annual revenues. Of the 92,
40 small surface water and GWUDI
systems (or 0.94% of all small surface
water and GWUDI systems affected by
the Stage 2 DBPR) will experience an
impact of 3% or greater of average
annual revenues. Further, 354 small
ground water systems (or 1.02% of all
small ground water systems affected by
the Stage 2 DBPR) will experience an
impact of 1% or greater of average
annual revenues. Of the 354, 45 small
ground water systems (or 0.13% of all
small ground water systems affected by
the Stage 2 DBPR) will experience an
impact of 3% or greater of average
annual revenues.
Although this final rule will not have
a significant economic impact on a
substantial number of small entities,
EPA nonetheless has tried to reduce the
impact of this rule on small entities. The
Stage 2 DBPR contains a number of
provisions to minimize the impact of
the rule on systems generally, and on
small systems in particular. For
example, small systems have a longer
time frame to comply with requirements
than large systems (see § 141.600(c) and
§ 141.620(c)). The final rule determines
monitoring frequency based on
population rather than plant-based
monitoring requirements (see § 141.605
and § 141.621(a)) as proposed. Small
systems will also have to take fewer
samples than large systems due to the
40/30 waiver (see § 141.603(a)), for
which small, ground water systems are
expected to be able to qualify, and the
very small system waiver (see
§ 141.604).
Funding may be available from
programs administered by EPA and
other Federal agencies to assist small
PWSs in complying with the Stage 2
DBPR. The Drinking Water State
Revolving Fund (DWSRF) assists PWSs
with financing the costs of
infrastructure needed to achieve or
maintain compliance with SDWA
requirements. Through the DWSRF,
EPA awards capitalization grants to
States, which in turn can provide lowcost loans and other types of assistance
to eligible PWSs. Loans made under the
program can have interest rates between
0 percent and market rate and
repayment terms of up to 20 years.
States prioritize funding based on
projects that address the most serious
risks to human health and assist PWSs
most in need. Congress provided the
DWSRF program $8 billion for fiscal
years 1997 through 2004.
The DWSRF places an emphasis on
small and disadvantaged communities.
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States must provide a minimum of 15%
of the available funds for loans to small
communities. A State has the option of
providing up to 30% of the grant
awarded to the State to furnish
additional assistance to State-defined
disadvantaged communities. This
assistance can take the form of lower
interest rates, principal forgiveness, or
negative interest rate loans. The State
may also extend repayment terms of
loans for disadvantaged communities to
up to 30 years. A State can set aside up
to 2% of the grant to provide technical
assistance to PWSs serving communities
with populations fewer than 10,000.
In addition to the DWSRF, money is
available from the Department of
Agriculture’s Rural Utility Service
(RUS) and Housing and Urban
Development’s Community
Development Block Grant (CDBG)
program. RUS provides loans,
guaranteed loans, and grants to improve,
repair, or construct water supply and
distribution systems in rural areas and
towns of up to 10,000 people. In fiscal
year 2003, RUS had over $1.5 billion of
available funds for water and
environmental programs. The CDBG
program includes direct grants to States,
which in turn are awarded to smaller
˜
communities, rural areas, and colonas in
Arizona, California, New Mexico, and
Texas and direct grants to U.S.
territories and trusts. The CDBG budget
for fiscal year 2003 totaled over $4.4
billion.
Although not required by the RFA to
convene a Small Business Advocacy
Review (SBAR) Panel because EPA
determined that the proposed rule
would not have a significant economic
impact on a substantial number of small
entities, EPA did convene a panel to
obtain advice and recommendations
from representatives of the small
entities potentially subject to this rule’s
requirements. For a description of the
SBAR Panel and stakeholder
recommendations, please see the
proposed rule (USEPA 2003a).
D. Unfunded Mandates Reform Act
Title II of the Unfunded Mandates
Reform Act of 1995 (UMRA), Public
Law 104–4, establishes requirements for
Federal agencies to assess the effects of
their regulatory actions on State, local,
and Tribal governments and the private
sector. Under section 202 of the UMRA,
EPA generally must prepare a written
statement, including a cost-benefit
analysis, for proposed and final rules
with ‘‘Federal mandates’’ that may
result in expenditures to State, local and
Tribal governments, in the aggregate, or
to the private sector, of $100 million or
more in any one year. Before
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promulgating an EPA rule for which a
written statement is needed, section 205
of the UMRA generally requires EPA to
identify and consider a reasonable
number of regulatory alternatives and
adopt the least costly, most costeffective or least burdensome alternative
that achieves the objectives of the rule.
The provisions of section 205 do not
apply when they are inconsistent with
applicable law. Moreover, section 205
allows EPA to adopt an alternative other
than the least costly, most cost-effective
or least burdensome alternative if the
Administrator publishes with the final
rule an explanation why that alternative
was not adopted. Before EPA establishes
any regulatory requirements that may
significantly or uniquely affect small
governments, including Tribal
governments, it must have developed
under section 203 of the UMRA a small
government agency plan. The plan must
provide for notifying potentially
affected small governments, enabling
officials of affected small governments
to have meaningful and timely input in
the development of EPA regulatory
proposals with significant Federal
intergovernmental mandates, and
informing, educating, and advising
small governments on compliance with
the regulatory requirements.
EPA has determined that this rule
may contain a Federal mandate that
results in expenditures of $100 million
or more for the State, Local, and Tribal
governments, in the aggregate in the
private sector in any one year. While the
annualized costs fall below the $100
million threshold, the costs in some
future years may be above the $100
million mark as public drinking water
systems make capital investments and
finance these through bonds, loans, and
other means. EPA’s year by year cost
tables do not reflect that investments
through bonds, loans, and other means
spread out these costs over many years.
The cost analysis in general does not
consider that some systems may be
eligible for financial assistance such as
low-interest loans and grants through
such programs as the Drinking Water
State Revolving Fund.
As noted earlier, today’s final rule is
promulgated pursuant to section 1412
(b)(1)(A) of the Safe Drinking Water Act
(SDWA), as amended in 1996, which
directs EPA to promulgate a national
primary drinking water regulation for a
contaminant if EPA determines that the
contaminant may have an adverse effect
on the health of persons, occurs in
PWSs with a frequency and at levels of
public health concern, and regulation
presents a meaningful opportunity for
health risk reduction.
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Section VI of this preamble discusses
the cost and benefits associated with the
469
Stage 2 DBPR. Details are presented in
the Economic Analysis (USEPA 2005a).
TABLE VII.D–1—PUBLIC AND PRIVATE COSTS FOR THE STAGE 2 DBPR (ANNUALIZED AT 3 AND 7 PERCENT, $MILLIONS)
3% discount rate
Surface Water Systems Costs ................................................
Ground Water Systems Costs .................................................
State Costs ..............................................................................
Tribal Costs ..............................................................................
Total Public .......................................................................
Surface Water Systems Costs ................................................
Ground Water Systems Costs .................................................
Total Private .....................................................................
Grand total .................................................................
7% discount rate
$41.4
20.3
1.7
0.4
63.8
6.4
8.5
15.0
78.8
Percent of 3%
grand total costs
(percent)
$41.2
19.2
1.7
0.4
62.5
6.3
8.0
14.3
76.8
53
26
2
1
81
8
11
19
100
Percent of 7%
grand total costs
(percent)
54
25
2
0
81
8
10
19
100
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Note: Detail may not add due to independent rounding. Estimates are discounted to 2003 and given in 2003 dollars.
Source: Exhibits 3.2 and 7.5, USEPA 2005a.
To meet the UMRA requirement in
section 202, EPA analyzed future
compliance costs and possible
disproportionate budgetary effects. The
Agency believes that the cost estimates
and regulatory alternatives indicated
earlier and discussed in more detail in
section VI of this preamble, accurately
characterize future compliance costs of
today’s rule.
In analyzing disproportionate
impacts, EPA considered the impact on
(1) different regions of the United States,
(2) State, local, and Tribal governments,
(3) urban, rural and other types of
communities, and (4) any segment of the
private sector. This analysis is presented
in Chapter 7of the Economic Analysis
(USEPA 2005a). EPA analyzed four
regulatory alternatives and selected the
least costly of these in accordance with
UMRA Section 205.
EPA has determined that the Stage 2
DBPR contains no regulatory
requirements that might significantly or
uniquely affect small governments. The
Stage 2 DBPR affects all size systems. As
described in section VII.C, EPA has
certified that today’s rule will not have
a significant economic impact on a
substantial number of small entities.
Average annual expenditures for small
CWSs to comply with the Stage 2 DBPR
range from $27.7 to $26.1 million at a
3 and 7 percent discount rate,
respectively.
Consistent with the intergovernmental
consultation provisions of section 204 of
the UMRA and Executive Order 12875,
‘‘Enhancing the Intergovernmental
Partnership,’’ EPA has already initiated
consultations with the governmental
entities affected by this rule. The
consultations are described in the
proposed rule (68 FR 49654, August 18,
2003).
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E. Executive Order 13132: Federalism
Executive Order 13132, entitled
‘‘Federalism’’ (64 FR 43255, August 10,
1999), requires EPA to develop an
accountable process to ensure
‘‘meaningful and timely input by State
and local officials in the development of
regulatory policies that have federalism
implications.’’ ‘‘Policies that have
federalism implications’’ is defined in
the Executive Order to include
regulations that have ‘‘substantial direct
effects on the States, on the relationship
between the national government and
the States, or on the distribution of
power and responsibilities among the
various levels of government.’’
This final rule does not have
federalism implications. It will not have
substantial direct effects on the States,
on the relationship between national
government and the States, or on the
distribution of power and
responsibilities among various levels of
government, as specified in Executive
Order 13132. The final rule has onetime costs for implementation of
approximately $7.8 million. Thus,
Executive Order 13132 does not apply
to this rule.
Although section 6 of Executive Order
13132 does not apply to this rule, in the
spirit of Executive Order 13132, and
consistent with EPA policy to promote
communications between EPA and State
and local governments, EPA nonetheless
specifically solicited comment on the
proposed rule from State and local
officials and did consult with State and
local officials in developing this rule. A
description of that consultation can be
found in the preamble to the proposed
rule, 68 FR 49548, (August 18, 2003).
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F. Executive Order 13175: Consultation
and Coordination With Indian Tribal
Governments
Executive Order 13175, entitled
‘‘Consultation and Coordination with
Indian Tribal Governments’’ (65 FR
67249, November 9, 2000), requires EPA
to develop ‘‘an accountable process to
ensure meaningful and timely input by
tribal officials in the development of
regulatory policies that have tribal
implications.’’ Under Executive Order
13175, EPA may not issue a regulation
that has Tribal implications, that
imposes substantial direct compliance
costs, and that is not required by statute,
unless the Federal government provides
the funds necessary to pay the direct
compliance costs incurred by Tribal
governments, or EPA consults with
Tribal officials early in the process of
developing the proposed regulation and
develops a Tribal summary impact
statement.
EPA has concluded that this final rule
may have Tribal implications, because it
may impose substantial direct
compliance costs on Tribal
governments, and the Federal
government will not provide the funds
necessary to pay those costs.
Accordingly, EPA provides the
following Tribal summary impact
statement as required by section 5(b).
EPA provides further detail on Tribal
impact in the Economic Analysis
(USEPA 2005a). Total Tribal costs are
estimated to be approximately $391,773
per year (at a 3 percent discount rate)
and this cost is distributed across 755
Tribal systems. The cost for individual
systems depend on system size and
source water type. Of the 755 Tribes that
may be affected in some form by the
Stage 2 DBPR, 654 use ground water as
a source and 101 systems use surface
water or GWUDI. Since the majority of
Tribal systems are ground water systems
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serving fewer than 500 people,
approximately 15.6 percent of all Tribal
systems will have to conduct an IDSE.
As a result, the Stage 2 DBPR is most
likely to have an impact on Tribes using
surface water or GWUDI serving more
than 500 people.
EPA consulted with Tribal officials
early in the process of developing this
regulation to permit them to have
meaningful and timely input into its
development. Moreover, in the spirit of
Executive Order 13175, and consistent
with EPA policy to promote
communications between EPA and
Tribal governments, EPA specifically
solicited comment on the proposed rule
from Tribal officials.
As required by section 7(a), EPA’s
Tribal Consultation Official has certified
that the requirements of the Executive
Order has been met in a meaningful and
timely manner. A copy of this
certification has been included in the
docket for this rule.
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G. Executive order 13045: Protection of
Children From Environmental Health
Risks and Safety Risks
Executive Order 13045: ‘‘Protection of
Children from Environmental Health
Risks and Safety Risks’’ (62 FR 19885,
April 23, 1997) applies to any rule that:
(1) is determined to be ‘‘economically
significant’’ as defined under 12866,
and; (2) concerns an environmental
health or safety risk that EPA has reason
to believe may have a disproportionate
effect on children. If the regulatory
action meets both criteria, the Agency
must evaluate the environmental health
or safety effects of the planned rule on
children, and explain why the planned
regulation is preferable to other
potentially effective and reasonably
feasible alternatives considered by the
Agency.
While this final rule is not subject to
the Executive Order because it is not
economically significant as defined in
Executive Order 12866, EPA
nonetheless has reason to believe that
the environmental health or safety risk
(i.e., the risk associated with DBPs)
addressed by this action may have a
disproportionate effect on children. EPA
believes that the Stage 2 DBPR will
result in greater risk reduction for
children than for the general
population. The results of the
assessments are contained in Section
VI.I of this preamble and in the
Economic Analysis (USEPA 2005a). A
copy of all documents has been placed
in the public docket for this action.
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H. Executive Order 13211: Actions
Concerning Regulations That
Significantly Affect Energy Supply,
Distribution, or Use
This rule is not a ‘‘significant energy
action’’ as defined in Executive Order
13211, ‘‘Actions Concerning Regulations
That Significantly Affect Energy Supply,
Distribution, or Use’’ (66 FR 28355, May
22, 2001) because it is not likely to have
a significant adverse effect on the
supply, distribution, or use of energy.
This determination is based on the
following analysis.
The first consideration is whether the
Stage 2 DBPR would adversely affect the
supply of energy. The Stage 2 DBPR
does not regulate power generation,
either directly or indirectly. The public
and private utilities that the Stage 2
DBPR regulates do not, as a rule,
generate power. Further, the cost
increases borne by customers of water
utilities as a result of the Stage 2 DBPR
are a low percentage of the total cost of
water, except for a very few small
systems that might install advanced
technologies that must spread that cost
over a narrow customer base. Therefore,
the customers that are power generation
utilities are unlikely to face any
significant effects as a result of the Stage
2 DBPR. In sum, the Stage 2 DBPR does
not regulate the supply of energy, does
not generally regulate the utilities that
supply energy, and is unlikely
significantly to affect the customer base
of energy suppliers. Thus, the Stage 2
DBPR would not translate into adverse
effects on the supply of energy.
The second consideration is whether
the Stage 2 DBPR would adversely affect
the distribution of energy. The Stage 2
DBPR does not regulate any aspect of
energy distribution. The utilities that are
regulated by the Stage 2 DBPR already
have electrical service. As derived later
in this section, the final rule is projected
to increase peak electricity demand at
water utilities by only 0.009 percent.
Therefore, EPA estimates that the
existing connections are adequate and
that the Stage 2 DBPR has no
discernable adverse effect on energy
distribution.
The third consideration is whether
the Stage 2 DBPR would adversely affect
the use of energy. Because some
drinking water utilities are expected to
add treatment technologies that use
electrical power, this potential impact is
evaluated in more detail. The analyses
that underlay the estimation of costs for
the Stage 2 DBPR are national in scope
and do not identify specific plants or
utilities that may install treatment in
response to the rule. As a result, no
analysis of the effect on specific energy
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suppliers is possible with the available
data. The approach used to estimate the
impact of energy use, therefore, focuses
on national-level impacts. The analysis
estimates the additional energy use due
to the Stage 2 DBPR and compares that
analysis to the national levels of power
generation in terms of average and peak
loads.
The first step in the analysis is to
estimate the energy used by the
technologies expected to be installed as
a result of the Stage 2 DBPR. Energy use
is not directly stated in Technologies
and Costs for the Final Long Term 2
Enhanced Surface Water Treatment Rule
and Final Stage 2 Disinfectants and
Disinfection Byproducts Rule (USEPA
2005g), but the annual cost of energy for
each technology addition or upgrade
necessitated by the Stage 2 DBPR is
provided. An estimate of plant-level
energy use is derived by dividing the
total energy cost per plant for a range of
flows by an average national cost of
electricity of $0.076/ kilowatt hours per
year (kWh/yr) (USDOE 2004a). These
calculations are shown in detail in the
Economic Analysis (USEPA 2005a). The
energy use per plant for each flow range
and technology is then multiplied by
the number of plants predicted to install
each technology in a given flow range.
The energy requirements for each flow
range are then added to produce a
national total. No electricity use is
subtracted to account for the
technologies that may be replaced by
new technologies, resulting in a
conservative estimate of the increase in
energy use. The incremental national
annual energy usage is 0.12 million
megawatt-hours (MWh).
According to the U.S. Department of
Energy’s Information Administration,
electricity producers generated 3,848
million MWh of electricity in 2003
(USDOE 2004b). Therefore, even using
the highest assumed energy use for the
Stage 2 DBPR, the rule when fully
implemented would result in only a
0.003 percent increase in annual average
energy use.
In addition to average energy use, the
impact at times of peak power demand
is important. To examine whether
increased energy usage might
significantly affect the capacity margins
of energy suppliers, their peak season
generating capacity reserve was
compared to an estimate of peak
incremental power demand by water
utilities.
Both energy use and water use peak
in the summer months, so the most
significant effects on supply would be
seen then. In the summer of 2003, U.S.
generation capacity exceeded
consumption by 15 percent, or
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approximately 160,000 MW (USDOE
2004b). Assuming around-the-clock
operation of water treatment plants, the
total energy requirement can be divided
by 8,760 hours per year to obtain an
average power demand of 13.28 MW. A
more detailed derivation of this value is
shown in the Economic Analysis
(USEPA 2005a). Assuming that power
demand is proportional to water flow
through the plant and that peak flow
can be as high as twice the average daily
flow during the summer months, about
26.55 MW could be needed for
treatment technologies installed to
comply with the Stage 2 DBPR. This is
only 0.017 percent of the capacity
margin available at peak use.
Although EPA recognizes that not all
areas have a 15 percent capacity margin
and that this margin varies across
regions and through time, this analysis
reflects the effect of the rule on national
energy supply, distribution, and use.
While certain areas, notably California,
have experienced shortfalls in
generating capacity in the recent past, a
peak incremental power requirement of
26.55 MW nationwide is not likely to
significantly change the energy supply,
distribution, or use in any given area.
Considering this analysis, EPA has
concluded that Stage 2 DBPR will not
have any significant effect on the use of
energy, based on annual average use and
on conditions of peak power demand.
I. National Technology Transfer and
Advancement Act
As noted in the proposed rule,
Section 12(d) of the National
Technology Transfer and Advancement
Act of 1995 (‘‘NTTAA’’), Public Law
104–113, section 12(d) (15 U.S.C. 272
note) directs EPA to use voluntary
consensus standards in its regulatory
activities unless to do so would be
inconsistent with applicable law or
otherwise impractical. Voluntary
consensus standards are technical
standards (e.g., materials specifications,
test methods, sampling procedures, and
business practices) that are developed or
adopted by voluntary consensus
standard bodies. The NTTAA directs
EPA to provide Congress, through OMB,
explanations when the Agency decides
not to use available and applicable
voluntary consensus standards.
This rulemaking involves technical
standards. EPA has decided to use two
voluntary consensus methods for HAA5
(Standard Method 6251 B, 1998 in the
20th Edition of Standard Methods for
the Examination of Water and
Wastewater and Standard Method 6251
B–94, 1994 available at https://
www.standardmethods.org). In addition
to these two consensus methods, EPA is
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also approving EPA Method 552.3 for
HAA5, which also can be used to
measure three unregulated HAAs that
are not included in the consensus
methods. The unregulated HAAs are
included in the EPA method because
some water systems monitor for them in
order to better understand their
treatment processes and provide greater
public health protection. EPA is
approving two voluntary consensus
standards for daily monitoring for
chlorite (Standard Method 4500–ClO2 E,
1998, in the 20th Edition of Standard
Methods for the Examination of Water
and Wastewater and Standard Method
4500–ClO2 E–00, 2000, available at
https://www.standardmethods.org). EPA
Method 327.0, Revision 1.1 is also being
approved for daily monitoring for both
chlorite and chlorine dioxide in order to
provide an alternative to the titration
procedure that is required in the
Standard Methods. EPA is approving a
method from American Society for
Testing and Materials International for
bromate, chlorite and bromide analyses
(ASTM D 6581–00, 2000, ASTM
International. Annual Book of ASTM
Standards, Volume 11.01, American
Society for Testing and Materials
International, 2001 or any year
containing the cited version of the
method may be used). EPA is also
approving three EPA methods (EPA
Methods 317.0 Revision 2.0, 321.8, and
326.0) that provide greater sensitivity
and selectivity for bromate than the
ASTM consensus standard. These EPA
methods are required in order to
provide better process control for water
systems using ozone in the treatment
process and to allow for a reduced
monitoring option. EPA Methods 317.0
Revision 2.0 and 326.0 can also be used
to determine chlorite and bromide.
