(1) A public water supplier shall provide, as
a minimum, continuous filtration and disinfection for surface water and GUDI
sources. The treatment technique must provide at least 99.9% removal and
inactivation of
Giardia lamblia cysts, and at least 99.99%
removal and inactivation of enteric viruses. Beginning January 1, 2002, public
water suppliers serving 10,000 or more people shall provide at least 99%
removal of
Cryptosporidium oocysts. Beginning January 1, 2005,
public water suppliers serving fewer than 10,000 people shall provide at least
99% removal of
Cryptosporidium oocysts. The Department,
depending on source water quality conditions, may require additional treatment
as necessary to meet the requirements of this chapter and to protect the public
health.
(i) The filtration process shall meet
the following performance requirements:
(A)
Conventional or irect filtration.
(I) The filtered water turbidity shall be
less than or equal to .5 NTU in 95% of the measurements taken each month under
109.301(1) (relating to general monitoring requirements).
(II) The filtered water turbidity shall be
less than or equal to 2.0 NTU at all times, measured under
109.301(1).
(III) Beginning January
1, 2002, for public water systems serving 10,000 or more persons, the filtered
water turbidity shall meet the following criteria:
(-a-) Be less than or equal to 0.3 NTU in at
least 95% of the measurements taken each month under 109.301(1).
(-b-) Be less than or equal to 1 NTU at all
times, measured under 109.301(1).
(IV) Beginning January 1, 2005, for public
water systems serving fewer than 10,000 persons, the filtered water turbidity
shall meet the following criteria:
(-a-) Be
less than or equal to 0.3 NTU in at least 95% of the measurements taken each