Today’s action approves eight voluntary
consensus standards for determining
free, combined, and total chlorine (SM
4500–Cl D, SM 4500–Cl F, and 4500–Cl
G, 1998, in the 20th Edition of Standard
Methods for the Examination of Water
and Wastewater and SM 4500–Cl D–00,
SM 4500–Cl F–00, and 4500–Cl G–00,
2000 available at https://
www.standardmethods.org and ASTM D
1253–86(96), 1996, ASTM International,
Annual Book of ASTM Standards,
Volume 11.01, American Society for
Testing and Materials International,
1996 or any year containing the cited
version of the method may be used and
ASTM D 1253–03, 2003, ASTM
International, Annual Book of ASTM
Standards, Volume 11.01, American
Society for Testing and Materials
International, 2004 or any year
containing the cited version of the
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471
method may be used). EPA is approving
four standards for determining total
chlorine (SM 4500–Cl E and SM 4500–
Cl I, 1998, in the 20th Edition of
Standard Methods for the Examination
of Water and Wastewater and SM 4500–
Cl E–00 and SM 4500–Cl I–00, 2000
available at https://
www.standardmethods.org). Two
standards for determining free chlorine
are approved in today’s rule (SM 4500–
Cl H, 1998, in the 20th Edition of
Standard Methods for the Examination
of Water and Wastewater and SM 4500–
Cl H–00, 2000 available at https://
www.standardmethods.org). Today’s
action approves three voluntary
consensus standards for measuring
chlorine dioxide (4500–ClO2 D and
4500–ClO2 E, 1998, in the 20th Edition
of Standard Methods for the
Examination of Water and Wastewater
and 4500–ClO2 E–00, 2000 available at
https://www.standardmethods.org). EPA
is approving six standards for
determining TOC and DOC (SM 5310 B,
SM 5310 C, and SM 5310 D, 1998, in the
20th Edition of Standard Methods for
the Examination of Water and
Wastewater and SM 5310 B–00, SM
5310 C–00, and SM 5310 D–00, 2000
available at https://
www.standardmethods.org). Two
standards for determining UV254 are
approved in today’s rule (SM 5910 B,
1998, in the 20th Edition of Standard
Methods for the Examination of Water
and Wastewater and SM 5910 B–00,
2000 available at https://
www.standardmethods.org). EPA is also
approving EPA Method 415.3 Revision
1.1 for the determination of TOC and
SUVA (DOC and UV254). This EPA
method contains method performance
data that are not available in the
consensus standards.
Copies of the ASTM standards may be
obtained from the American Society for
Testing and Materials International, 100
Barr Harbor Drive, West Conshohocken,
PA 19428–2959. The Standard Methods
may be obtained from the American
Public Health Association, 1015
Fifteenth Street, NW., Washington, DC
20005.
J. Executive Order 12898: Federal
Actions To Address Environmental
Justice in Minority Populations or LowIncome Populations
Executive Order 12898 establishes a
Federal policy for incorporating
environmental justice into Federal
agency missions by directing agencies to
identify and address disproportionately
high and adverse human health or
environmental effects of its programs,
policies, and activities on minority and
low-income populations. EPA has
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considered environmental justice
related issues concerning the potential
impacts of this action and consulted
with minority and low-income
stakeholders. A description of this
consultation can be found in the
proposed rule (USEPA 2003a).
K. Consultations With the Science
Advisory Board, National Drinking
Water Advisory Council, and the
Secretary of Health and Human Services
In accordance with Section 1412(d)
and (e) of the SDWA, the Agency
consulted with the Science Advisory
Board, the National Drinking Water
Advisory Council (NDWAC), and the
Secretary of Health and Human Services
on today’s rule.
EPA met with the SAB to discuss the
Stage 2 DBPR on June 13, 2001
(Washington, DC), September 25–26,
2001 (teleconference), and December
10–12, 2001 (Los Angeles, CA). Written
comments from the December 2001
meeting of the SAB addressing the
occurrence analysis and risk assessment
were generally supportive. SAB
comments are discussed in greater detail
within the proposal.
EPA met with the NDWAC on
November 8, 2001, in Washington, DC
to discuss the Stage 2 DBPR proposal.
The Advisory Committee generally
supported the need for the Stage 2 DBPR
based on health and occurrence data,
but also stressed the importance of
providing flexibility to the systems
implementing the rule. The results of
these discussions are included in the
docket for the proposed rule.
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L. Plain Language
Executive Order 12866 requires each
agency to write its rules in plain
language. Readable regulations help the
public find requirements quickly and
understand them easily. They increase
compliance, strengthen enforcement,
and decrease mistakes, frustration,
phone calls, appeals, and distrust of
government. EPA made every effort to
write this preamble to the final rule in
as clear, concise, and unambiguous
manner as possible.
M. Analysis of the Likely Effect of
Compliance With the Stage 2 DBPR on
the Technical, Managerial, and
Financial Capacity of Public Water
Systems
Section 1420(d)(3) of SDWA, as
amended, requires that, in promulgating
a National Primary Drinking Water
Regulation (NPDWR), the Administrator
shall include an analysis of the likely
effect of compliance with the regulation
on the technical, managerial, and
financial (TMF) capacity of PWSs. This
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analysis is described in more detail and
can be found in the Economic Analysis
(USEPA 2005a). Analyses reflect only
the impact of new or revised
requirements, as established by the
LT2ESWTR; the impacts of previously
established requirements on system
capacity are not considered.
EPA has defined overall water system
capacity as the ability to plan for,
achieve, and maintain compliance with
applicable drinking water standards.
Capacity encompasses three
components: technical, managerial, and
financial. Technical capacity is the
physical and operational ability of a
water system to meet SDWA
requirements. This refers to the physical
infrastructure of the water system,
including the adequacy of source water
and the adequacy of treatment, storage,
and distribution infrastructure. It also
refers to the ability of system personnel
to adequately operate and maintain the
system and to otherwise implement
requisite technical knowledge.
Managerial capacity is the ability of a
water system to conduct its affairs to
achieve and maintain compliance with
SDWA requirements. Managerial
capacity refers to the system’s
institutional and administrative
capabilities. Financial capacity is a
water system’s ability to acquire and
manage sufficient financial resources to
allow the system to achieve and
maintain compliance with SDWA
requirements.
EPA estimated the impact of the Stage
2 DBPR on small and large system
capacity as a result of the measures that
systems are expected to adopt to meet
the requirements of the rule (e.g.,
selecting monitoring sites for the IDSE,
installing/upgrading treatment, operator
training, communication with regulators
and the service community, etc.). The
Stage 2 DBPR may have a substantial
impact on the capacity of the 1,743
plants in small systems and 518 plants
in large systems that must make changes
to their treatment process to meet the
Stage 2 DBPR requirements. However,
while the impact to these systems is
potentially significant, only 3.8 percent
of all plants regulated under the Stage
2 DBPR (2,261 of 60,220) will be
affected by this requirement. Since
individual systems may employ more
than one plant, it is likely that fewer
than 1,620 systems (3.4 percent of
48,293 systems) will be affected by this
requirement. The new IDSE and
monitoring requirements are expected to
have a small impact on the technical
and managerial capacity of small
systems, a moderate impact on the
financial capacity of some small
systems, and a much smaller impact on
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large systems. The capacity of systems
that must conduct an operational
evaluation will only be impacted in a
minor way, while those systems that
must only familiarize themselves with
the rule (the large majority of systems)
will not face any capacity impact as a
result of the Stage 2 DBPR.
N. Congressional Review Act
The Congressional Review Act, 5
U.S.C. 801 et seq., as added by the Small
Business Regulatory Enforcement
Fairness Act of 1996, generally provides
that before a rule may take effect, the
agency promulgating the rule must
submit a rule report, which includes a
copy of the rule, to each House of the
Congress and to the Comptroller General
of the United States. EPA will submit a
report containing this rule and other
required information to the U.S. Senate,
the U.S. House of Representatives, and
the Comptroller General of the United
States prior to publication of the rule in
the Federal Register. A Major rule
cannot take effect until 60 days after it
is published in the Federal Register.
This action is a ‘‘major rule’’ as defined
by 5 U.S.C. 804(2). This rule will be
effective March 6, 2006.
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safewater/methods/sourcalt.html.)
USEPA. 2005i. Guidelines for carcinogen risk
assessment. Office of Research and
Development, Washington, DC. EPA/
PO 00000
Frm 00090
Fmt 4701
Sfmt 4700
630/P–03/001F. Available online at
https://cfpub.epa.gov/ncea/.
USEPA. 2005j. Supplemental guidance for
assessing susceptibility from early-life
exposure to carcinogens. Office of
Research and Development, Washington,
DC. EPA/630/R–03/003F. Available
online at https://cfpub.epa.gov/ncea/.
USEPA. 2005k. Drinking Water Addendum to
the IRIS Toxicological Review of
Dichloroacetic Acid. Washington, DC.
EPA 822–R–05–009.
USEPA. 2005l. Method 415.3. Determination
of Total Organic Carbon and Specific UV
Absorbance at 254 nm in Source Water
and Drinking Water. Revision 1.1. EPA/
600/R–05/055. (Available at https://
www.epa.gov/nerlcwww/ordmeth.htm.)
USEPA. 2005m. Unregulated Contaminant
Monitoring Regulation (UCMR) for
Public Water Systems Revions; Proposed
Rule. 70 FR 49094, August 22, 2005.
USEPA. 2005n. Information Collection
Request for National Primary Drinking
Water Regulations: Final Stage 2
Disinfectants and Disinfection
Byproducts Rule. Washington, DC. EPA
815–Z–05–002.
USEPA. 2006. Initial Distribution System
Evaluation Guidance Manual for the
Final Stage 2 Disinfectants and
Disinfection Byproducts Rule.
Washington, DC. EPA 815–B–06–002.
USFDA (Food and Drug Administration).
1994. Sanitizing Solutions. 21 Code of
Federal Regulation, Part
178.1010.&https://ecfr.gpoaccess.gov/cgi/
t/text/text-idx?c=ecfr&tpl=%2Findex.tpl
Villanueva, C.M., M. Kogevinas and J.O.
Grimalt. 2001. Drinking water
chlorination and adverse health effects: a
review of epidemiological studies.
Medicina Clinica 117(1): 27–35.
(Spanish).
Villanueva, C.M., Fernandez, F., Malats, N.,
Grimalt, J.O., and Kogenvinas, M. 2003.
Meta-analysis of Studies on Individual
Consumption of Chlorinated Drinking
Water and Bladder Cancer. Journal of
Epidemiology Community Health 57:
166–173.
Villanueva, C.M., K.P. Cantor, S. Cordier,
J.J.K. Jaakkola, W.D. King, C.F. Lynch, S.
Porru and M. Kogevinas. 2004.
Disinfection byproducts and bladder
cancer a pooled analysis. Epidemiology.
15(3):357–367.
Vinceti, M., G. Fantuzzi, L. Monici, et al.
2004. A retrospective cohort study of
trihalomethane exposure through
drinking water and cancer mortality in
northern Italy. Science of the Total
Environment. 330(1–3):47–53.
Vineis, P. 2004. A self-fulfilling prophecy:
are we underestimating the role of the
environment in gene-environment
interaction research? International
Journal of Epidemiology. 33:945–946.
Waller, K., S.H. Swan, G. DeLorenze, B.
Hopkins. 1998. Trihalomethanes in
drinking water and spontaneous
abortion. Epidemiology. 9(2):134–140.
Waller, K., S.H. Swan, G.C. Windham and L.
Fenster. 2001. Influence of exposure
assessment methods on risk estimates in
an epidemiologic study of total
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trihalomethane exposure and
spontaneous abortion. Journal of
Exposure Analysis and Environmental
Epidemiology. 11(6): 522–531.
Weinberg, H.S., S.W. Krasner, S.D.
Richardson and A.D. Thruston, Jr. 2002.
The Occurrence of Disinfection ByProducts (DBPs) of Health Concern in
Drinking Water: Results of a Nationwide
DBP Occurrence Study, U.S.
Environmental Protection Agency,
National Exposure Research Laboratory,
Athens, GA. EPA/600/R–02/068. https://
www.epa.gov/athens/publications/
EPA600R02068.pdf.
WHO. 2000. World Health Organization,
International Programme on Chemical
Safety (IPCS). Environmental Health
Criteria 216: Disinfectants and
Disinfectant By-products.
Windham, GC, Swan SH, Fenster L, Neutra
RR. 1992. Tap or bottled water
consumption and spontaneous abortion:
a 1986 case-control study in California.
Epidemiology. 3:113–9.
Windham GC, Waller K, Anderson M,
Fenster L, Mendola P, and Swan S. 2003.
Chlorination by-products in drinking
water and menstrual cycle function.
Environ Health Perspect: doi:10.1289/
ehp.5922. https://ehpnet1.niehs.nih.gov/
docs/2003/5922/abstract.html.
Wrensch, M., S.H. Swan, J. Lipscomb, D.M.
Epstein, R.R. Neutra, and L. Fenster.
1992. Spontaneous abortions and birth
defects related to tap and bottled water
use, San Jose, California, 1980–1985.
Epidemiology. 3(2):98–103.
Wright, J.M., J. Schwartz and D.W. Dockery.
2003. Effect of trihalomethane exposure
on fetal development. Occupational and
Environmental Medicine. 60(3):173–180.
Wright, J.M., J. Schwartz and D.W. Dockery.
2004. The effect of disinfection byproducts and mutagenic activity on birth
weight and gestational duration.
Environmental Health Perspectives.
112(8):920–925.
Xu, X., T.M. Marino, J.D. Laskin and C.P.
Weisel. 2002. Pericutaneous absorption
of trihalomethanes, haloacetic acids, and
haloketones. Toxicology and Applied
Pharmacology. 184(1):19–26.
Yang, C.Y., Chiu, H.F, Cheng, M.F., and Tsai,
S.S. 1998. Chlorination of Drinking
Water and Cancer Mortality in Taiwan.
Environ Res, 78:1–6.
Yang, V., B. Cheng, S. Tsai, T. Wu, M. Lin
M. and K. Lin. 2000. Association
between chlorination of drinking water
and adverse pregnancy outcome in
Taiwan. Environ. Health. Perspect.
108:765–68.
Yang, C.–Y. 2004. Drinking water
chlorination and adverse birth outcomes
in Taiwan. Toxicology. 198(2004):249–
254.
Zheng, M., S. Andrews, and J. Bolton. 1999.
Impacts of medium-pressure UV on THM
and HAA formation in pre-UV
chlorinated drinking water. Proceedings,
Water Quality Technology Conference of
the American Water Works Association,
Denver, CO.
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List of Subjects
OMB control
No.
40 CFR citation
40 CFR Part 9
*
Reporting and recordkeeping
requirements.
*
*
*
National Primary Drinking Water
Regulations
40 CFR Part 141
Environmental protection, Chemicals,
Indians-lands, Incorporation by
reference, Intergovernmental relations,
Radiation protection, Reporting and
recordkeeping requirements, Water
supply.
*
*
*
*
141.600–141.605 ..................
141.620–141.626 ..................
141.629 .................................
*
*
2040–0265
2040–0265
2040–0265
National Primary Drinking Water
Regulations Implementation
40 CFR Part 142
Environmental protection,
Administrative practice and procedure,
Chemicals, Indians-lands, Radiation
protection, Reporting and recordkeeping
requirements, Water supply.
*
*
*
142.14(a)(1)–(7) ....................
142.14(a)(8) ..........................
142.14(b)–(d) ........................
*
*
2040–0265
2040–0265
2040–0090
Dated: December 15, 2005.
Stephen L. Johnson,
Administrator.
*
*
*
142.16(m) .............................
*
*
2040–0265
For the reasons set forth in the
preamble, title 40 chapter I of the Code
of Federal Regulations is amended as
follows:
I
PART 9—OMB APPROVALS UNDER
THE PAPERWORK REDUCTION ACT
1. The authority citation for part 9
continues to read as follows:
I
Authority: 7 U.S.C. 135 et seq., 136–136y;
15 U.S.C. 2001, 2003, 2005, 2006, 2601–2671;
21 U.S.C. 331j, 346a, 348; 31 U.S.C. 9701; 33
U.S.C. 1251 et seq., 1311, 1313d, 1314, 1318,
1321, 1326, 1330, 1342, 1344, 1345 (d) and
(e), 1361; Executive Order 11735, 38 FR
21243, 3 CFR, 1971–1975 Comp. p. 973; 42
U.S.C. 241, 242b, 243, 246, 300f, 300g, 300g–
1, 300g–2, 300g–3, 300g–4, 300g–5, 300g–6,
300j–1, 300j–2, 300j–3, 300j–4, 300j–9, 1857
et seq., 6901–6992k, 7401–7671q, 7542,
9601–9657, 11023, 11048.
2. In § 9.1 the table is amended as
follows:
I a. Under the heading ‘‘National
Primary Drinking Water Regulations
Implementation’’ by adding entries in
numerical order for ‘‘§ 141.600–141.605,
141.620–141.626, 141.629’’.
I b. Under the heading ‘‘National
Primary Drinking Water Regulations
Implementation’’ by removing entries
‘‘§ 142.14(a),142.14(a)–(d)(3)’’ and
adding entries in numerical order for
‘‘142.14(a) (1)–(7), 142.14(a)(8),
142.14(b)–(d) and 142.16(m)’’ as
follows:
I
§ 9.1 OMB approvals under the Paperwork
Reduction Act.
*
PO 00000
*
*
*
*
OMB control
No.
40 CFR citation
Frm 00091
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*
*
*
*
*
PART 141—NATIONAL PRIMARY
DRINKING WATER REGULATIONS
3. The authority citation for part 141
continues to read as follows:
I
Authority: 42 U.S.C. 300f, 300g–1, 300g–2,
300g–3, 300g–4, 300g–5, 300g–6, 300j–4,
300j–9, and 300j–11.
4. Section 141.2 is amended by
adding, in alphabetical order,
definitions for ‘‘Combined distribution
system’’, ‘‘Consecutive system’’, ‘‘Dual
sample sets’’, ‘‘Finished water’’,
‘‘GAC20’’, ‘‘Locational running annual
average’’, and ‘‘Wholesale system’’ and
revising the definition of ‘‘GAC10’’ to
read as follows:
I
§ 141.2
Definitions.
*
*
*
*
*
Combined distribution system is the
interconnected distribution system
consisting of the distribution systems of
wholesale systems and of the
consecutive systems that receive
finished water.
*
*
*
*
*
Consecutive system is a public water
system that receives some or all of its
finished water from one or more
wholesale systems. Delivery may be
through a direct connection or through
the distribution system of one or more
consecutive systems.
*
*
*
*
*
Dual sample set is a set of two
samples collected at the same time and
same location, with one sample
analyzed for TTHM and the other
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sample analyzed for HAA5. Dual sample
sets are collected for the purposes of
conducting an IDSE under subpart U of
this part and determining compliance
with the TTHM and HAA5 MCLs under
subpart V of this part.
*
*
*
*
*
Finished water is water that is
introduced into the distribution system
of a public water system and is intended
for distribution and consumption
without further treatment, except as
treatment necessary to maintain water
quality in the distribution system (e.g.,
booster disinfection, addition of
corrosion control chemicals).
*
*
*
*
*
GAC10 means granular activated
carbon filter beds with an empty-bed
contact time of 10 minutes based on
average daily flow and a carbon
reactivation frequency of every 180
days, except that the reactivation
frequency for GAC10 used as a best
available technology for compliance
with subpart V MCLs under
§ 141.64(b)(2) shall be 120 days.
GAC20 means granular activated
carbon filter beds with an empty-bed
contact time of 20 minutes based on
average daily flow and a carbon
reactivation frequency of every 240
days.
*
*
*
*
*
Locational running annual average
(LRAA) is the average of sample
analytical results for samples taken at a
particular monitoring location during
the previous four calendar quarters.
*
*
*
*
*
Wholesale system is a public water
system that treats source water as
necessary to produce finished water and
then delivers some or all of that finished
water to another public water system.
Delivery may be through a direct
connection or through the distribution
system of one or more consecutive
systems.
§ 141.12
[Removed]
5. Section 141.12 is removed and
reserved.
I
§ 141.30
I
[Removed]
6. Section 141.30 is removed.
§ 141.32
[Removed]
7. Section 141.32 is removed and
reserved.
I 8. Section 141.33 is amended by
revising the first sentence of paragraph
(a) introductory text and adding
paragraph (f) to read as follows:
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I
§ 141.33
Record maintenance.
*
*
*
*
*
(a) Records of microbiological
analyses and turbidity analyses made
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20:53 Jan 03, 2006
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pursuant to this part shall be kept for
not less than 5 years. * * *
*
*
*
*
*
(f) Copies of monitoring plans
developed pursuant to this part shall be
kept for the same period of time as the
records of analyses taken under the plan
are required to be kept under paragraph
(a) of this section, except as specified
elsewhere in this part.
9. Section 141.53 is amended by
revising the table to read as follows:
I
§ 141.53 Maximum contaminant level goals
for disinfection byproducts.
*
*
*
*
*
Disinfection byproduct
Bromodichloromethane .........
Bromoform ............................
Bromate .................................
Chlorite ..................................
Chloroform ............................
Dibromochloromethane .........
Dichloroacetic acid ................
Monochloroacetic acid ..........
Trichloroacetic acid ...............
MCLG (mg/L)
zero
zero
zero
0.8
0.07
0.06
zero
0.07
0.02
§ 141.64 Maximum contaminant levels for
disinfection byproducts.
(a) Bromate and chlorite. The
maximum contaminant levels (MCLs)
for bromate and chlorite are as follows:
MCL (mg/L)
0.010
1.0
(1) Compliance dates for CWSs and
NTNCWSs. Subpart H systems serving
10,000 or more persons must comply
with this paragraph (a) beginning
January 1, 2002. Subpart H systems
serving fewer than 10,000 persons and
systems using only ground water not
under the direct influence of surface
water must comply with this paragraph
(a) beginning January 1, 2004.
(2) The Administrator, pursuant to
section 1412 of the Act, hereby
identifies the following as the best
technology, treatment techniques, or
other means available for achieving
compliance with the maximum
contaminant levels for bromate and
chlorite identified in this paragraph (a):
Disinfection byproduct
Bromate
PO 00000
Best available technology
Control of ozone treatment process to reduce production of bromate
Frm 00092
Fmt 4701
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Control of treatment processes to
reduce disinfectant demand and
control of disinfection treatment
processes to reduce disinfectant
levels
(b) TTHM and HAA5. (1) Subpart L—
RAA compliance. (i) Compliance dates.
Subpart H systems serving 10,000 or
more persons must comply with this
paragraph (b)(1) beginning January 1,
2002. Subpart H systems serving fewer
than 10,000 persons and systems using
only ground water not under the direct
influence of surface water must comply
with this paragraph (b)(1) beginning
January 1, 2004. All systems must
comply with these MCLs until the date
specified for subpart V compliance in
§ 141.620(c).
Total trihalomethanes (TTHM)
Haloacetic acids (five) (HAA5)
10. Section 141.64 is revised to read
as follows:
Bromate ....................................
Chlorite .....................................
Chlorite
Best available technology
Disinfection byproduct
I
Disinfection byproduct
Disinfection byproduct
MCL (mg/L)
0.080
0.060
(ii) The Administrator, pursuant to
section 1412 of the Act, hereby
identifies the following as the best
technology, treatment techniques, or
other means available for achieving
compliance with the maximum
contaminant levels for TTHM and
HAA5 identified in this paragraph
(b)(1):
Disinfection byproduct
Best available technology
Total trihalomethanes
(TTHM) and
Haloacetic acids
(five) (HAA5).
Enhanced coagulation or enhanced
softening or
GAC10, with chlorine as the primary
and residual disinfectant
(2) Subpart V—LRAA compliance. (i)
Compliance dates. The subpart V MCLs
for TTHM and HAA5 must be complied
with as a locational running annual
average at each monitoring location
beginning the date specified for subpart
V compliance in § 141.620(c).
Disinfection byproduct
Total trihalomethanes (TTHM)
Haloacetic acids (five) (HAA5)
MCL (mg/L)
0.080
0.060
(ii) The Administrator, pursuant to
section 1412 of the Act, hereby
identifies the following as the best
technology, treatment techniques, or
other means available for achieving
compliance with the maximum
contaminant levels for TTHM and
HAA5 identified in this paragraph (b)(2)
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for all systems that disinfect their source
water:
Disinfection byproduct
Best available technology
Total
trihalomethanes (TTHM)
and
Haloacetic
acids (five)
(HAA5).
Enhanced coagulation or enhanced softening, plus
GAC10; or nanofiltration
with a molecular weight
cutoff ≤1000 Daltons; or
GAC20
(iii) The Administrator, pursuant to
section 1412 of the Act, hereby
identifies the following as the best
technology, treatment techniques, or
other means available for achieving
compliance with the maximum
contaminant levels for TTHM and
HAA5 identified in this paragraph (b)(2)
for consecutive systems and applies
only to the disinfected water that
consecutive systems buy or otherwise
receive:
Disinfection byproduct
Best available technology
Total
trihalomethanes (TTHM)
and
Haloacetic
acids (five)
(HAA5).
Systems serving ≥10,000:
Improved distribution system and storage tank
management to reduce
residence time, plus the
use of chloramines for disinfectant residual maintenance
Systems serving <10,000:
Improved distribution system and storage tank
management to reduce
residence time
11. Section 141.131 is amended as
follows:
I a. By revising paragraph (a),
I b. By revising paragraphs (b)(1) and
(b)(2),
I c. By revising the table in paragraph
(c)(1),
I d. By revising paragraphs (d)(2),
(d)(3), (d)(4)(i), and (d)(4)(ii),
I e. By adding paragraph (d)(6).
I
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§ 141.131
Analytical requirements.
(a) General. (1) Systems must use only
the analytical methods specified in this
section, or their equivalent as approved
by EPA, to demonstrate compliance
with the requirements of this subpart
and with the requirements of subparts U
and V of this part. These methods are
effective for compliance monitoring
February 16, 1999, unless a different
effective date is specified in this section
or by the State.
(2) The following documents are
incorporated by reference. The Director
of the Federal Register approves this
incorporation by reference in
accordance with 5 U.S.C. 552(a) and 1
VerDate Aug<31>2005
20:53 Jan 03, 2006
Jkt 208001
CFR part 51. Copies may be inspected
at EPA’s Drinking Water Docket, 1301
Constitution Avenue, NW., EPA West,
Room B102, Washington, DC 20460, or
at the National Archives and Records
Administration (NARA). For
information on the availability of this
material at NARA, call 202–741–6030,
or go to: https://www.archives.gov/
federal_register/
code_of_federal_regulations/
ibr_locations.html. EPA Method 552.1 is
in Methods for the Determination of
Organic Compounds in Drinking WaterSupplement II, USEPA, August 1992,
EPA/600/R–92/129 (available through
National Information Technical Service
(NTIS), PB92–207703). EPA Methods
502.2, 524.2, 551.1, and 552.2 are in
Methods for the Determination of
Organic Compounds in Drinking WaterSupplement III, USEPA, August 1995,
EPA/600/R–95/131 (available through
NTIS, PB95–261616). EPA Method
300.0 is in Methods for the
Determination of Inorganic Substances
in Environmental Samples, USEPA,
August 1993, EPA/600/R–93/100
(available through NTIS, PB94–121811).
EPA Methods 300.1 and 321.8 are in
Methods for the Determination of
Organic and Inorganic Compounds in
Drinking Water, Volume 1, USEPA,
August 2000, EPA 815–R–00–014
(available through NTIS, PB2000–
106981). EPA Method 317.0, Revision
2.0, ‘‘Determination of Inorganic
Oxyhalide Disinfection By-Products in
Drinking Water Using Ion
Chromatography with the Addition of a
Postcolumn Reagent for Trace Bromate
Analysis,’’ USEPA, July 2001, EPA 815–
B–01–001, EPA Method 326.0, Revision
1.0, ‘‘Determination of Inorganic
Oxyhalide Disinfection By-Products in
Drinking Water Using Ion
Chromatography Incorporating the
Addition of a Suppressor Acidified
Postcolumn Reagent for Trace Bromate
Analysis,’’ USEPA, June 2002, EPA 815–
R–03–007, EPA Method 327.0, Revision
1.1, ‘‘Determination of Chlorine Dioxide
and Chlorite Ion in Drinking Water
Using Lissamine Green B and
Horseradish Peroxidase with Detection
by Visible Spectrophotometry,’’ USEPA,
May 2005, EPA 815–R–05–008 and EPA
Method 552.3, Revision 1.0,
‘‘Determination of Haloacetic Acids and
Dalapon in Drinking Water by Liquidliquid Microextraction, Derivatization,
and Gas Chromatography with Electron
Capture Detection,’’ USEPA, July 2003,
EPA–815–B–03–002 can be accessed
and downloaded directly on-line at
https://www.epa.gov/safewater/methods/
sourcalt.html. EPA Method 415.3,
Revision 1.1, ‘‘Determination of Total
PO 00000
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Fmt 4701
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479
Organic Carbon and Specific UV
Absorbance at 254 nm in Source Water
and Drinking Water,’’ USEPA, February
2005, EPA/600/R–05/055 can be
accessed and downloaded directly online at www.epa.gov/nerlcwww/
ordmeth.htm. Standard Methods 4500–
Cl D, 4500–Cl E, 4500–Cl F, 4500–Cl G,
4500–Cl H, 4500–Cl I, 4500–ClO2 D,
4500–ClO2 E, 6251 B, and 5910 B shall
be followed in accordance with
Standard Methods for the Examination
of Water and Wastewater, 19th or 20th
Editions, American Public Health
Association, 1995 and 1998,
respectively. The cited methods
published in either edition may be used.
Standard Methods 5310 B, 5310 C, and
5310 D shall be followed in accordance
with the Supplement to the 19th Edition
of Standard Methods for the
Examination of Water and Wastewater,
or the Standard Methods for the
Examination of Water and Wastewater,
20th Edition, American Public Health
Association, 1996 and 1998,
respectively. The cited methods
published in either edition may be used.
Copies may be obtained from the
American Public Health Association,
1015 Fifteenth Street, NW., Washington,
DC 20005. Standard Methods 4500–Cl
D–00, 4500–Cl E–00, 4500–Cl F–00,
4500–Cl G–00, 4500–Cl H–00, 4500–Cl
I–00, 4500–ClO2 E–00, 6251 B–94, 5310
B–00, 5310 C–00, 5310 D–00 and 5910
B–00 are available at https://
www.standardmethods.org or at EPA’s
Water Docket. The year in which each
method was approved by the Standard
Methods Committee is designated by the
last two digits in the method number.
The methods listed are the only Online
versions that are IBR-approved. ASTM
Methods D 1253–86 and D 1253–86
(Reapproved 1996) shall be followed in
accordance with the Annual Book of
ASTM Standards, Volume 11.01,
American Society for Testing and
Materials International, 1996 or any
ASTM edition containing the IBRapproved version of the method may be
used. ASTM Method D1253–03 shall be
followed in accordance with the Annual
Book of ASTM Standards, Volume
11.01, American Society for Testing and
Materials International, 2004 or any
ASTM edition containing the IBRapproved version of the method may be
used. ASTM Method D 6581–00 shall be
followed in accordance with the Annual
Book of ASTM Standards, Volume
11.01, American Society for Testing and
Materials International, 2001 or any
ASTM edition containing the IBRapproved version of the method may be
used; copies may be obtained from the
American Society for Testing and
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Materials International, 100 Barr Harbor
Drive, West Conshohocken, PA 19428–
2959.
(b) Disinfection byproducts. (1)
Systems must measure disinfection
byproducts by the methods (as modified
by the footnotes) listed in the following
table:
APPROVED METHODS FOR DISINFECTION BYPRODUCT COMPLIANCE MONITORING
Contaminant and methodology 1
EPA method
TTHM
P&T/GC/ElCD & PID ...................................
P&T/GC/MS ................................................
LLE/GC/ECD ...............................................
HAA5
LLE (diazomethane)/GC/ECD .....................
SPE (acidic methanol)/GC/ECD .................
LLE (acidic methanol)/GC/ECD ..................
Bromate
Ion chromatography ....................................
Ion chromatography & post column reaction.
IC/ICP–MS ..................................................
Chlorite
Amperometric titration .................................
Spectrophotometry ......................................
Ion chromatography ....................................
Standard method 2
SM online 9
502.2 4 ..........................
524.2 ............................
551.1 ............................
......................................
......................................
......................................
......................................
......................................
......................................
......................................
552.1 5 ..........................
552.2, 552.3 .................
6251 B 5 .......................
......................................
......................................
6251 B–94 ...................
......................................
......................................
300.1 ............................
317.0 Rev 2.0 6, 326.0 6
......................................
......................................
......................................
......................................
321.86 7 ........................
......................................
......................................
......................................
327.0 Rev 1.1 8 ............
300.0, 300.1, 317.0
Rev 2.0, 326.0.
4500–ClO2 E 8 .............
......................................
......................................
4500–ClO2 E–00 8 .......
......................................
......................................
ASTM method 3
D 6581–00
D 6581–00
1 P&T = purge and trap; GC = gas chromatography; ElCD = electrolytic conductivity detector; PID = photoionization detector; MS = mass spectrometer; LLE = liquid/liquid extraction; ECD = electron capture detector; SPE = solid phase extraction; IC = ion chromatography; ICP–MS = inductively coupled plasma/mass spectrometer.
2 19th and 20th editions of Standard Methods for the Examination of Water and Wastewater, 1995 and 1998, respectively, American Public
Health Association; either of these editions may be used.
3 Annual Book of ASTM Standards, 2001 or any year containing the cited version of the method, Vol 11.01.
4 If TTHMs are the only analytes being measured in the sample, then a PID is not required.
5 The samples must be extracted within 14 days of sample collection.
6 Ion chromatography & post column reaction or IC/ICP-MS must be used for monitoring of bromate for purposes of demonstrating eligibility of
reduced monitoring, as prescribed in § 141.132(b)(3)(ii).
7 Samples must be preserved at the time of sampling with 50 mg ethylenediamine (EDA)/L of sample and must be analyzed within 28 days.
8 Amperometric titration or spectrophotometry may be used for routine daily monitoring of chlorite at the entrance to the distribution system, as
prescribed in § 141.132(b)(2)(i)(A). Ion chromatography must be used for routine monthly monitoring of chlorite and additional monitoring of chlorite in the distribution system, as prescribed in § 141.132(b)(2)(i)(B) and (b)(2)(ii).
9 The Standard Methods Online version that is approved is indicated by the last two digits in the method number which is the year of approval
by the Standard Method Committee. Standard Methods Online are available at https://www.standardmethods.org.
(2) Analyses under this section for
disinfection byproducts must be
conducted by laboratories that have
received certification by EPA or the
State, except as specified under
paragraph (b)(3) of this section. To
receive certification to conduct analyses
for the DBP contaminants in §§ 141.64,
141.135, and subparts U and V of this
part, the laboratory must:
(i) Analyze Performance Evaluation
(PE) samples that are acceptable to EPA
or the State at least once during each
consecutive 12 month period by each
method for which the laboratory desires
certification.
(ii) Until March 31, 2007, in these
analyses of PE samples, the laboratory
must achieve quantitative results within
the acceptance limit on a minimum of
80% of the analytes included in each PE
Acceptance
limits (percent
of true value)
DBP
TTHM
Chloroform ...........................................................................
±20
Bromodichloromethane .......................................................
Dibromochloromethane .......................................................
Bromoform ...........................................................................
HAA5
Monochloroacetic Acid ........................................................
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sample. The acceptance limit is defined
as the 95% confidence interval
calculated around the mean of the PE
study between a maximum and
minimum acceptance limit of +/¥50%
and +/¥15% of the study mean.
(iii) Beginning April 1, 2007, the
laboratory must achieve quantitative
results on the PE sample analyses that
are within the following acceptance
limits:
Laboratory must meet all 4 individual THM acceptance limits
in order to successfully pass a PE sample for TTHM
±20
±20
±20
Dichloroacetic Acid ..............................................................
Trichloroacetic Acid .............................................................
Monobromoacetic Acid ........................................................
Dibromoacetic Acid .............................................................
Chlorite .......................................................................................
Comments
±40
±40
±40
±40
±30
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Laboratory must meet the acceptance limits for 4 out of 5 of
the HAA5 compounds in order to successfully pass a PE
sample for HAA5
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Acceptance
limits (percent
of true value)
DBP
Comments
±30
Bromate ......................................................................................
(iv) Beginning April 1, 2007, report
quantitative data for concentrations at
least as low as the ones listed in the
481
following table for all DBP samples
analyzed for compliance with §§ 141.64,
141.135, and subparts U and V of this
part:
Minimum reporting level
(mg/L) 1
DBP
TTHM 2
Chloroform .............................................................................
Bromodichloromethane ..........................................................
Dibromochloromethane .........................................................
Bromoform .............................................................................
HAA5 2
Monochloroacetic Acid ..........................................................
Dichloroacetic Acid ................................................................
Trichloroacetic Acid ...............................................................
Monobromoacetic Acid ..........................................................
Dibromoacetic Acid ................................................................
Chlorite ..........................................................................................
Bromate ........................................................................................
Comments
0.0010
0.0010
0.0010
0.0010
0.0020
0.0010
0.0010
0.0010
0.0010
0.020
0.0050 or
0.0010
Applicable to monitoring as prescribed in § 141.132(b)(2)(1)(B)
and (b)(2)(ii).
Laboratories that use EPA Methods 317.0 Revision 2.0, 326.0
or 321.8 must meet a 0.0010 mg/L MRL for bromate.
1 The calibration curve must encompass the regulatory minimum reporting level (MRL) concentration. Data may be reported for concentrations
lower than the regulatory MRL as long as the precision and accuracy criteria are met by analyzing an MRL check standard at the lowest reporting limit chosen by the laboratory. The laboratory must verify the accuracy of the calibration curve at the MRL concentration by analyzing an
MRL check standard with a concentration less than or equal to 110% of the MRL with each batch of samples. The measured concentration for
the MRL check standard must be ±50% of the expected value, if any field sample in the batch has a concentration less than 5 times the regulatory MRL. Method requirements to analyze higher concentration check standards and meet tighter acceptance criteria for them must be met in
addition to the MRL check standard requirement.
2 When adding the individual trihalomethane or haloacetic acid concentrations to calculate the TTHM or HAA5 concentrations, respectively, a
zero is used for any analytical result that is less than the MRL concentration for that DBP, unless otherwise specified by the State.
*
*
*
(c) * * *
*
*
(1) * * *
Residual measured 1
SM (19th or
20th ed)
Methodology
Amperometric Titration
4500–C D
Low Level Amperometric Titration.
DPD Ferrous Titrimetric
4500–C E
DPD Colorimetric ..........
4500–C G
Syringaldazine (FACTS)
4500–C H
Iodometric Electrode ....
DPD ..............................
Amperometric Method II
4500–C I
4500–C O2 D
4500–C O2 E
4500–C F
SM
Online 2
4500–C
00
4500–C
00
4500–C
00
4500–C
00
4500–C
00
4500–C
ASTM
method
D–
Free
Cl2
Combined
Cl2
Total
Cl2
X
D 1253–86 (96),
03
X
X
E–
ClO2
X
F–
X
X
X
G–
X
X
X
H–
X
I–00
X
X
X
4500–C O2
E–00
Lissamine Green
Spectrophotometric.
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EPA
method
327.0 Rev
1.1
X
1 X indicates method is approved for measuring specified disinfectant residual. Free chlorine or total chlorine may be measured for demonstrating compliance with the chlorine MRDL and combined chlorine, or total chlorine may be measured for demonstrating compliance with the
chloramine MRDL.
2 The Standard Methods Online version that is approved is indicated by the last two digits in the method number which is the year of approval
by the Standard Method Committee. Standard Methods Online are available at https://www.standardmethods.org.
*
*
*
(d) * * *
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*
*
20:53 Jan 03, 2006
(2) Bromide. EPA Methods 300.0,
300.1, 317.0 Revision 2.0, 326.0, or
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(3) Total Organic Carbon (TOC).
Standard Method 5310 B or 5310 B–00
(High-Temperature Combustion
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Method) or Standard Method 5310 C or
5310 C–00 (Persulfate-Ultraviolet or
Heated-Persulfate Oxidation Method) or
Standard Method 5310 D or 5310 D–00
(Wet-Oxidation Method) or EPA Method
415.3 Revision 1.1. Inorganic carbon
must be removed from the samples prior
to analysis. TOC samples may not be
filtered prior to analysis. TOC samples
must be acidified at the time of sample
collection to achieve pH less than or
equal to 2 with minimal addition of the
acid specified in the method or by the
instrument manufacturer. Acidified
TOC samples must be analyzed within
28 days.
(4) * * *
(i) Dissolved Organic Carbon (DOC).
Standard Method 5310 B or 5310 B–00
(High-Temperature Combustion
Method) or Standard Method 5310 C or
5310 C–00 (Persulfate-Ultraviolet or
Heated-Persulfate Oxidation Method) or
Standard Method 5310 D or 5310 D–00
(Wet-Oxidation Method) or EPA Method
415.3 Revision 1.1. DOC samples must
be filtered through the 0.45 µm porediameter filter as soon as practical after
sampling, not to exceed 48 hours. After
filtration, DOC samples must be
acidified to achieve pH less than or
equal to 2 with minimal addition of the
acid specified in the method or by the
instrument manufacturer. Acidified
DOC samples must be analyzed within
28 days of sample collection. Inorganic
carbon must be removed from the
samples prior to analysis. Water passed
through the filter prior to filtration of
the sample must serve as the filtered
blank. This filtered blank must be
analyzed using procedures identical to
those used for analysis of the samples
and must meet the following criteria:
DOC < 0.5 mg/L.
(ii) Ultraviolet Absorption at 254 nm
(UV254). Standard Method 5910 B or
5910 B–00 (Ultraviolet Absorption
Method) or EPA Method 415.3 Revision
1.1. UV absorption must be measured at
253.7 nm (may be rounded off to 254
nm). Prior to analysis, UV254 samples
must be filtered through a 0.45 µm porediameter filter. The pH of UV254 samples
may not be adjusted. Samples must be
analyzed as soon as practical after
sampling, not to exceed 48 hours.
*
*
*
*
*
(6) Magnesium. All methods allowed
in § 141.23(k)(1) for measuring
magnesium.
I 12. Section 141.132 is amended by:
I a. Redesignating paragraphs (b)(1)(iii)
through (b)(1)(v) as paragraphs (b)(1)(iv)
through (b)(1)(vi);
I b. Adding a new paragraph (b)(1)(iii);
I c. Revising newly redesignated
paragraph (b)(1)(iv); and
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21:46 Jan 03, 2006
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d. Revising paragraph (b)(3)(ii).
The addition and revisions read as
follows:
I
§ 141.132
Monitoring requirements.
*
*
*
*
*
(b) * * *
(1) * * *
(iii) Monitoring requirements for
source water TOC. In order to qualify for
reduced monitoring for TTHM and
HAA5 under paragraph (b)(1)(ii) of this
section, subpart H systems not
monitoring under the provisions of
paragraph (d) of this section must take
monthly TOC samples every 30 days at
a location prior to any treatment,
beginning April 1, 2008 or earlier, if
specified by the State. In addition to
meeting other criteria for reduced
monitoring in paragraph (b)(1)(ii) of this
section, the source water TOC running
annual average must be ≤4.0 mg/L
(based on the most recent four quarters
of monitoring) on a continuing basis at
each treatment plant to reduce or
remain on reduced monitoring for
TTHM and HAA5. Once qualified for
reduced monitoring for TTHM and
HAA5 under paragraph (b)(1)(ii) of this
section, a system may reduce source
water TOC monitoring to quarterly TOC
samples taken every 90 days at a
location prior to any treatment.
(iv) Systems on a reduced monitoring
schedule may remain on that reduced
schedule as long as the average of all
samples taken in the year (for systems
which must monitor quarterly) or the
result of the sample (for systems which
must monitor no more frequently than
annually) is no more than 0.060 mg/L
and 0.045 mg/L for TTHMs and HAA5,
respectively. Systems that do not meet
these levels must resume monitoring at
the frequency identified in paragraph
(b)(1)(i) of this section (minimum
monitoring frequency column) in the
quarter immediately following the
monitoring period in which the system
exceeds 0.060 mg/L or 0.045 mg/L for
TTHMs and HAA5, respectively. For
systems using only ground water not
under the direct influence of surface
water and serving fewer than 10,000
persons, if either the TTHM annual
average is >0.080 mg/L or the HAA5
annual average is >0.060 mg/L, the
system must go to the increased
monitoring identified in paragraph
(b)(1)(i) of this section (sample location
column) in the quarter immediately
following the monitoring period in
which the system exceeds 0.080 mg/L or
0.060 mg/L for TTHMs or HAA5
respectively.
*
*
*
*
*
(3) ***
(i) ***
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(ii) Reduced monitoring.
(A) Until March 31, 2009, systems
required to analyze for bromate may
reduce monitoring from monthly to
quarterly, if the system’s average source
water bromide concentration is less than
0.05 mg/L based on representative
monthly bromide measurements for one
year. The system may remain on
reduced bromate monitoring until the
running annual average source water
bromide concentration, computed
quarterly, is equal to or greater than 0.05
mg/L based on representative monthly
measurements. If the running annual
average source water bromide
concentration is ≥0.05 mg/L, the system
must resume routine monitoring
required by paragraph (b)(3)(i) of this
section in the following month.
(B) Beginning April 1, 2009, systems
may no longer use the provisions of
paragraph (b)(3)(ii)(A) of this section to
qualify for reduced monitoring. A
system required to analyze for bromate
may reduce monitoring from monthly to
quarterly, if the system’s running annual
average bromate concentration is
≤0.0025 mg/L based on monthly
bromate measurements under paragraph
(b)(3)(i) of this section for the most
recent four quarters, with samples
analyzed using Method 317.0 Revision
2.0, 326.0 or 321.8. If a system has
qualified for reduced bromate
monitoring under paragraph (b)(3)(ii)(A)
of this section, that system may remain
on reduced monitoring as long as the
running annual average of quarterly
bromate samples ≤0.0025 mg/L based on
samples analyzed using Method 317.0
Revision 2.0, 326.0, or 321.8. If the
running annual average bromate
concentration is >0.0025 mg/L, the
system must resume routine monitoring
required by paragraph (b)(3)(i) of this
section.
*
*
*
*
*
§ 141.133
[Amended]
13. Section 141.133 is amended in the
last sentence of paragraph (d) by
revising the reference ‘‘§ 141.32’’ to read
‘‘subpart Q of this part’’.
I 14. Section 141.135 is amended by
revising paragraph (a)(3)(ii) to read as
follows:
I
§ 141.135 Treatment technique for control
of disinfection byproduct (DBP) precursors.
(a) * * *
(3) * * *
(ii) Softening that results in removing
at least 10 mg/L of magnesium hardness
(as CaCO3), measured monthly
according to § 141.131(d)(6) and
calculated quarterly as a running annual
average.
*
*
*
*
*
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Federal Register / Vol. 71, No. 2 / Wednesday, January 4, 2006 / Rules and Regulations
15. Section 141.151 is amended by
revising paragraph (d) to read as
follows:
I
§ 141.151
subpart.
Purpose and applicability of this
*
*
*
*
*
(d) For the purpose of this subpart,
detected means: at or above the levels
prescribed by § 141.23(a)(4) for
inorganic contaminants, at or above the
levels prescribed by § 141.24(f)(7) for
the contaminants listed in § 141.61(a), at
or above the levels prescribed by
§ 141.24(h)(18) for the contaminants
listed in § 141.61(c), at or above the
levels prescribed by § 141.131(b)(2)(iv)
for the contaminants or contaminant
groups listed in § 141.64, and at or
above the levels prescribed by
§ 141.25(c) for radioactive contaminants.
*
*
*
*
*
I 16. Section 141.153 is amended by
revising paragraphs (d)(4)(iv)(B) and
(d)(4)(iv)(C) to read as follows:
§ 141.153
Content of the reports.
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*
*
*
*
*
(d) * * *
(4) * * *
(iv) * * *
(B) When compliance with the MCL is
determined by calculating a running
annual average of all samples taken at
a monitoring location: the highest
average of any of the monitoring
locations and the range of all monitoring
locations expressed in the same units as
the MCL. For the MCLs for TTHM and
HAA5 in § 141.64(b)(2), systems must
include the highest locational running
annual average for TTHM and HAA5
and the range of individual sample
results for all monitoring locations
expressed in the same units as the MCL.
If more than one location exceeds the
TTHM or HAA5 MCL, the system must
include the locational running annual
averages for all locations that exceed the
MCL.
(C) When compliance with the MCL is
determined on a system-wide basis by
calculating a running annual average of
all samples at all monitoring locations:
the average and range of detection
expressed in the same units as the MCL.
The system is required to include
individual sample results for the IDSE
conducted under subpart U of this part
when determining the range of TTHM
and HAA5 results to be reported in the
annual consumer confidence report for
the calendar year that the IDSE samples
were taken.
*
*
*
*
*
Appendix A to Subpart Q [Amended]
17. In Subpart Q, Appendix A is
amended as follows:
I
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a. In entry I.B.2. in the fifth column,
remove the endnote citation ‘‘9’’ and
add in its place ‘‘11’’;
I b. In entry I.B.11. in the fourth
column, remove the endnote citation
‘‘10’’ and add in its place ‘‘12’’;
I c. In entry I.B.12. in the fourth
column, remove the endnote citation
‘‘10’’ and add in its place ‘‘12’’;
I d. In entry I.G. in the first column,
remove the endnote citation ‘‘11’’ and
add in its place ‘‘13’’;
I e. In entry I.G.1. in the third column,
remove the endnote citation ‘‘12’’ and
add in its place ‘‘14’’ and remove the
citation in the third column ‘‘141.12,
141.64(a)’’ and in its place add
‘‘141.64(b)’’ (keeping the endnote
citation to endnote 14) and in the fifth
column remove the citation ‘‘141.30’’
and add in numerical order the citations
‘‘141.600–141.605, 141.620–141.629’’;
I f. In entry I.G.2. revise the entry
‘‘141.64(a)’’ to read ‘‘141.64(b)’’ and in
the fifth column add in numerical order
the citations ‘‘141.600–141.605,
141.620–141.629’’.
I g. In entry I.G.7. in the fourth column,
remove the endnote citation ‘‘13’’ and
add in its place ‘‘15’’;
I h. In entry I.G.8. in the second
column, remove the endnote citation
‘‘14’’ and add in its place ‘‘16’’;
I i. In entry II. in the first column,
remove the endnote citation ‘‘15’’ and
add in its place ‘‘17’’;
I j. In entry III.A. in the third column,
remove the endnote citation ‘‘16’’ and
add in its place ‘‘18’’;
I k. In entry III.B in the third column,
remove the endnote citation ‘‘17’’ and
add in its place ‘‘19’’;
I l. In entry IV.E. in the first column,
remove the endnote citation ‘‘18’’ and
add in its place 20’’; and
I m. In entry III.F in the second column,
remove the endnote citation ‘‘19’’ and
add in its place ‘‘21’’.
I 18. In Subpart Q, Appendix A, remove
endnote 14 and add in its place, to read
as follows: ‘‘14.§§ 141.64(b)(1)
141.132(a)–(b) apply until §§ 141.620–
141.630 take effect under the schedule
in § 141.620(c).
I 19–20. In Subpart Q, Appendix B is
amended as follows:
I a. In entry G.77. in the third column,
remove the endnote citation ‘‘16’’ and
add in its place ‘‘17’’;
I b. In entry H. (the title) in the first
column, remove the endnote citation
‘‘17’’ and add in its place ‘‘18’’;
I c. In entry H.80. in the third column,
remove the endnote citations ‘‘17, 18’’
and add in its place ‘‘19, 20’’ and
remove the number ‘‘0.10/’’;
I d. In entry H.81. in the third column,
remove the endnote citation ‘‘20’’ and
add in its place ‘‘21’’; and
I
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483
e. In entry H.84. in the second
column, remove the endnote citation
‘‘21’’ and add in its place ‘‘22’’ and in
the third column remove the endnote
citation ‘‘22’’ and add in its place ‘‘23’’.
I f. Revise endnotes 18 and 19.
The revisions read as follows:
I
Appendix B to Subpart Q
*
*
*
*
*
18. Surface water systems and ground
water systems under the direct
influence of surface water are regulated
under subpart H of 40 CFR 141. Subpart
H community and non-transient noncommunity systems serving ≥10,000
must comply with subpart L DBP MCLs
and disinfectant maximum residual
disinfectant levels (MRDLs) beginning
January 1, 2002. All other community
and non-transient non-community
systems must comply with subpart L
DBP MCLs and disinfectant MRDLs
beginning January 1, 2004. Subpart H
transient non-community systems
serving ≥10,000 that use chlorine
dioxide as a disinfectant or oxidant
must comply with the chlorine dioxide
MRDL beginning January 1, 2002. All
other transient non-community systems
that use chlorine dioxide as a
disinfectant or oxidant must comply
with the chlorine dioxide MRDL
beginning January 1, 2004.
I 19. Community and non-transient
non-community systems must comply
with subpart V TTHM and HAA5 MCLs
of 0.080 mg/L and 0.060 mg/L,
respectively (with compliance
calculated as a locational running
annual average) on the schedule in
§ 141.620.
*
*
*
*
*
I 21. Part 141 is amended by adding
new subpart U to read as follows:
I
Subpart U—Initial Distribution System
Evaluations
141.600 General requirements.
141.601 Standard monitoring.
141.602 System specific studies.
141.603 40/30 certification.
141.604 Very small system waivers.
141.605 Subpart V compliance monitoring
location recommendations.
Subpart U—Initial Distribution System
Evaluations
§ 141.600
General requirements.
(a) The requirements of subpart U of
this part constitute national primary
drinking water regulations. The
regulations in this subpart establish
monitoring and other requirements for
identifying subpart V compliance
monitoring locations for determining
compliance with maximum
contaminant levels for total
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trihalomethanes (TTHM) and haloacetic
acids (five)(HAA5). You must use an
Initial Distribution System Evaluation
(IDSE) to determine locations with
representative high TTHM and HAA5
concentrations throughout your
distribution system. IDSEs are used in
conjunction with, but separate from,
subpart L compliance monitoring, to
If you serve this
population
identify and select subpart V
compliance monitoring locations.
(b) Applicability. You are subject to
these requirements if your system is a
community water system that uses a
primary or residual disinfectant other
than ultraviolet light or delivers water
that has been treated with a primary or
residual disinfectant other than
ultraviolet light; or if your system is a
nontransient noncommunity water
You must submit your standard monitoring plan or system specific study
plan 1 or 40/30 certification 2 to the
State by or receive very small system
waiver from State
system that serves at least 10,000 people
and uses a primary or residual
disinfectant other than ultraviolet light
or delivers water that has been treated
with a primary or residual disinfectant
other than ultraviolet light.
(c) Schedule. (1) You must comply
with the requirements of this subpart on
the schedule in the table in this
paragraph (c)(1).
You must complete your standard
monitoring or system specific study by
You must submit your IDSE report to
the State by 3
Systems that are not part of a combined distribution system and systems that serve the largest population in the combined
distribution system
(i) ≥100,000 ............
(ii) 50,000–99,999 ..
(iii) 10,000–49,999
(iv) <10,000 (CWS
Only).
October 1, 2006 ....................................
April 1, 2007 .........................................
October 1, 2007 ....................................
April 1, 2008 .........................................
September 30, 2008 .............................
March 31, 2009 ....................................
September 30, 2009 .............................
March 31, 2010 ....................................
January 1, 2009.
July 1, 2009.
January 1, 2010.
July 1, 2010.
Other systems that are part of a combined distribution system
(v) Wholesale system or consecutive system.
—at the same time as the system with
the earliest compliance date in the
combined distribution system.
—at the same time as the system with
the earliest compliance date in the
combined distribution system.
—at the same time as the system with
the earliest compliance date in the
combined distribution system.
wwhite on PROD1PC65 with RULES2
1 If, within 12 months after the date identified in this column, the State does not approve your plan or notify you that it has not yet completed its
review, you may consider the plan that you submitted as approved. You must implement that plan and you must complete standard monitoring or
a system specific study no later than the date identified in the third column.
2 You must submit your 40/30 certification under § 141.603 by the date indicated.
3 If, within three months after the date identified in this column (nine months after the date identified in this column if you must comply on the
schedule in paragraph (c)(1)(iii) of this section), the State does not approve your IDSE report or notify you that it has not yet completed its review, you may consider the report that you submitted as approved and you must implement the recommended subpart V monitoring as required.
(2) For the purpose of the schedule in
paragraph (c)(1) of this section, the State
may determine that the combined
distribution system does not include
certain consecutive systems based on
factors such as receiving water from a
wholesale system only on an emergency
basis or receiving only a small
percentage and small volume of water
from a wholesale system. The State may
also determine that the combined
distribution system does not include
certain wholesale systems based on
factors such as delivering water to a
consecutive system only on an
emergency basis or delivering only a
small percentage and small volume of
water to a consecutive system.
(d) You must conduct standard
monitoring that meets the requirements
in § 141.601, or a system specific study
that meets the requirements in
§ 141.602, or certify to the State that you
meet 40/30 certification criteria under
§ 141.603, or qualify for a very small
system waiver under § 141.604.
(1) You must have taken the full
complement of routine TTHM and
HAA5 compliance samples required of
a system with your population and
source water under subpart L of this
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Jkt 208001
part (or you must have taken the full
complement of reduced TTHM and
HAA5 compliance samples required of
a system with your population and
source water under subpart L if you
meet reduced monitoring criteria under
subpart L of this part) during the period
specified in § 141.603(a) to meet the 40/
30 certification criteria in § 141.603.
You must have taken TTHM and HAA5
samples under §§ 141.131 and 141.132
to be eligible for the very small system
waiver in § 141.604.
(2) If you have not taken the required
samples, you must conduct standard
monitoring that meets the requirements
in § 141.601, or a system specific study
that meets the requirements in
§ 141.602.
(e) You must use only the analytical
methods specified in § 141.131, or
otherwise approved by EPA for
monitoring under this subpart, to
demonstrate compliance with the
requirements of this subpart.
(f) IDSE results will not be used for
the purpose of determining compliance
with MCLs in § 141.64.
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§ 141.601
Standard monitoring.
(a) Standard monitoring plan. Your
standard monitoring plan must comply
with paragraphs (a)(1) through (a)(4) of
this section. You must prepare and
submit your standard monitoring plan
to the State according to the schedule in
§ 141.600(c).
(1) Your standard monitoring plan
must include a schematic of your
distribution system (including
distribution system entry points and
their sources, and storage facilities),
with notes indicating locations and
dates of all projected standard
monitoring, and all projected subpart L
compliance monitoring.
(2) Your standard monitoring plan
must include justification of standard
monitoring location selection and a
summary of data you relied on to justify
standard monitoring location selection.
(3) Your standard monitoring plan
must specify the population served and
system type (subpart H or ground
water).
(4) You must retain a complete copy
of your standard monitoring plan
submitted under this paragraph (a),
including any State modification of your
standard monitoring plan, for as long as
E:\FR\FM\04JAR2.SGM
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you are required to retain your IDSE
report under paragraph (c)(4) of this
section.
(b) Standard monitoring. (1) You must
monitor as indicated in the table in this
paragraph (b)(1). You must collect dual
sample sets at each monitoring location.
One sample in the dual sample set must
be analyzed for TTHM. The other
sample in the dual sample set must be
analyzed for HAA5. You must conduct
one monitoring period during the peak
historical month for TTHM levels or
HAA5 levels or the month of warmest
water temperature. You must review
available compliance, study, or
operational data to determine the peak
historical month for TTHM or HAA5
levels or warmest water temperature.
Distribution system monitoring locations 1
Population size
category
Monitoring periods and frequency of
sampling
<500 consecutive systems ......
Source water
type
one (during peak historical
month) 2.
..................................................
four (every 90 days) ................
2
Total per
monitoring
period
Near
entry
points
Average
residence
time
High
TTHM
locations
High
HAA5
locations
1
................
1
2
2
................
1
................
................
1
1
1
..................................................
2
................
................
1
1
..................................................
six (every 60 days) ..................
..................................................
..................................................
..................................................
..................................................
4
8
16
24
32
40
................
1
3
4
6
8
1
2
4
6
8
10
2
3
5
8
10
12
1
2
4
6
8
10
one (during peak historical
month) 2.
..................................................
four (every 90 days) ................
..................................................
..................................................
..................................................
2
1
................
1
2
2
6
8
12
................
................
1
1
2
................
................
1
1
2
1
1
2
3
4
Subpart H
<500 non-consecutive systems
500–3,300 consecutive systems.
500–3,300
non-consecutive
systems.
3,301–9,999 .............................
10,000–49,999 .........................
50,000–249,999 .......................
250,000–999,999 .....................
1,000,000–4,999,999 ...............
≥5,000,000 ...............................
Ground Water
<500 consecutive systems ......
<500 non-consecutive systems
500–9,999 ................................
10,000–99,999 .........................
100,000–499,999 .....................
≥500,000 ..................................
1A
1
1
2
3
4
dual sample set (i.e., a TTHM and an HAA5 sample) must be taken at each monitoring location during each monitoring period.
peak historical month is the month with the highest TTHM or HAA5 levels or the warmest water temperature.
wwhite on PROD1PC65 with RULES2
2 The
(2) You must take samples at locations
other than the existing subpart L
monitoring locations. Monitoring
locations must be distributed
throughout the distribution system.
(3) If the number of entry points to the
distribution system is fewer than the
specified number of entry point
monitoring locations, excess entry point
samples must be replaced equally at
high TTHM and HAA5 locations. If
there is an odd extra location number,
you must take a sample at a high TTHM
location. If the number of entry points
to the distribution system is more than
the specified number of entry point
monitoring locations, you must take
samples at entry points to the
distribution system having the highest
annual water flows.
(4) Your monitoring under this
paragraph (b) may not be reduced under
the provisions of § 141.29 and the State
may not reduce your monitoring using
the provisions of § 142.16(m).
(c) IDSE report. Your IDSE report
must include the elements required in
paragraphs (c)(1) through (c)(4) of this
section. You must submit your IDSE
report to the State according to the
schedule in § 141.600(c).
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(1) Your IDSE report must include all
TTHM and HAA5 analytical results
from subpart L compliance monitoring
and all standard monitoring conducted
during the period of the IDSE as
individual analytical results and LRAAs
presented in a tabular or spreadsheet
format acceptable to the State. If
changed from your standard monitoring
plan submitted under paragraph (a) of
this section, your report must also
include a schematic of your distribution
system, the population served, and
system type (subpart H or ground
water).
(2) Your IDSE report must include an
explanation of any deviations from your
approved standard monitoring plan.
(3) You must recommend and justify
subpart V compliance monitoring
locations and timing based on the
protocol in § 141.605.
(4) You must retain a complete copy
of your IDSE report submitted under
this section for 10 years after the date
that you submitted your report. If the
State modifies the subpart V monitoring
requirements that you recommended in
your IDSE report or if the State approves
alternative monitoring locations, you
must keep a copy of the State’s
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notification on file for 10 years after the
date of the State’s notification. You
must make the IDSE report and any
State notification available for review by
the State or the public.
§ 141.602
System specific studies.
(a) System specific study plan. Your
system specific study plan must be
based on either existing monitoring
results as required under paragraph
(a)(1) of this section or modeling as
required under paragraph (a)(2) of this
section. You must prepare and submit
your system specific study plan to the
State according to the schedule in
§ 141.600(c).
(1) Existing monitoring results. You
may comply by submitting monitoring
results collected before you are required
to begin monitoring under § 141.600(c).
The monitoring results and analysis
must meet the criteria in paragraphs
(a)(1)(i) and (a)(1)(ii) of this section.
(i) Minimum requirements. (A) TTHM
and HAA5 results must be based on
samples collected and analyzed in
accordance with § 141.131. Samples
must be collected no earlier than five
years prior to the study plan submission
date.
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Federal Register / Vol. 71, No. 2 / Wednesday, January 4, 2006 / Rules and Regulations
(B) The monitoring locations and
frequency must meet the conditions
identified in this paragraph (a)(1)(i)(B).
Each location must be sampled once
during the peak historical month for
TTHM levels or HAA5 levels or the
month of warmest water temperature for
every 12 months of data submitted for
that location. Monitoring results must
include all subpart L compliance
monitoring results plus additional
monitoring results as necessary to meet
minimum sample requirements.
Population
size
category
System Type
Number of
monitoring
locations
Number of samples
TTHM
HAA5
Subpart H:
<500
500–3,300
3,301–9,999
10,000–49,999
50,000–
249,999
250,000–
999,999
1,000,000–
4,999,999
≥ 5,000,000
3
3
6
12
24
3
9
36
72
144
3
9
36
72
144
36
216
216
48
288
288
60
360
360
3
3
12
18
3
9
48
72
3
9
48
72
24
96
96
Ground Water:
wwhite on PROD1PC65 with RULES2
<500
500–9,999
10,000–99,999
100,000–
499,999
≥ 500,000
(ii) Reporting monitoring results. You
must report the information in this
paragraph (a)(1)(ii).
(A) You must report previously
collected monitoring results and certify
that the reported monitoring results
include all compliance and noncompliance results generated during the
time period beginning with the first
reported result and ending with the
most recent subpart L results.
(B) You must certify that the samples
were representative of the entire
distribution system and that treatment,
and distribution system have not
changed significantly since the samples
were collected.
(C) Your study monitoring plan must
include a schematic of your distribution
system (including distribution system
entry points and their sources, and
storage facilities), with notes indicating
the locations and dates of all completed
or planned system specific study
monitoring.
(D) Your system specific study plan
must specify the population served and
system type (subpart H or ground
water).
(E) You must retain a complete copy
of your system specific study plan
submitted under this paragraph (a)(1),
including any State modification of your
system specific study plan, for as long
as you are required to retain your IDSE
report under paragraph (b)(5) of this
section.
(F) If you submit previously collected
data that fully meet the number of
samples required under paragraph
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20:53 Jan 03, 2006
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(a)(1)(i)(B) of this section and the State
rejects some of the data, you must either
conduct additional monitoring to
replace rejected data on a schedule the
State approves or conduct standard
monitoring under § 141.601.
(2) Modeling. You may comply
through analysis of an extended period
simulation hydraulic model. The
extended period simulation hydraulic
model and analysis must meet the
criteria in this paragraph (a)(2).
(i) Minimum requirements. (A) The
model must simulate 24 hour variation
in demand and show a consistently
repeating 24 hour pattern of residence
time.
(B) The model must represent the
criteria listed in paragraphs
(a)(2)(i)(B)(1) through (9) of this section.
(1) 75% of pipe volume;
(2) 50% of pipe length;
(3) All pressure zones;
(4) All 12-inch diameter and larger
pipes;
(5) All 8-inch and larger pipes that
connect pressure zones, influence zones
from different sources, storage facilities,
major demand areas, pumps, and
control valves, or are known or expected
to be significant conveyors of water;
(6) All 6-inch and larger pipes that
connect remote areas of a distribution
system to the main portion of the
system;
(7) All storage facilities with standard
operations represented in the model;
and
(8) All active pump stations with
controls represented in the model; and
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(9) All active control valves.
(C) The model must be calibrated, or
have calibration plans, for the current
configuration of the distribution system
during the period of high TTHM
formation potential. All storage facilities
must be evaluated as part of the
calibration process. All required
calibration must be completed no later
than 12 months after plan submission.
(ii) Reporting modeling. Your system
specific study plan must include the
information in this paragraph (a)(2)(ii).
(A) Tabular or spreadsheet data
demonstrating that the model meets
requirements in paragraph (a)(2)(i)(B) of
this section.
(B) A description of all calibration
activities undertaken, and if calibration
is complete, a graph of predicted tank
levels versus measured tank levels for
the storage facility with the highest
residence time in each pressure zone,
and a time series graph of the residence
time at the longest residence time
storage facility in the distribution
system showing the predictions for the
entire simulation period (i.e., from time
zero until the time it takes to for the
model to reach a consistently repeating
pattern of residence time).
(C) Model output showing
preliminary 24 hour average residence
time predictions throughout the
distribution system.
(D) Timing and number of samples
representative of the distribution system
planned for at least one monitoring
period of TTHM and HAA5 dual sample
monitoring at a number of locations no
E:\FR\FM\04JAR2.SGM
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Federal Register / Vol. 71, No. 2 / Wednesday, January 4, 2006 / Rules and Regulations
less than would be required for the
system under standard monitoring in
§ 141.601 during the historical month of
high TTHM. These samples must be
taken at locations other than existing
subpart L compliance monitoring
locations.
(E) Description of how all
requirements will be completed no later
than 12 months after you submit your
system specific study plan.
(F) Schematic of your distribution
system (including distribution system
entry points and their sources, and
storage facilities), with notes indicating
the locations and dates of all completed
system specific study monitoring (if
calibration is complete) and all subpart
L compliance monitoring.
(G) Population served and system
type (subpart H or ground water).
(H) You must retain a complete copy
of your system specific study plan
submitted under this paragraph (a)(2),
including any State modification of your
system specific study plan, for as long
as you are required to retain your IDSE
report under paragraph (b)(7) of this
section.
(iii) If you submit a model that does
not fully meet the requirements under
paragraph (a)(2) of this section, you
must correct the deficiencies and
respond to State inquiries concerning
the model. If you fail to correct
deficiencies or respond to inquiries to
the State’s satisfaction, you must
conduct standard monitoring under
§ 141.601.
(b) IDSE report. Your IDSE report
must include the elements required in
paragraphs (b)(1) through (b)(6) of this
section. You must submit your IDSE
report according to the schedule in
§ 141.600(c).
(1) Your IDSE report must include all
TTHM and HAA5 analytical results
from subpart L compliance monitoring
and all system specific study monitoring
conducted during the period of the
system specific study presented in a
tabular or spreadsheet format acceptable
to the State. If changed from your
system specific study plan submitted
under paragraph (a) of this section, your
IDSE report must also include a
schematic of your distribution system,
the population served, and system type
(subpart H or ground water).
(2) If you used the modeling provision
under paragraph (a)(2) of this section,
you must include final information for
the elements described in paragraph
(a)(2)(ii) of this section, and a 24-hour
time series graph of residence time for
each subpart V compliance monitoring
location selected.
(3) You must recommend and justify
subpart V compliance monitoring
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locations and timing based on the
protocol in § 141.605.
(4) Your IDSE report must include an
explanation of any deviations from your
approved system specific study plan.
(5) Your IDSE report must include the
basis (analytical and modeling results)
and justification you used to select the
recommended subpart V monitoring
locations.
(6) You may submit your IDSE report
in lieu of your system specific study
plan on the schedule identified in
§ 141.600(c) for submission of the
system specific study plan if you believe
that you have the necessary information
by the time that the system specific
study plan is due. If you elect this
approach, your IDSE report must also
include all information required under
paragraph (a) of this section.
(7) You must retain a complete copy
of your IDSE report submitted under
this section for 10 years after the date
that you submitted your IDSE report. If
the State modifies the subpart V
monitoring requirements that you
recommended in your IDSE report or if
the State approves alternative
monitoring locations, you must keep a
copy of the State’s notification on file
for 10 years after the date of the State’s
notification. You must make the IDSE
report and any State notification
available for review by the State or the
public.
§ 141.603
40/30 certification.
(a) Eligibility. You are eligible for 40/
30 certification if you had no TTHM or
HAA5 monitoring violations under
subpart L of this part and no individual
sample exceeded 0.040 mg/L for TTHM
or 0.030 mg/L for HAA5 during an eight
consecutive calendar quarter period
beginning no earlier than the date
specified in this paragraph (a).
If your 40/30
certification is
due
Then your eligibility for 40/30
certification is based on
eight consecutive calendar
quarters of subpart L compliance monitoring results beginning no earlier than 1
487
(b) 40/30 certification. (1) You must
certify to your State that every
individual compliance sample taken
under subpart L of this part during the
periods specified in paragraph (a) of this
section were ≤0.040 mg/L for TTHM and
≤0.030 mg/L for HAA5, and that you
have not had any TTHM or HAA5
monitoring violations during the period
specified in paragraph (a) of this
section.
(2) The State may require you to
submit compliance monitoring results,
distribution system schematics, and/or
recommended subpart V compliance
monitoring locations in addition to your
certification. If you fail to submit the
requested information, the State may
require standard monitoring under
§ 141.601 or a system specific study
under § 141.602.
(3) The State may still require
standard monitoring under § 141.601 or
a system specific study under § 141.602
even if you meet the criteria in
paragraph (a) of this section.
(4) You must retain a complete copy
of your certification submitted under
this section for 10 years after the date
that you submitted your certification.
You must make the certification, all data
upon which the certification is based,
and any State notification available for
review by the State or the public.
§ 141.604
Very small system waivers.
(a) If you serve fewer than 500 people
and you have taken TTHM and HAA5
samples under subpart L of this part,
you are not required to comply with this
subpart unless the State notifies you
that you must conduct standard
monitoring under § 141.601 or a system
specific study under § 141.602.
(b) If you have not taken TTHM and
HAA5 samples under subpart L of this
part or if the State notifies you that you
must comply with this subpart, you
must conduct standard monitoring
under § 141.601 or a system specific
study under § 141.602.
§ 141.605 Subpart V compliance
monitoring location recommendations.
(a) Your IDSE report must include
your recommendations and justification
(1) October 1,
January 2004.
for where and during what month(s)
2006.
TTHM and HAA5 monitoring for
(2) April 1,
January 2004.
subpart V of this part should be
2007.
(3) October 1,
January 2005.
conducted. You must base your
2007.
recommendations on the criteria in
(4) April 1,
January 2005.
paragraphs (b) through (e) of this
2008.
section.
1 Unless you are on reduced monitoring
(b) You must select the number of
under subpart L of this part and were not re- monitoring locations specified in the
quired to monitor during the specified period. If table in this paragraph (b). You will use
you did not monitor during the specified period, you must base your eligibility on compli- these recommended locations as subpart
ance samples taken during the 12 months pre- V routine compliance monitoring
ceding the specified period.
locations, unless State requires different
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Federal Register / Vol. 71, No. 2 / Wednesday, January 4, 2006 / Rules and Regulations
or additional locations. You should
distribute locations throughout the
distribution system to the extent
possible.
Distribution system monitoring location
Population
size category
Source water type
Monitoring
frequency 1
Total per
monitoring
period 2
Highest
TTHM locations
Highest
HAA5 locations
Existing
subpart L
compliance
locations
Subpart H:
<500
500–3,300
3,301–9,999
10,000–
49,999
50,000–
249,999
250,000–
999,999
1,000,000–
4,999,999
≥5,000,000
per
per
per
per
year
quarter
quarter
quarter
2
2
2
4
1
1
1
2
1
1
1
1
....................
per quarter
8
3
3
2
per quarter
12
5
4
3
per quarter
16
6
6
4
per quarter
20
8
7
5
<500
500–9,999
10,000–
99,999
100,000–
499,999
≥500,000
per year
per year
per quarter
2
2
4
1
1
2
1
1
1
1
per quarter
6
3
2
1
per quarter
8
3
3
2
....................
1
Ground water:
1 All
wwhite on PROD1PC65 with RULES2
systems must monitor during month of highest DBP concentrations.
2 Systems on quarterly monitoring must take dual sample sets every 90 days at each monitoring location, except for subpart H systems serving
500–3,300. Systems on annual monitoring and subpart H systems serving 500–3,300 are required to take individual TTHM and HAA5 samples
(instead of a dual sample set) at the locations with the highest TTHM and HAA5 concentrations, respectively. Only one location with a dual sample set per monitoring period is needed if highest TTHM and HAA5 concentrations occur at the same location, and month, if monitored annually).
(c) You must recommend subpart V
compliance monitoring locations based
on standard monitoring results, system
specific study results, and subpart L
compliance monitoring results. You
must follow the protocol in paragraphs
(c)(1) through (c)(8) of this section. If
required to monitor at more than eight
locations, you must repeat the protocol
as necessary. If you do not have existing
subpart L compliance monitoring results
or if you do not have enough existing
subpart L compliance monitoring
results, you must repeat the protocol,
skipping the provisions of paragraphs
(c)(3) and (c)(7) of this section as
necessary, until you have identified the
required total number of monitoring
locations.
(1) Location with the highest TTHM
LRAA not previously selected as a
subpart V monitoring location.
(2) Location with the highest HAA5
LRAA not previously selected as a
subpart V monitoring location.
(3) Existing subpart L average
residence time compliance monitoring
location (maximum residence time
compliance monitoring location for
ground water systems) with the highest
HAA5 LRAA not previously selected as
a subpart V monitoring location.
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(4) Location with the highest TTHM
LRAA not previously selected as a
subpart V monitoring location.
(5) Location with the highest TTHM
LRAA not previously selected as a
subpart V monitoring location.
(6) Location with the highest HAA5
LRAA not previously selected as a
subpart V monitoring location.
(7) Existing subpart L average
residence time compliance monitoring
location (maximum residence time
compliance monitoring location for
ground water systems) with the highest
TTHM LRAA not previously selected as
a subpart V monitoring location.
(8) Location with the highest HAA5
LRAA not previously selected as a
subpart V monitoring location.
(d) You may recommend locations
other than those specified in paragraph
(c) of this section if you include a
rationale for selecting other locations. If
the State approves the alternate
locations, you must monitor at these
locations to determine compliance
under subpart V of this part.
(e) Your recommended schedule must
include subpart V monitoring during the
peak historical month for TTHM and
HAA5 concentration, unless the State
approves another month. Once you have
identified the peak historical month,
and if you are required to conduct
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routine monitoring at least quarterly,
you must schedule subpart V
compliance monitoring at a regular
frequency of every 90 days or fewer.
I 20. Part 141 is amended by adding
new subpart V to read as follows:
Subpart V—Stage 2 Disinfection
Byproducts Requirements
141.620 General requirements.
141.621 Routine monitoring.
141.622 Subpart V monitoring plan.
141.623 Reduced monitoring.
141.624 Additional requirements for
consecutive systems.
141.625 Conditions requiring increased
monitoring.
141.626 Operational evaluation levels.
141.627 Requirements for remaining on
reduced TTHM and HAA5 monitoring
based on subpart L results.
141.628 Requirements for remaining on
increased TTHM and HAA5 monitoring
based on subpart L results.
141.629 Reporting and recordkeeping
requirements.
Subpart V—Stage 2 Disinfection
Byproducts Requirements
§ 141.620
General requirements.
(a) General. The requirements of
subpart V of this part constitute national
primary drinking water regulations. The
regulations in this subpart establish
monitoring and other requirements for
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achieving compliance with maximum
contaminant levels based on locational
running annual averages (LRAA) for
total trihalomethanes (TTHM) and
haloacetic acids (five)(HAA5), and for
achieving compliance with maximum
residual disinfectant residuals for
chlorine and chloramine for certain
consecutive systems.
(b) Applicability. You are subject to
these requirements if your system is a
community water system or a
nontransient noncommunity water
system that uses a primary or residual
disinfectant other than ultraviolet light
489
or delivers water that has been treated
with a primary or residual disinfectant
other than ultraviolet light.
(c) Schedule. You must comply with
the requirements in this subpart on the
schedule in the following table based on
your system type.
You must comply with subpart V monitoring by: 1
If you are this type of system
Systems that are not part of a combined distribution system and systems that serve the largest population in the combined
distribution system
(1)
(2)
(3)
(4)
System
System
System
System
serving
serving
serving
serving
≥ 100,000 ............................................
50,000–99,999 ....................................
10,000–49,999 ....................................
> 10,000 .............................................
April 1, 2012.
October 1, 2012.
October 1, 2013.
October 1, 2013 if no Cryptosporidium monitoring is required under § 141.701(a)(4)
or
October 1, 2014 if Cryptosporidium monitoring is required under § 141.701(a)(4) or
(a)(6)
Other systems that are part of a combined distribution system
(5) Consecutive system or wholesale system ...................
—at the same time as the system with the earliest compliance date in the combined
distribution system.
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1 The State may grant up to an additional 24 months for compliance with MCLs and operational evaluaton levels if you require capital improvements to comply with an MCL.
(6) Your monitoring frequency is
specified in § 141.621(a)(2).
(i) If you are required to conduct
quarterly monitoring, you must begin
monitoring in the first full calendar
quarter that includes the compliance
date in the table in this paragraph (c).
(ii) If you are required to conduct
monitoring at a frequency that is less
than quarterly, you must begin
monitoring in the calendar month
recommended in the IDSE report
prepared under § 141.601 or § 141.602
or the calendar month identified in the
subpart V monitoring plan developed
under § 141.622 no later than 12 months
after the compliance date in this table.
(7) If you are required to conduct
quarterly monitoring, you must make
compliance calculations at the end of
the fourth calendar quarter that follows
the compliance date and at the end of
each subsequent quarter (or earlier if the
LRAA calculated based on fewer than
four quarters of data would cause the
MCL to be exceeded regardless of the
monitoring results of subsequent
quarters). If you are required to conduct
monitoring at a frequency that is less
than quarterly, you must make
compliance calculations beginning with
the first compliance sample taken after
the compliance date.
(8) For the purpose of the schedule in
this paragraph (c), the State may
determine that the combined
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distribution system does not include
certain consecutive systems based on
factors such as receiving water from a
wholesale system only on an emergency
basis or receiving only a small
percentage and small volume of water
from a wholesale system. The State may
also determine that the combined
distribution system does not include
certain wholesale systems based on
factors such as delivering water to a
consecutive system only on an
emergency basis or delivering only a
small percentage and small volume of
water to a consecutive system.
(d) Monitoring and compliance. (1)
Systems required to monitor quarterly.
To comply with subpart V MCLs in
§ 141.64(b)(2), you must calculate
LRAAs for TTHM and HAA5 using
monitoring results collected under this
subpart and determine that each LRAA
does not exceed the MCL. If you fail to
complete four consecutive quarters of
monitoring, you must calculate
compliance with the MCL based on the
average of the available data from the
most recent four quarters. If you take
more than one sample per quarter at a
monitoring location, you must average
all samples taken in the quarter at that
location to determine a quarterly
average to be used in the LRAA
calculation.
(2) Systems required to monitor yearly
or less frequently. To determine
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compliance with subpart V MCLs in
§ 141.64(b)(2), you must determine that
each sample taken is less than the MCL.
If any sample exceeds the MCL, you
must comply with the requirements of
§ 141.625. If no sample exceeds the
MCL, the sample result for each
monitoring location is considered the
LRAA for that monitoring location.
(e) Violation. You are in violation of
the monitoring requirements for each
quarter that a monitoring result would
be used in calculating an LRAA if you
fail to monitor.
§ 141.621
Routine monitoring.
(a) Monitoring. (1) If you submitted an
IDSE report, you must begin monitoring
at the locations and months you have
recommended in your IDSE report
submitted under § 141.605 following the
schedule in § 141.620(c), unless the
State requires other locations or
additional locations after its review. If
you submitted a 40/30 certification
under § 141.603 or you qualified for a
very small system waiver under
§ 141.604 or you are a nontransient
noncommunity water system serving
<10,000, you must monitor at the
location(s) and dates identified in your
monitoring plan in § 141.132(f), updated
as required by § 141.622.
(2) You must monitor at no fewer than
the number of locations identified in
this paragraph (a)(2).
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Federal Register / Vol. 71, No. 2 / Wednesday, January 4, 2006 / Rules and Regulations
Source water type
Population size category
Monitoring
Frequency 1
Distribution
system monitoring location
total per monitoring period 2
Subpart H:
<500 ......................................................................
500–3,300 .............................................................
3,301–9,999 ..........................................................
10,000–49,999 ......................................................
50,000–249,999 ....................................................
250,000–999,999 ..................................................
1,000,000–4,999,999 ............................................
≥ 5,000,000 ..........................................................
per
per
per
per
per
per
per
per
year .........................
quarter ....................
quarter ....................
quarter ....................
quarter ....................
quarter ....................
quarter ....................
quarter ....................
2
2
2
4
8
12
16
20
<500 ......................................................................
500–9,999 .............................................................
10,000–99,999 ......................................................
100,000–499,999 ..................................................
≥ 500,000 .............................................................
per
per
per
per
per
year .........................
year .........................
quarter ....................
quarter ....................
quarter ....................
2
2
4
6
8
Ground Water:
1 All
systems must monitor during month of highest DBP concentrations.
on quarterly monitoring must take dual sample sets every 90 days at each monitoring location, except for subpart H systems serving
500–3,300. Systems on annual monitoring and subpart H systems serving 500–3,300 are required to take individual TTHM and HAA5 samples
(instead of a dual sample set) at the locations with the highest TTHM and HAA5 concentrations, respectively. Only one location with a dual sample set per monitoring period is needed if highest TTHM and HAA5 concentrations occur at the same location (and month, if monitored annually).
2 Systems
(3) If you are an undisinfected system
that begins using a disinfectant other
than UV light after the dates in subpart
U of this part for complying with the
Initial Distribution System Evaluation
requirements, you must consult with the
State to identify compliance monitoring
locations for this subpart. You must
then develop a monitoring plan under
§ 141.622 that includes those
monitoring locations.
(b) Analytical methods. You must use
an approved method listed in § 141.131
for TTHM and HAA5 analyses in this
subpart. Analyses must be conducted by
laboratories that have received
certification by EPA or the State as
specified in § 141.131.
wwhite on PROD1PC65 with RULES2
§ 141.622
Subpart V monitoring plan.
(a)(1) You must develop and
implement a monitoring plan to be kept
on file for State and public review. The
monitoring plan must contain the
elements in paragraphs (a)(1)(i) through
(a)(1)(iv) of this section and be complete
no later than the date you conduct your
initial monitoring under this subpart.
(i) Monitoring locations;
(ii) Monitoring dates;
(iii) Compliance calculation
procedures; and
(iv) Monitoring plans for any other
systems in the combined distribution
system if the State has reduced
monitoring requirements under the
State authority in § 142.16(m).
(2) If you were not required to submit
an IDSE report under either § 141.601 or
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§ 141.602, and you do not have
sufficient subpart L monitoring
locations to identify the required
number of subpart V compliance
monitoring locations indicated in
§ 141.605(b), you must identify
additional locations by alternating
selection of locations representing high
TTHM levels and high HAA5 levels
until the required number of
compliance monitoring locations have
been identified. You must also provide
the rationale for identifying the
locations as having high levels of TTHM
or HAA5. If you have more subpart L
monitoring locations than required for
subpart V compliance monitoring in
§ 141.605(b), you must identify which
locations you will use for subpart V
compliance monitoring by alternating
selection of locations representing high
TTHM levels and high HAA5 levels
until the required number of subpart V
compliance monitoring locations have
been identified.
(b) If you are a subpart H system
serving > 3,300 people, you must submit
a copy of your monitoring plan to the
State prior to the date you conduct your
initial monitoring under this subpart,
unless your IDSE report submitted
under subpart U of this part contains all
the information required by this section.
(c) You may revise your monitoring
plan to reflect changes in treatment,
distribution system operations and
layout (including new service areas), or
other factors that may affect TTHM or
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HAA5 formation, or for State-approved
reasons, after consultation with the
State regarding the need for changes and
the appropriateness of changes. If you
change monitoring locations, you must
replace existing compliance monitoring
locations with the lowest LRAA with
new locations that reflect the current
distribution system locations with
expected high TTHM or HAA5 levels.
The State may also require
modifications in your monitoring plan.
If you are a subpart H system serving >
3,300 people, you must submit a copy
of your modified monitoring plan to the
State prior to the date you are required
to comply with the revised monitoring
plan.
§ 141.623
Reduced monitoring.
(a) You may reduce monitoring to the
level specified in the table in this
paragraph (a) any time the LRAA is
≤0.040 mg/L for TTHM and ≤0.030
mg/L for HAA5 at all monitoring
locations. You may only use data
collected under the provisions of this
subpart or subpart L of this part to
qualify for reduced monitoring. In
addition, the source water annual
average TOC level, before any treatment,
must be ≤4.0 mg/L at each treatment
plant treating surface water or ground
water under the direct influence of
surface water, based on monitoring
conducted under either
§ 141.132(b)(1)(iii) or § 141.132(d).
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Monitoring
frequency 1
Distribution system monitoring location per monitoring period
<500
500–3,300
........................................................
per year ..........................................
3,301–9,999
per year ..........................................
10,000–49,999
per quarter .....................................
50,000–
249,999
250,000–
999,999
1,000,000–
4,999,999
≥ 5,000,000
Source water type
Population
size category
491
per quarter .....................................
monitoring may not be reduced.
1 TTHM and 1 HAA5 sample: one at the location
and during the quarter with the highest TTHM single measurement, one at the location and during
the quarter with the highest HAA5 single measurement; 1 dual sample set per year if the highest
TTHM and HAA5 measurements occurred at the
same location and quarter.
2 dual sample sets: one at the location and during
the quarter with the highest TTHM single measurement, one at the location and during the quarter with the highest HAA5 single measurement.
2 dual sample sets at the locations with the highest
TTHM and highest HAA5 LRAAs.
4 dual sample sets—at the locations with the two
highest TTHM and two highest HAA5 LRAAs.
6 dual sample sets—at the locations with the three
highest TTHM and three highest HAA5 LRAAs.
8 dual sample sets—at the locations with the four
highest TTHM and four highest HAA5 LRAAs.
10 dual sample sets—at the locations with the five
highest TTHM and five highest HAA5 LRAAs.
Subpart H:
per quarter .....................................
per quarter .....................................
per quarter .....................................
Ground Water:
<500
500–9,999
per year ..........................................
100,000–
499,999
≥ 500,000
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per year ..........................................
10,000–99,999
1 Systems
every third year ..............................
per quarter .....................................
per quarter .....................................
1 TTHM and 1 HAA5 sample: one at the location
and during the quarter with the highest TTHM single measurement, one at the location and during
the quarter with the highest HAA5 single measurement; 1 dual sample set per year if the highest
TTHM and HAA5 measurements occurred at the
same location and quarter.
1 TTHM and 1 HAA5 sample: one at the location
and during the quarter with the highest TTHM single measurement, one at the location and during
the quarter with the highest HAA5 single measurement; 1 dual sample set per year if the highest
TTHM and HAA5 measurements occurred at the
same location and quarter.
2 dual sample sets: one at the location and during
the quarter with the highest TTHM single measurement, one at the location and during the quarter with the highest HAA5 single measurement.
2 dual sample sets; at the locations with the highest
TTHM and highest HAA5 LRAAs.
4 dual sample sets at the locations with the two
highest TTHM and two highest HAA5 LRAAs.
on quarterly monitoring must take dual sample sets every 90 days.
(b) You may remain on reduced
monitoring as long as the TTHM LRAA
≤0.040 mg/L and the HAA5 LRAA
≤0.030 mg/L at each monitoring location
(for systems with quarterly reduced
monitoring) or each TTHM sample
≤0.060 mg/L and each HAA5 sample
≤0.045 mg/L (for systems with annual or
less frequent monitoring). In addition,
the source water annual average TOC
level, before any treatment, must be ≤4.0
mg/L at each treatment plant treating
surface water or ground water under the
direct influence of surface water, based
on monitoring conducted under either
§ 141.132(b)(1)(iii) or § 141.132(d).
(c) If the LRAA based on quarterly
monitoring at any monitoring location
exceeds either 0.040 mg/L for TTHM or
0.030 mg/L for HAA5 or if the annual
(or less frequent) sample at any location
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exceeds either 0.060 mg/L for TTHM or
0.045 mg/L for HAA5, or if the source
water annual average TOC level, before
any treatment, >4.0 mg/L at any
treatment plant treating surface water or
ground water under the direct influence
of surface water, you must resume
routine monitoring under § 141.621 or
begin increased monitoring if § 141.625
applies.
(d) The State may return your system
to routine monitoring at the State’s
discretion.
§ 141.624 Additional requirements for
consecutive systems.
If you are a consecutive system that
does not add a disinfectant but delivers
water that has been treated with a
primary or residual disinfectant other
than ultraviolet light, you must comply
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with analytical and monitoring
requirements for chlorine and
chloramines in § 141.131 (c) and
§ 141.132(c)(1) and the compliance
requirements in § 141.133(c)(1)
beginning April 1, 2009, unless required
earlier by the State, and report
monitoring results under § 141.134(c).
§ 141.625 Conditions requiring increased
monitoring.
(a) If you are required to monitor at
a particular location annually or less
frequently than annually under
§ 141.621 or § 141.623, you must
increase monitoring to dual sample sets
once per quarter (taken every 90 days)
at all locations if a TTHM sample is
>0.080 mg/L or a HAA5 sample is
>0.060 mg/L at any location.
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Federal Register / Vol. 71, No. 2 / Wednesday, January 4, 2006 / Rules and Regulations
§ 141.627 Requirements for remaining on
reduced TTHM and HAA5 monitoring based
on subpart L results.
§ 141.626
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(b) You are in violation of the MCL
when the LRAA exceeds the subpart V
MCLs in § 141.64(b)(2), calculated based
on four consecutive quarters of
monitoring (or the LRAA calculated
based on fewer than four quarters of
data if the MCL would be exceeded
regardless of the monitoring results of
subsequent quarters). You are in
violation of the monitoring
requirements for each quarter that a
monitoring result would be used in
calculating an LRAA if you fail to
monitor.
(c) You may return to routine
monitoring once you have conducted
increased monitoring for at least four
consecutive quarters and the LRAA for
every monitoring location is ≤0.060
mg/L for TTHM and ≤0.045 mg/L for
HAA5.
§ 141.628 Requirements for remaining on
increased TTHM and HAA5 monitoring
based on subpart L results.
Operational evaluation levels.
(a) You have exceeded the operational
evaluation level at any monitoring
location where the sum of the two
previous quarters’ TTHM results plus
twice the current quarter’s TTHM result,
divided by 4 to determine an average,
exceeds 0.080 mg/L, or where the sum
of the two previous quarters’ HAA5
results plus twice the current quarter’s
HAA5 result, divided by 4 to determine
an average, exceeds 0.060 mg/L.
(b)(1) If you exceed the operational
evaluation level, you must conduct an
operational evaluation and submit a
written report of the evaluation to the
State no later than 90 days after being
notified of the analytical result that
causes you to exceed the operational
evaluation level. The written report
must be made available to the public
upon request.
(2) Your operational evaluation must
include an examination of system
treatment and distribution operational
practices, including storage tank
operations, excess storage capacity,
distribution system flushing, changes in
sources or source water quality, and
treatment changes or problems that may
contribute to TTHM and HAA5
formation and what steps could be
considered to minimize future
exceedences.
(i) You may request and the State may
allow you to limit the scope of your
evaluation if you are able to identify the
cause of the operational evaluation level
exceedance.
(ii) Your request to limit the scope of
the evaluation does not extend the
schedule in paragraph (b)(1) of this
section for submitting the written
report. The State must approve this
limited scope of evaluation in writing
and you must keep that approval with
the completed report.
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Jkt 208001
You may remain on reduced
monitoring after the dates identified in
§ 141.620(c) for compliance with this
subpart only if you qualify for a 40/30
certification under § 141.603 or have
received a very small system waiver
under § 141.604, plus you meet the
reduced monitoring criteria in
§ 141.623(a), and you do not change or
add monitoring locations from those
used for compliance monitoring under
subpart L of this part. If your monitoring
locations under this subpart differ from
your monitoring locations under subpart
L of this part, you may not remain on
reduced monitoring after the dates
identified in § 141.620(c) for compliance
with this subpart.
If you were on increased monitoring
under § 141.132(b)(1), you must remain
on increased monitoring until you
qualify for a return to routine
monitoring under § 141.625(c). You
must conduct increased monitoring
under § 141.625 at the monitoring
locations in the monitoring plan
developed under § 141.622 beginning at
the date identified in § 141.620(c) for
compliance with this subpart and
remain on increased monitoring until
you qualify for a return to routine
monitoring under § 141.625(c).
§ 141.629 Reporting and recordkeeping
requirements.
(a) Reporting. (1) You must report the
following information for each
monitoring location to the State within
10 days of the end of any quarter in
which monitoring is required:
(i) Number of samples taken during
the last quarter.
(ii) Date and results of each sample
taken during the last quarter.
(iii) Arithmetic average of quarterly
results for the last four quarters for each
monitoring location (LRAA), beginning
at the end of the fourth calendar quarter
that follows the compliance date and at
the end of each subsequent quarter. If
the LRAA calculated based on fewer
than four quarters of data would cause
the MCL to be exceeded regardless of
the monitoring results of subsequent
quarters, you must report this
information to the State as part of the
first report due following the
compliance date or anytime thereafter
that this determination is made. If you
are required to conduct monitoring at a
frequency that is less than quarterly,
you must make compliance calculations
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Sfmt 4700
beginning with the first compliance
sample taken after the compliance date,
unless you are required to conduct
increased monitoring under § 141.625.
(iv) Whether, based on § 141.64(b)(2)
and this subpart, the MCL was violated
at any monitoring location.
(v) Any operational evaluation levels
that were exceeded during the quarter
and, if so, the location and date, and the
calculated TTHM and HAA5 levels.
(2) If you are a subpart H system
seeking to qualify for or remain on
reduced TTHM/HAA5 monitoring, you
must report the following source water
TOC information for each treatment
plant that treats surface water or ground
water under the direct influence of
surface water to the State within 10 days
of the end of any quarter in which
monitoring is required:
(i) The number of source water TOC
samples taken each month during last
quarter.
(ii) The date and result of each sample
taken during last quarter.
(iii) The quarterly average of monthly
samples taken during last quarter or the
result of the quarterly sample.
(iv) The running annual average
(RAA) of quarterly averages from the
past four quarters.
(v) Whether the RAA exceeded 4.0
mg/L.
(3) The State may choose to perform
calculations and determine whether the
MCL was exceeded or the system is
eligible for reduced monitoring in lieu
of having the system report that
information
(b) Recordkeeping. You must retain
any subpart V monitoring plans and
your subpart V monitoring results as
required by § 141.33.
PART 142—NATIONAL PRIMARY
DRINKING WATER REGULATIONS
IMPLEMENTATION
21. The authority citation for part 142
continues to read as follows:
I
Authority: 42 U.S.C. 300f, 300g–1, 300g–2,
300g–3, 300g–4, 300g–5, 300g–6, 300j–4,
300j–9, and 300j–11.
22. Section 142.14 is amended by
adding paragraph (a)(8) to read as
follows:
I
§ 142.14
Records kept by States.
(a) * * *
(8) Any decisions made pursuant to
the provisions of 40 CFR part 141,
subparts U and V of this part.
(i) IDSE monitoring plans, plus any
modifications required by the State,
must be kept until replaced by approved
IDSE reports.
(ii) IDSE reports and 40/30
certifications, plus any modifications
E:\FR\FM\04JAR2.SGM
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required by the State, must be kept until
replaced or revised in their entirety.
(iii) Operational evaluations
submitted by a system must be kept for
10 years following submission.
*
*
*
*
*
23. Section 142.16 is amended by
adding paragraph (m) to read as follows:
I
§ 142.16
wwhite on PROD1PC65 with RULES2
*
*
Special primacy requirements.
*
VerDate Aug<31>2005
*
*
20:53 Jan 03, 2006
Jkt 208001
(m) Requirements for States to adopt
40 CFR part 141, subparts U and V. In
addition to the general primacy
requirements elsewhere in this part,
including the requirements that State
regulations be at least as stringent as
federal requirements, an application for
approval of a State program revision
that adopts 40 CFR part 141, subparts U
and V, must contain a description of
how the State will implement a
procedure for addressing modification
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493
of wholesale system and consecutive
system monitoring on a case-by-case
basis for part 141 subpart V outside the
provisions of § 141.29 of this chapter, if
the State elects to use such an authority.
The procedure must ensure that all
systems have at least one compliance
monitoring location.
*
*
*
*
*
[FR Doc. 06–3 Filed 1–3–06; 8:45 am]
BILLING CODE 6560–50–P
E:\FR\FM\04JAR2.SGM
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]]>Agencies
[Federal Register Volume 71, Number 2 (Wednesday, January 4, 2006)]
[Rules and Regulations]
[Pages 388-493]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 06-3]
[[Page 387]]
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Part II
Environmental Protection Agency
-----------------------------------------------------------------------
40 CFR Parts 9, 141, and 142
National Primary Drinking Water Regulations: Stage 2 Disinfectants and
Disinfection Byproducts Rule; Final Rule
Federal Register / Vol. 71, No. 2 / Wednesday, January 4, 2006 /
Rules and Regulations
[[Page 388]]
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 9, 141, and 142
[EPA-HQ-OW-2002-0043; FRL-8012-1]
RIN 2040-AD38
National Primary Drinking Water Regulations: Stage 2
Disinfectants and Disinfection Byproducts Rule
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: The Environmental Protection Agency (EPA) is promulgating
today's final rule, the Stage 2 Disinfectants and Disinfection
Byproducts Rule (DBPR), to provide for increased protection against the
potential risks for cancer and reproductive and developmental health
effects associated with disinfection byproducts (DBPs). The final Stage
2 DBPR contains maximum contaminant level goals for chloroform,
monochloroacetic acid and trichloroacetic acid; National Primary
Drinking Water Regulations, which consist of maximum contaminant levels
(MCLs) and monitoring, reporting, and public notification requirements
for total trihalomethanes (TTHM) and haloacetic acids (HAA5); and
revisions to the reduced monitoring requirements for bromate. This
document also specifies the best available technologies for the final
MCLs. EPA is also approving additional analytical methods for the
determination of disinfectants and DBPs in drinking water. EPA believes
the Stage 2 DBPR will reduce the potential risks of cancer and
reproductive and developmental health effects associated with DBPs by
reducing peak and average levels of DBPs in drinking water supplies.
The Stage 2 DBPR applies to public water systems (PWSs) that are
community water systems (CWSs) or nontransient noncommunity water
systems (NTNCWs) that add a primary or residual disinfectant other than
ultraviolet light or deliver water that has been treated with a primary
or residual disinfectant other than ultraviolet light.
This rule also makes minor corrections to drinking water
regulations, specifically the Public Notification tables. New endnotes
were added to these tables in recent rulemakings; however, the
corresponding footnote numbering in the tables was not changed. In
addition, this rule makes a minor correction to the Stage 1
Disinfectants and Disinfection Byproducts Rule by replacing a sentence
that was inadvertently removed.
DATES: This final rule is effective on March 6, 2006. For judicial
review purposes, this final rule is promulgated as January 4, 2006. The
incorporation by reference of certain publications listed in the rule
is approved by the Director of the Federal Register as of March 6,
2006.
ADDRESSES: EPA has established a docket for this action under Docket ID
No. EPA-HQ-OW-2002-0043. All documents in the docket are listed on the
https://www.regulations.gov Web site.
Although listed in the index, some information is not publicly
available, e.g., CBI or other information whose disclosure is
restricted by statute. Certain other material, such as copyrighted
material, is not placed on the Internet and will be publicly available
only in hard copy form.
Publicly available docket materials are available either
electronically through https://www.regulations.gov or in hard copy at
the Water Docket, EPA/DC, EPA West, Room B102, 1301 Constitution Ave.,
NW., Washington, DC. The Public Reading Room is open from 10 a.m. to 4
p.m., Monday through Friday, excluding legal holidays. The telephone
number for the Public Reading Room is (202) 566-1744, and the telephone
number for the Water Docket is (202) 566-2426.
FOR FURTHER INFORMATION CONTACT: For technical inquiries, contact Tom
Grubbs, Standards and Risk Management Division, Office of Ground Water
and Drinking Water (MC 4607M), Environmental Protection Agency, 1200
Pennsylvania Ave., NW., Washington, DC 20460; telephone number: (202)
564-5262; fax number: (202) 564-3767; e-mail address:
grubbs.thomas@epa.gov. For general information, contact the Safe
Drinking Water Hotline, Telephone (800) 426-4791. The Safe Drinking
Water Hotline is open Monday through Friday, excluding legal holidays,
from 10 a.m. to 4 p.m. Eastern Time.
SUPPLEMENTARY INFORMATION:
I. General Information
A. Does This Action Apply to Me?
Entities potentially regulated by the Stage 2 DBPR are community
and nontransient noncommunity water systems that add a primary or
residual disinfectant other than ultraviolet light or deliver water
that has been treated with a primary or residual disinfectant other
than ultraviolet light. Regulated categories and entities are
identified in the following chart.
------------------------------------------------------------------------
Examples
of
Category regulated
entities
------------------------------------------------------------------------
Industry..................................................... Community
and
nontransi
ent
noncommun
ity water
systems
that use
a primary
or
residual
disinfect
ant other
than
ultraviol
et light
or
deliver
water
that has
been
treated
with a
primary
or
residual
disinfect
ant other
than
ultraviol
et light.
State, Local, Tribal, or Federal Governments................. Community
and
nontransi
ent
noncommun
ity water
systems
that use
a primary
or
residual
disinfect
ant other
than
ultraviol
et light
or
deliver
water
that has
been
treated
with a
primary
or
residual
disinfect
ant other
than
ultraviol
et light.
------------------------------------------------------------------------
This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be regulated by this
action. This table lists the types of entities that EPA is now aware
could potentially be regulated by this action. Other types of entities
not listed in the table could also be regulated. To determine whether
your facility is regulated by this action, you should carefully examine
the definition of ``public water system'' in Sec. 141.2 and the
section entitled ``coverage'' (Sec. 141.3) in Title 40 of the Code of
Federal Regulations and applicability criteria in Sec. 141.600 and
141.620 of today's proposal. If you have questions regarding the
applicability of this action to a particular entity, contact the person
listed in the preceding FOR FURTHER INFORMATION CONTACT section.
B. How Can I Get Copies of This Document and Other Related Information?
See the ADDRESSES section for information on how to receive a copy
of this document and related information.
Regional contacts:
I. Kevin Reilly, Water Supply Section, JFK Federal Bldg., Room 203,
Boston, MA 02203, (617) 565-3616.
II. Michael Lowy, Water Supply Section, 290 Broadway, 24th Floor, New
[[Page 389]]
York, NY 10007-1866, (212) 637-3830.
III. Jason Gambatese, Drinking Water Section (3WM41), 1650 Arch Street,
Philadelphia, PA 19103-2029, (215) 814-5759.
IV. Robert Burns, Drinking Water Section, 61 Forsyth Street SW.,
Atlanta, GA 30303, (404) 562-9456.
V. Miguel Del Toral, Water Supply Section, 77 W. Jackson Blvd.,
Chicago, IL 60604, (312) 886-5253.
VI. Blake L. Atkins, Drinking Water Section, 1445 Ross Avenue, Dallas,
TX 75202, (214) 665-2297.
VII. Douglas J. Brune, Drinking Water Management Branch, 901 North 5th
Street, Kansas City, KS 66101, (800) 233-0425.
VIII. Bob Clement, Public Water Supply Section (8P2-W-MS), 999 18th
Street, Suite 500, Denver, CO 80202-2466, (303) 312-6653.
IX. Bruce Macler, Water Supply Section, 75 Hawthorne Street, San
Francisco, CA 94105, (415) 972-3569.
X. Wendy Marshall, Drinking Water Unit, 1200 Sixth Avenue (OW-136),
Seattle, WA 98101, (206) 553-1890.
Abbreviations Used in This Document
ASDWA Association of State Drinking Water Administrators
ASTM American Society for Testing and Materials
AWWA American Water Works Association
AwwaRF American Water Works Association Research Foundation
BAT Best available technology
BCAA Bromochloroacetic acid
BDCM Bromodichloromethane
CDBG Community Development Block Grant
CWS Community water system
DBAA Dibromoacetic acid
DBCM Dibromochloromethane
DBP Disinfection byproduct
DBPR Disinfectants and Disinfection Byproducts Rule
DCAA Dichloroacetic acid
EA Economic analysis
EC Enhanced coagulation
EDA Ethylenediamine
EPA United States Environmental Protection Agency
ESWTR Enhanced Surface Water Treatment Rule
FACA Federal Advisory Committee Act
GAC Granular activated carbon
GC/ECD Gas chromatography using electron capture detection
GWR Ground Water Rule
GWUDI Ground water under the direct influence of surface water
HAA5 Haloacetic acids (five) (sum of monochloroacetic acid,
dichloroacetic acid, trichloroacetic acid, monobromoacetic acid, and
dibromoacetic acid)
HAN Haloacetonitriles (trichloroacetonitrile, dichloroacetonitrile,
bromochloroacetonitrile, and dibromoacetonitrile)
IC Ion chromatograph
IC/ICP-MS Ion chromatograph coupled to an inductively coupled plasma
mass spectrometer
IDSE Initial distribution system evaluation
ILSI International Life Sciences Institute
IESWTR Interim Enhanced Surface Water Treatment Rule
IPCS International Programme on Chemical Safety
IRIS Integrated Risk Information System (EPA)
LOAEL Lowest observed adverse effect level
LRAA Locational running annual average
LT1ESTWR Long Term 1 Enhanced Surface Water Treatment Rule
LT2ESTWR Long Term 2 Enhanced Surface Water Treatment Rule
MBAA Monobromoacetic acid
MCAA Monochloroacetic acid
MCL Maximum contaminant level
MCLG Maximum contaminant level goal
M-DBP Microbial and disinfection byproducts mg/L Milligram per liter
MRL Minimum reporting level
MRDL Maximum residual disinfectant level
MRDLG Maximum residual disinfectant level goal
NDMA N-nitrosodimethylamine
NDWAC National Drinking Water Advisory Council
NF Nanofiltration
NOAEL No Observed Adverse Effect Level
NODA Notice of data availability
NPDWR National primary drinking water regulation
NRWA National Rural Water Association
NTNCWS Nontransient noncommunity water system
NTP National Toxicology Program
NTTAA National Technology Transfer and Advancement Act
OMB Office of Management and Budget
PAR Population attributable risk
PE Performance evaluation
PWS Public water system
RAA Running annual average
RFA Regulatory Flexibility Act
RfD Reference dose
RSC Relative source contribution
RUS Rural Utility Service
SAB Science Advisory Board
SBAR Small Business Advisory Review
SBREFA Small Business Regulatory Enforcement Fairness Act
SDWA Safe Drinking Water Act, or the ``Act,'' as amended in 1996
SER Small Entity Representative
SGA Small for gestational age
SUVA Specific ultraviolet absorbance
SWAT Surface Water Analytical Tool
SWTR Surface Water Treatment Rule
TC Total coliforms
TCAA Trichloroacetic acid
TCR Total Coliform Rule
THM Trihalomethane
TOC Total organic carbon
TTHM Total trihalomethanes (sum of four THMs: chloroform,
bromodichloromethane, dibromochloromethane, and bromoform)
TWG Technical work group
UMRA Unfunded Mandates Reform Act
UV 254 Ultraviolet absorption at 254 nm
VSL Value of Statistical Life
WTP Willingness To Pay
Table of Contents
I. General Information
A. Does This Action Apply to Me?
B. How Can I Get Copies of This Document and Other Related
Information?
II. Summary of the Final Rule
A. Why is EPA Promulgating the Stage 2 DBPR?
B. What Does the Stage 2 DBPR Require?
1. Initial Distribution System Evaluation
2. Compliance and monitoring requirements
3. Operational Evaluation Levels
4. Consecutive systems
C. Correction of Sec. 141.132
III. Background
A. Statutory Requirements and Legal Authority
B. What is the Regulatory History of the Stage 2 DBPR and How
Were Stakeholders Involved?
1. Total Trihalomethanes Rule
2. Stage 1 Disinfectants and Disinfection Byproducts Rule
3. Stakeholder involvement
a. Federal Advisory Committee process
b. Other outreach processes
C. Public Health Concerns to be Addressed
1. What are DBPs?
2. DBP Health Effects
a. Cancer health effects
i. Epidemiology
ii. Toxicology
b. Reproductive and developmental health effects
i. Epidemiology
ii. Toxicology
c. Conclusions
D. DBP Occurrence and DBP Control
1. Occurrence
2. Treatment
E. Conclusions for Regulatory Action
IV. Explanation of Today's Action
A. MCLGs
[[Page 390]]
1. Chloroform MCLG
a. Today's rule
b. Background and analysis
c. Summary of major comments
2. HAA MCLGs: TCAA and MCAA
a. Today's rule
b. Background and analysis
c. Summary of major comments
B. Consecutive Systems
1. Today's Rule
2. Background and analysis
3. Summary of major comments
C. LRAA MCLs for TTHM and HAA5
1. Today's rule
2. Background and analysis
3. Summary of major comments
D. BAT for TTHM and HAA5
1. Today's rule
2. Background and analysis
3. Summary of major comments
E. Compliance Schedules
1. Today's rule
2. Background and analysis
3. Summary of major comments
F. Initial Distribution System Evaluation (IDSE)
1. Today's rule
a. Applicability
b. Data collection
i. Standard monitoring
ii. System specific study
iii. 40/30 certification
c. Implementation
2. Background and analysis
a. Standard monitoring
b. Very small system waivers
c. 40/30 certifications
d. System specific studies
e. Distribution System Schematics
3. Summary of major comments
G. Monitoring Requirements and Compliance Determination for TTHM
and HAA5 MCLs
1. Today's Rule
a. IDSE Monitoring
b. Routine Stage 2 Compliance Monitoring
i. Reduced monitoring
ii. Compliance determination
2. Background and Analysis
3. Summary of Major Comments
H. Operational Evaluation Requirements initiated by TTHM and
HAA5 Levels
1. Today's rule
2. Background and analysis
3. Summary of major comments
I. MCL, BAT, and Monitoring for Bromate
1. Today's rule
2. Background and analysis
a. Bromate MCL
b. Criterion for reduced bromate monitoring
3. Summary of major comments
J. Public Notice Requirements
1. Today's rule
2. Background and analysis
3. Summary of major comments
K. Variances and Exemptions
1. Today's Rule
2. Background and Analysis
a. Variances
b. Affordable Treatment Technologies for Small Systems
c. Exemptions
3. Summary of major comments
L. Requirements for Systems to Use Qualified Operators
M. System Reporting and Recordkeeping Requirements
1. Today's rule
2. Summary of major comments
N. Approval of Additional Analytical Methods
1. Today's Rule
2. Background and Analysis
O. Laboratory Certification and Approval
1. PE acceptance criteria
a. Today's rule
b. Background and analysis
c. Summary of major comments
2. Minimum reporting limits
a. Today's rule
b. Background and analysis
c. Summary of major comments
P. Other regulatory changes
V. State Implementation
A. Today's rule
1. State Primacy Requirements for Implementation Flexibility
2. State recordkeeping requirements
3. State reporting requirements
4. Interim primacy
5. IDSE implementation
B. Background and Analysis
C. Summary of Major Comments
VI. Economic Analysis
A. Regulatory Alternatives Considered
B. Analyses that Support Today's Final Rule
1. Predicting water quality and treatment changes
2. Estimating benefits
3. Estimating costs
4. Comparing regulatory alternatives
C. Benefits of the Stage 2 DBPR
1. Nonquantified benefits
2. Quantified benefits
3. Timing of benefits accrual
D. Costs of the Stage 2 DBPR
1. Total annualized present value costs
2. PWS costs
a. IDSE costs
b. PWS treatment costs
c. Monitoring costs
3. State/Primacy agency costs
4. Non-quantified costs
E. Household Costs of the Stage 2 DBPR
F. Incremental Costs and Benefits of the Stage 2 DBPR
G. Benefits From the Reduction of Co-occurring Contaminants
H. Potential Risks From Other Contaminants
1. Emerging DBPs
2. N-nitrosamines
3. Other DBPs
I. Effects of the Contaminant on the General Population and
Groups within the General Population that are Identified as Likely
To Be at Greater Risk of Adverse Health Effects
J. Uncertainties in the Risk, Benefit, and Cost Estimates for
the Stage 2 DBPR
K. Benefit/Cost Determination for the Stage 2 DBPR
L. Summary of Major Comments
1. Interpretation of health effects studies
2. Derivation of benefits
3. Use of SWAT
5. Unanticipated risk issues
6. Valuation of cancer cases avoided
VII. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review
B. Paperwork Reduction Act
C. Regulatory Flexibility Act
D. Unfunded Mandates Reform Act
E. Executive Order 13132: Federalism
F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
G. Executive Order 13045: Protection of Children from
Environmental Health Risks and Safety Risks
H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
I. National Technology Transfer and Advancement Act
J. Executive Order 12898: Federal Actions to Address
Environmental Justice in Minority Populations or Low-Income
Populations
K. Consultations with the Science Advisory Board, National
Drinking Water Advisory Council, and the Secretary of Health and
Human Services
L. Plain Language
M. Analysis of the Likely Effect of Compliance With the Stage 2
DBPR on the Technical, Managerial, and Financial Capacity of Public
Water Systems
N. Congressional Review Act
VIII. References
II. Summary of the Final Rule
A. Why is EPA Promulgating the Stage 2 DBPR?
The Environmental Protection Agency is finalizing the Stage 2
Disinfectants and Disinfection Byproduct Rule (DBPR) to reduce
potential cancer risks and address concerns with potential reproductive
and developmental risks from DBPs. The Agency is committed to ensuring
that all public water systems provide clean and safe drinking water.
Disinfectants are an essential element of drinking water treatment
because of the barrier they provide against harmful waterborne
microbial pathogens. However, disinfectants react with naturally
occurring organic and inorganic matter in source water and distribution
systems to form disinfection byproducts (DBPs) that may pose health
risks. The Stage 2 DBPR is designed to reduce the level of exposure
from DBPs without undermining the control of microbial pathogens. The
Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR) is being
finalized and implemented simultaneously with the Stage 2 DBPR to
ensure that drinking water is microbiologically safe at the limits set
for DBPs.
Congress required EPA to promulgate the Stage 2 DBPR as part of the
1996 Safe Drinking Water Act (SDWA) Amendments (section 1412(b)(2)(C)).
The Stage 2 DBPR augments the Stage 1 DBPR that was finalized in 1998
(63 FR 69390, December 16, 1998) (USEPA
[[Page 391]]
1998a). The goal of the Stage 2 DBPR is to target the highest risk
systems for changes beyond those required for Stage 1 DBPR. Today's
rule reflects consensus recommendations from the Stage 2 Microbial/
Disinfection Byproducts (M-DBP) Federal Advisory Committee (the
Advisory Committee) as well as public comments.
New information on health effects, occurrence, and treatment has
become available since the Stage 1 DBPR that supports the need for the
Stage 2 DBPR. EPA has completed a more extensive analysis of health
effects, particularly reproductive and developmental endpoints,
associated with DBPs since the Stage 1 DBPR. Some recent studies on
both human epidemiology and animal toxicology have shown possible
associations between chlorinated drinking water and reproductive and
developmental endpoints such as spontaneous abortion, stillbirth,
neural tube and other birth defects, intrauterine growth retardation,
and low birth weight. While results of these studies have been mixed,
EPA believes they support a potential hazard concern. New epidemiology
and toxicology studies evaluating bladder, colon, and rectal cancers
have increased the weight of evidence linking these health effects to
DBP exposure. The large number of people (more than 260 million
Americans) exposed to DBPs and the potential cancer, reproductive, and
developmental risks have played a significant role in EPA's decision to
move forward with regulatory changes that target lowering DBP exposures
beyond the requirements of the Stage 1 DBPR.
While the Stage 1 DBPR is predicted to provide a major reduction in
DBP exposure, national survey data suggest that some customers may
receive drinking water with elevated, or peak, DBP concentrations even
when their distribution system is in compliance with the Stage 1 DBPR.
Some of these peak concentrations are substantially greater than the
Stage 1 DBPR maximum contaminant levels (MCLs) and some customers
receive these elevated levels of DBPs on a consistent basis. The new
survey results also show that Stage 1 DBPR monitoring sites may not be
representative of higher DBP concentrations that occur in distribution
systems. In addition, new studies indicate that cost-effective
technologies including ultraviolet light (UV) and granular activated
carbon (GAC) may be very effective at lowering DBP levels. EPA's
analysis of this new occurrence and treatment information indicates
that significant public health benefits may be achieved through
further, cost-effective reductions of DBPs in distribution systems.
The Stage 2 DBPR presents a risk-targeting approach to reduce risks
from DBPs. The new requirements provide for more consistent, equitable
protection from DBPs across the entire distribution system and the
reduction of DBP peaks. New risk-targeting provisions require systems
to first identify their risk level; then, only those systems with the
greatest risk will need to make operational or treatment changes. The
Stage 2 DBPR, in conjunction with the LT2ESWTR, will help public water
systems deliver safer water to Americans with the benefits of
disinfection to control pathogens and with fewer risks from DBPs.
B. What Does the Stage 2 DBPR Require?
The risk-targeting components of the Stage 2 DBPR focus the
greatest amount of change where the greatest amount of risk may exist.
Therefore, the provisions of the Stage 2 DBPR focus first on
identifying the higher risks through the Initial Distribution System
Evaluation (IDSE). The rule then addresses reducing exposure and
lowering DBP peaks in distribution systems by using a new method to
determine MCL compliance (locational running annual average (LRAA)),
defining operational evaluation levels, and regulating consecutive
systems. This section briefly describes the requirements of this final
rule. More detailed information on the regulatory requirements for this
rule can be found in Section IV.
1. Initial Distribution System Evaluation
The first provision, designed to identify higher risk systems, is
the Initial Distribution System Evaluation (IDSE). The purpose of the
IDSE is to identify Stage 2 DBPR compliance monitoring sites that
represent each system's highest levels of DBPs. Because Stage 2 DBPR
compliance will be determined at these new monitoring sites, only those
systems that identify elevated concentrations of TTHM and HAA5 will
need to make treatment or process changes to bring the system into
compliance with the Stage 2 DBPR. By identifying compliance monitoring
sites with the highest concentrations of TTHM and HAA5 in each system's
distribution system, the IDSE will offer increased assurance that MCLs
are being met across the distribution system and that customers are
receiving more equitable public health protection. Both treatment
changes and awareness of TTHM and HAA5 levels resulting from the IDSE
will allow systems to better control for distribution system peaks.
The IDSE is designed to offer flexibility to public water systems.
The IDSE requires TTHM and HAA5 monitoring for one year on a regular
schedule that is determined by source water type and system size.
Alternatively, systems have the option of performing a site-specific
study based on historical data, water distribution system models, or
other data; and waivers are available under certain circumstances. The
IDSE requirements are discussed in Sections IV.E, IV.F., and IV.G of
this preamble and in subpart U of the rule language.
2. Compliance and Monitoring Requirements
As in Stage 1, the Stage 2 DBPR focuses on monitoring for and
reducing concentrations of two classes of DBPs: total trihalomethanes
(TTHM) and haloacetic acids (HAA5). These two groups of DBPs act as
indicators for the various byproducts that are present in water
disinfected with chlorine or chloramine. This means that concentrations
of TTHM and HAA5 are monitored for compliance, but their presence in
drinking water is representative of many other chlorination DBPs that
may also occur in the water; thus, a reduction in TTHM and HAA5
generally indicates an overall reduction of DBPs.
The second provision of the Stage 2 DBPR is designed to address
spatial variations in DBP exposure through a new compliance calculation
(referred to as locational running annual average) for TTHM and HAA5
MCLs. The MCL values remain the same as in the Stage 1. The Stage 1
DBPR running annual average (RAA) calculation allowed some locations
within a distribution system to have higher DBP annual averages than
others as long as the system-wide average was below the MCL. The Stage
2 DBPR bases compliance on a locational running annual average (LRAA)
calculation, where the annual average at each sampling location in the
distribution system will be used to determine compliance with the MCLs
of 0.080 mg/L and 0.060 mg/L for TTHM and HAA5, respectively. The LRAA
will reduce exposures to high DBP concentrations by ensuring that each
monitoring site is in compliance with the MCLs as an annual average,
while providing all customers drinking water that more consistently
meets the MCLs. A more detailed discussion of Stage 2 DBPR MCL
requirements can be found in Sections IV.C, IV.E, and IV.G of this
preamble and in Sec. 141.64(b)(2) and (3) and subpart V of the rule
language.
The number of compliance monitoring sites is based on the
[[Page 392]]
population served and the source water type. EPA believes that
population-based monitoring provides better risk-targeting and is
easier to implement. Section IV.G describes population-based monitoring
and how it affects systems complying with this rule.
The Stage 2 DBPR includes new MCLGs for chloroform,
monochloroacetic acid, and trichloroacetic acid, but these new MCLGs do
not affect the MCLs for TTHM or HAA5.
3. Operational Evaluation Levels
The IDSE and LRAA calculation will lead to lower DBP concentrations
overall and reduce short term exposures to high DBP concentrations in
certain areas, but this strengthened approach to regulating DBPs will
still allow individual DBP samples above the MCL even when systems are
in compliance with the Stage 2 DBPR. Today's rule requires systems that
exceed operational evaluation levels (referred to as significant
excursions in the proposed rule) to evaluate system operational
practices and identify opportunities to reduce DBP concentrations in
the distribution system. This provision will curtail peaks by providing
systems with a proactive approach to remain in compliance. Operational
evaluation requirements are discussed in greater detail in Section
IV.H.
4. Consecutive Systems
The Stage 2 DBPR also contains provisions for regulating
consecutive systems, defined in the Stage 2 DBPR as public water
systems that buy or otherwise receive some or all of their finished
water from another public water system. Uniform regulation of
consecutive systems provided by the Stage 2 DBPR will ensure that
consecutive systems deliver drinking water that meets applicable DBP
standards, thereby providing better, more equitable public health
protection. More information on regulation of consecutive systems can
be found in Sections IV.B, IV.E, and IV.G.
C. Correction of Sec. 141.132
Section 553 of the Administrative Procedure Act, 5 U.S.C.
553(b)(B), provides that, when an agency for good cause finds that
notice and public procedure are impracticable, unnecessary, or contrary
to the public interest, the agency may issue a rule without providing
prior notice and an opportunity for public comment. In addition to
promulgating the Stage 2 regulations, this rule also makes a minor
correction to the National Primary Drinking Water Regulations,
specifically the Stage 1 Disinfection Byproducts Rule. This rule
corrects a technical error made in the January 16, 2001, Federal
Register Notice (66 FR 3769) (see page 3770). This rule restores the
following sentence that was inadvertently removed from Sec. 141.132
(b)(1)(iii), ``Systems on a reduced monitoring schedule may remain on
that reduced schedule as long as the average of all samples taken in
the year (for systems which must monitor quarterly) or the result of
the sample (for systems which must monitor no more frequently than
annually) is no more than 0.060 mg/L and 0.045 mg/L for TTHMs and HAA5,
respectively.'' This text had been part of the original regulation when
it was codified in the CFR on December 16, 1998. However, as a result
of a subsequent amendment to that regulatory text, the text discussed
today was removed. EPA recognized the error only after publication of
the new amendment, and is now correcting the error. EPA is merely
restoring to the CFR language that EPA had promulgated on December 16,
1998. EPA is not creating any new rights or obligations by this
technical correction. Thus, additional notice and public comment is not
necessary. EPA finds that this constitutes ``good cause'' under 5
U.S.C. 553(b)(B).
III. Background
A combination of factors influenced the development of the Stage 2
DBPR. These include the initial 1992-1994 Microbial and Disinfection
Byproduct (M-DBP) stakeholder deliberations and EPA's Stage 1 DBPR
proposal (USEPA 1994); the 1996 Safe Drinking Water Act (SDWA)
Amendments; the 1996 Information Collection Rule; the 1998 Stage 1
DBPR; new data, research, and analysis on disinfection byproduct (DBP)
occurrence, treatment, and health effects since the Stage 1 DBPR; and
the Stage 2 DBPR Microbial and Disinfection Byproducts Federal Advisory
Committee. The following sections provide summary background
information on these subjects. For additional information, see the
proposed Stage 2 DBPR and supporting technical material where cited (68
FR 49548, August 18, 2003) (USEPA 2003a).
A. Statutory Requirements and Legal Authority
The SDWA, as amended in 1996, authorizes EPA to promulgate a
national primary drinking water regulation (NPDWR) and publish a
maximum contaminant level goal (MCLG) for any contaminant the
Administrator determines ``may have an adverse effect on the health of
persons,'' is ``known to occur or there is a substantial likelihood
that the contaminant will occur in public water systems with a
frequency and at levels of public health concern,'' and for which ``in
the sole judgement of the Administrator, regulation of such contaminant
presents a meaningful opportunity for health risk reduction for persons
served by public water systems'' (SDWA section 1412(b)(1)(A)). MCLGs
are non-enforceable health goals set at a level at which ``no known or
anticipated adverse effects on the health of persons occur and which
allows an adequate margin of safety.'' These health goals are published
at the same time as the NPDWR (SDWA sections 1412(b)(4) and
1412(a)(3)).
SDWA also requires each NPDWR for which an MCLG is established to
specify an MCL that is as close to the MCLG as is feasible (sections
1412(b)(4) and 1401(1)(C)). The Agency may also consider additional
health risks from other contaminants and establish an MCL ``at a level
other than the feasible level, if the technology, treatment techniques,
and other means used to determine the feasible level would result in an
increase in the health risk from drinking water by--(i) increasing the
concentration of other contaminants in drinking water; or (ii)
interfering with the efficacy of drinking water treatment techniques or
processes that are used to comply with other national primary drinking
water regulations'' (section 1412(b)(5)(A)). When establishing an MCL
or treatment technique under this authority, ``the level or levels or
treatment techniques shall minimize the overall risk of adverse health
effects by balancing the risk from the contaminant and the risk from
other contaminants the concentrations of which may be affected by the
use of a treatment technique or process that would be employed to
attain the maximum contaminant level or levels'' (section
1412(b)(5)(B)). In today's rule, the Agency is establishing MCLGs and
MCLs for certain DBPs, as described in Section IV.
Finally, section 1412(b)(2)(C) of the Act requires EPA to
promulgate a Stage 2 DBPR. Consistent with statutory provisions for
risk balancing (section 1412(b)(5)(B)), EPA is finalizing the LT2ESWTR
concurrently with the Stage 2 DBPR to ensure simultaneous protection
from microbial and DBP risks.
B. What is the Regulatory History of the Stage 2 DBPR and How Were
Stakeholders Involved?
This section first summarizes the existing regulations aimed at
controlling
[[Page 393]]
levels of DBPs in drinking water. The Stage 2 DBPR establishes
regulatory requirements beyond these rules that target high risk
systems and provide for more equitable protection from DBPs across the
entire distribution system. Next, this section summarizes the extensive
stakeholder involvement in the development of the Stage 2 DBPR.
1. Total Trihalomethanes Rule
The first rule to regulate DBPs was promulgated on November 29,
1979. The Total Trihalomethanes Rule (44 FR 68624, November 29, 1979)
(USEPA 1979) set an MCL of 0.10 mg/L for total trihalomethanes (TTHM).
Compliance was based on the running annual average (RAA) of quarterly
averages of all samples collected throughout the distribution system.
This TTHM standard applied only to community water systems using
surface water and/or ground water that served at least 10,000 people
and added a disinfectant to the drinking water during any part of the
treatment process.
2. Stage 1 Disinfectants and Disinfection Byproducts Rule
The Stage 1 DBPR, finalized in 1998 (USEPA 1998a), applies to all
community and nontransient noncommunity water systems that add a
chemical disinfectant to water. The rule established maximum residual
disinfectant level goals (MRDLGs) and enforceable maximum residual
disinfectant level (MRDL) standards for three chemical disinfectants--
chlorine, chloramine, and chlorine dioxide; maximum contaminant level
goals (MCLGs) for three trihalomethanes (THMs), two haloacetic acids
(HAAs), bromate, and chlorite; and enforceable maximum contaminant
level (MCL) standards for TTHM, five haloacetic acids (HAA5), bromate
(calculated as running annual averages (RAAs)), and chlorite (based on
daily and monthly sampling). The Stage 1 DBPR uses TTHM and HAA5 as
indicators of the various DBPs that are present in disinfected water.
Under the Stage 1 DBPR, water systems that use surface water or ground
water under the direct influence of surface water and use conventional
filtration treatment are required to remove specified percentages of
organic materials, measured as total organic carbon (TOC), that may
react with disinfectants to form DBPs. Removal is achieved through
enhanced coagulation or enhanced softening, unless a system meets one
or more alternative compliance criteria.
The Stage 1 DBPR was one of the first rules to be promulgated under
the 1996 SDWA Amendments (USEPA 1998a). EPA finalized the Interim
Enhanced Surface Water Treatment Rule (63 FR 69477, December 16, 1998)
(USEPA 1998b) at the same time as the Stage 1 DBPR to ensure
simultaneous compliance and address risk tradeoff issues. Both rules
were products of extensive Federal Advisory Committee deliberations and
final consensus recommendations in 1997.
3. Stakeholder Involvement
a. Federal Advisory Committee process. EPA reconvened the M-DBP
Advisory Committee in March 1999 to develop recommendations on issues
pertaining to the Stage 2 DBPR and LT2ESWTR. The Stage 2 M-DBP Advisory
Committee consisted of 21 organizational members representing EPA,
State and local public health and regulatory agencies, local elected
officials, Native American Tribes, large and small drinking water
suppliers, chemical and equipment manufacturers, environmental groups,
and other stakeholders. Technical support for the Advisory Committee's
discussions was provided by a technical working group established by
the Advisory Committee. The Advisory Committee held ten meetings from
September 1999 to July 2000, which were open to the public, with an
opportunity for public comment at each meeting.
The Advisory Committee carefully considered extensive new data on
the occurrence and health effects of DBPs, as well as costs and
potential impacts on public water systems. In addition, they considered
risk tradeoffs associated with treatment changes. Based upon this
detailed technical evaluation, the committee concluded that a targeted
protective public health approach should be taken to address exposure
to DBPs beyond the requirements of the Stage 1 DBPR. While there had
been substantial research to date, the Advisory Committee also
concluded that significant uncertainty remained regarding the risk
associated with DBPs in drinking water. After reaching these
conclusions, the Advisory Committee developed an Agreement in Principle
(65 FR 83015, December 29, 2000) (USEPA 2000a) that laid out their
consensus recommendations on how to further control DBPs in public
water systems, which are reflected in today's final rule.
In the Agreement in Principle, the Advisory Committee recommended
maintaining the MCLs for TTHM and HAA5 at 0.080 mg/L and 0.060 mg/L,
respectively, but changing the compliance calculation in two phases to
facilitate systems moving from the running annual average (RAA)
calculation to a locational running annual average (LRAA) calculation.
In the first phase, systems would continue to comply with the Stage 1
DBPR MCLs as RAAs and, at the same time, comply with MCLs of 0.120 mg/L
for TTHM and 0.100 mg/L for HAA5 calculated as LRAAs. RAA calculations
average all samples collected within a distribution system over a one-
year period, but LRAA calculations average all samples taken at each
individual sampling location in a distribution system during a one-year
period. Systems would also carry out an Initial Distribution System
Evaluation (IDSE) to select compliance monitoring sites that reflect
higher TTHM and HAA5 levels occurring in the distribution system. The
second phase of compliance would require MCLs of 0.080 mg/L for TTHM
and 0.060 mg/L for HAA5, calculated as LRAAs at individual monitoring
sites identified through the IDSE. The first phase has been dropped in
the final rule, as discussed in section IV.C.
The Agreement in Principle also provided recommendations for
simultaneous compliance with the LT2ESWTR so that the reduction of DBPs
does not compromise microbial protection. The complete text of the
Agreement in Principle (USEPA 2000a) can be found online at
www.regulations.gov.
b. Other outreach processes. EPA worked with stakeholders to
develop the Stage 2 DBPR through various outreach activities other than
the M-DBP Federal Advisory Committee process. The Agency consulted with
State, local, and Tribal governments; the National Drinking Water
Advisory Committee (NDWAC); the Science Advisory Board (SAB); and Small
Entity Representatives (SERs) and small system operators (as part of an
Agency outreach initiative under the Regulatory Flexibility Act).
Section VII includes a complete description of the many stakeholder
activities which contributed to the development of the Stage 2 DBPR.
Additionally, EPA posted a pre-proposal draft of the Stage 2 DBPR
preamble and regulatory language on an EPA Internet site on October 17,
2001. This public review period allowed readers to comment on the Stage
2 DBPR's consistency with the Agreement in Principle of the Stage 2 M-
DBP Advisory Committee. EPA received important suggestions on this pre-
proposal draft from 14 commenters, which included public water systems,
State governments, laboratories, and other stakeholders.
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C. Public Health Concerns to be Addressed
EPA is promulgating the Stage 2 rule to reduce the potential risks
of cancer and reproductive and developmental health effects from DBPs.
In addition, the provisions of the Stage 2 DBPR provide for more
equitable public health protection. Sections C and D describe the
general basis for this public health concern through reviewing
information in the following areas: the health effects associated with
DBPs, DBP occurrence, and the control of DBPs.
1. What Are DBPs?
Chlorine has been widely used to kill disease-causing microbes in
drinking water. The addition of chlorine in PWSs across the U.S. to
kill microbial pathogens in the water supply has been cited as one of
the greatest public health advances of the twentieth century (Okun
2003). For example, during the decade 1880-1890, American cities
experienced an average mortality rate of 58 per 100,000 from typhoid,
which was commonly transmitted through contaminated water. By 1938,
this rate had fallen to 0.67 deaths per 100,000, largely due to
improved treatment of drinking water (Blake 1956).
During the disinfection process, organic and inorganic material in
source waters can combine with chlorine and certain other chemical
disinfectants to form DBPs. More than 260 million people in the U.S.
are exposed to disinfected water and DBPs (USEPA 2005a). Although
chlorine is the most commonly applied disinfectant, other
disinfectants, including ozone, chlorine dioxide, chloramine, and
ultraviolet radiation, are in use. In combination with these, all
surface water systems must also use either chlorine or chloramine to
maintain a disinfectant residual in their distribution system. The kind
of disinfectant used can produce different types and levels of
disinfectant byproducts in the drinking water.
Many factors affect the amount and kinds of DBPs in drinking water.
Areas in the distribution system that have had longer contact time with
chemical disinfectants tend to have higher levels of DBPs, such as
sites farther from the treatment plant, dead ends in the system, and
small diameter pipes. The makeup and source of the water also affect
DBP formation. Different types of organic and inorganic material will
form different types and levels of DBPs. Other factors, such as water
temperature, season, pH, and location within the water purification
process where disinfectants are added, can affect DBP formation within
and between water systems.
THMs and HAAs are widely occurring classes of DBPs formed during
disinfection with chlorine and chloramine. The four THMs (TTHM) and
five HAAs (HAA5) measured and regulated in the Stage 2 DBPR act as
indicators for DBP occurrence. There are other known DBPs in addition
to a variety of unidentified DBPs present in disinfected water. THMs
and HAAs typically occur at higher levels than other known and
unidentified DBPs (McGuire et al. 2002; Weinberg et al. 2002). The
presence of TTHM and HAA5 is representative of the occurrence of many
other chlorination DBPs; thus, a reduction in the TTHM and HAA5
generally indicates an overall reduction of DBPs.
2. DBP Health Effects
Since the mid 1980's, epidemiological studies have supported a
potential association between bladder cancer and chlorinated water and
possibly also with colon and rectal cancers. In addition, more recent
health studies have reported potential associations between chlorinated
drinking water and reproductive and developmental health effects.
Based on a collective evaluation of both the human epidemiology and
animal toxicology data on cancer and reproductive and developmental
health effects discussed below and in consideration of the large number
of people exposed to chlorinated byproducts in drinking water (more
than 260 million), EPA concludes that (1) new cancer data since Stage 1
strengthen the evidence of a potential association of chlorinated water
with bladder cancer and suggests an association for colon and rectal
cancers, (2) current reproductive and developmental health effects data
do not support a conclusion at this time as to whether exposure to
chlorinated drinking water or disinfection byproducts causes adverse
developmental or reproductive health effects, but do support a
potential health concern, and (3) the combined health data indicate a
need for public health protection beyond that provided by the Stage 1
DBPR.
This section summarizes the key information in the areas of cancer,
reproductive, and developmental health studies that EPA used to arrive
at these conclusions. Throughout this writeup, EPA uses `weight of
evidence,' `causality,' and `hazard' as follows:
A `weight of evidence' evaluation is a collective
evaluation of all pertinent information. Judgement about the weight of
evidence involves considerations of the quality and adequacy of data
and consistency of responses. These factors are not scored mechanically
by adding pluses and minuses; they are judged in combination.
Criteria for determining `causality' include consistency,
strength, and specificity of association, a temporal relationship, a
biological gradient (dose-response relationship), biological
plausibility, coherence with multiple lines of evidence, evidence from
human populations, and information on agent's structural analogues
(USEPA 2005i). Additional considerations for individual study findings
include reliable exposure data, statistical power and significance, and
freedom from bias and confounding.
The term `hazard' describes not a definitive conclusion,
but the possibility that a health effect may be attributed to a certain
exposure, in this case chlorinated water. Analyses done for the Stage 2
DBPR follow the 1999 EPA Proposed Guidelines for Carcinogenic Risk
Assessment (USEPA 1999a). In March 2005, EPA updated and finalized the
Cancer Guidelines and a Supplementary Children's Guidance, which
include new considerations on mode of action for cancer risk
determination and additional potential risks due to early childhood
exposure (USEPA 2005i; USEPA 2005j). Conducting the cancer evaluation
using the 2005 Cancer Guidelines would not result in any change from
the existing analysis. With the exception of chloroform, no mode of
action has been established for other specific regulated DBPs. Although
some of the DBPs have given mixed mutagenicity and genotoxicity
results, having a positive mutagenicity study does not necessarily mean
that a chemical has a mutagenic mode of action. The extra factor of
safety for children's health protection does not apply because the new
Supplementary Children's Guidance requires application of the
children's factor only when a mutagenic mode of action has been
identified.
a. Cancer health effects. The following section briefly discusses
cancer epidemiology and toxicology information EPA analyzed and some
conclusions of these studies and reports. Further discussion of these
studies and EPA's conclusions can be found in the proposed Stage 2 DBPR
(USEPA 2003a) and the Economic Analysis for the Final Stage 2
Disinfectants and Disinfection Byproducts Rule (Economic Analysis (EA))
(USEPA 2005a).
Human epidemiology studies and animal toxicology studies have
[[Page 395]]
examined associations between chlorinated drinking water or DBPs and
cancer. While EPA cannot conclude there is a causal link between
exposure to chlorinated surface water and cancer, EPA believes that the
available research indicates a potential association between bladder
cancer and exposure to chlorinated drinking water or DBPs. EPA also
believes the available research suggests a possible association between
rectal and colon cancers and exposure to chlorinated drinking water or
DBPs. This is based on EPA's evaluation of all available cancer
studies. The next two sections focus on studies published since the
Stage 1 DBPR. Conclusions are based on the research as a whole.
i. Epidemiology. A number of epidemiological studies have been
conducted to investigate the relationship between exposure to
chlorinated drinking water and various cancers. These studies
contribute to the overall evidence on potential human health hazards
from exposure to chlorinated drinking water.
Epidemiology studies provide useful health effects information
because they reflect human exposure to a drinking water DBP mixture
through multiple routes of intake such as ingestion, inhalation and
dermal absorption. The greatest difficulty with conducting cancer
epidemiology studies is the length of time between exposure and effect.
Higher quality studies have adequately controlled for confounding and
have limited the potential for exposure misclassification, for example,
using DBP levels in drinking water as the exposure metric as opposed to
type of source water. Study design considerations for interpreting
cancer epidemiology data include sufficient follow-up time to detect
disease occurrence, adequate sample size, valid ascertainment of cause
of the cancer, and reduction of potential selection bias in case-
control and cohort studies (by having comparable cases and controls and
by limiting loss to follow-up). Epidemiology studies provide extremely
useful information on human exposure to chlorinated water, which
complement single chemical, high dose animal data.
In the Stage 1 DBPR, EPA concluded that the epidemiological
evidence suggested a potential increased risk for bladder cancer. Some
key studies EPA considered for Stage 1 include Cantor et al. (1998),
Doyle et al. (1997), Freedman et al. (1997), King and Marrett (1996),
McGeehin et al. (1993), Cantor et al. (1987), and Cantor et al. (1985).
Several studies published since the Stage 1 DBPR continue to support an
association between increased risk of bladder cancer and exposure to
chlorinated surface water (Chevrier et al. 2004; Koivusalo et al. 1998;
Yang et al. 1998). One study found no effects on a biomarker of
genotoxicity in urinary bladder cells from TTHM exposure (Ranmuthugala
et al. 2003). Epidemiological reviews and meta-analyses generally
support the possibility of an association between chlorinated water or
THMs and bladder cancer (Villanueva et al. 2004; Villanueva et al.
2003; Villanueva et al. 2001; Mills et al. 1998). The World Health
Organization (WHO 2000) found data inconclusive or insufficient to
determine causality between chlorinated water and any health endpoint,
although they concluded that the evidence is better for bladder cancer
than for other cancers.
In the Stage 1 DBPR, EPA concluded that early studies suggested a
small possible increase in rectal and colon cancers from exposure to
chlorinated surface waters. The database of studies on colon and rectal
cancers continues to support a possible association, but evidence
remains mixed. For colon cancer, one newer study supports the evidence
of an association (King et al. 2000a) while others showed inconsistent
findings (Hildesheim et al. 1998; Yang et al. 1998). Rectal cancer
studies are also mixed. Hildesheim et al. (1998) and Yang et al. (1998)
support an association with rectal cancer while King et al. (2000a) did
not. A review of colon and rectal cancer concluded evidence was
inconclusive but that there was a stronger association for rectal
cancer and chlorination DBPs than for colon cancer (Mills et al. 1998).
The WHO (2000) review reported that studies showed weak to moderate
associations with colon and rectal cancers and chlorinated surface
water or THMs but that evidence is inadequate to evaluate these
associations.
Recent studies on kidney, brain, and lung cancers and DBP exposure
support a possible association (kidney: Yang et al. 1998, Koivusalo et
al. 1998; brain: Cantor et al. 1999; lung: Yang et al. 1998). However,
so few studies have examined these endpoints that definitive
conclusions cannot be made. Studies on leukemia found little or no
association with DBPs (Infante-Rivard et al. 2002; Infante-Rivard et
al. 2001). A recent study did not find an association between
pancreatic cancer and DBPs (Do et al. 2005). A study researching
multiple cancer endpoints found an association between THM exposure and
all cancers when grouped together (Vinceti et al. 2004). More details
on the cancer epidemiology studies since the Stage 1 DBPR are outlined
in Table II.D-1.
Table II.D-1.--Summary of Cancer Epidemiology Studies Reviewed for Stage 2 DBPR
----------------------------------------------------------------------------------------------------------------
Exposure(s) Outcome(s)
Study type studied measured Findings
----------------------------------------------------------------------------------------------------------------
Author(s)
Do et al. 2005................. Case-control Estimated Pancreatic cancer No association was
study in Canada, chlorinated found between
1994-1997. DBPs, pancreatic cancer and
chloroform, BDCM exposure to
concentrations. chlorinated DBPs,
chloroform, or BDCM.
Chevrier et al. 2004........... Case-control Compared THM Bladder cancer... A statistically
study in France, levels, duration significant decreased
1985-1987. of exposure, and risk of bladder
3 types of water cancer was found as
treatment duration of exposure
(ozonation, to ozonated water
chlorination, increased. This was
ozonation/ evident with and
chlorination). without adjustment
for other exposure
measures. A small
association was
detected for
increased bladder
cancer risk and
duration of exposure
to chlorinated
surface water and
with the estimated
THM content of the
water, achieving
statistical
significance only
when adjusted for
duration of ozonated
water exposures.
Effect modification
by gender was noted
in the adjusted
analyses.
[[Page 396]]
Vinceti et al. 2004............ Retrospective Standardized 15 cancers Mortality ratio from
cohort study in mortality ratios including colon, all cancers showed a
Italy, 1987-1999. from all causes rectum, and statistically
vs. cancer for bladder. significant small
consumers increase for males
drinking water consuming drinking
with high THMs. water with high THMs.
For females, an
increased mortality
ratio for all cancers
was seen but was not
statistically
significant. Stomach
cancer in men was the
only individual
cancer in which a
statistically
significant excess in
mortality was
detected for
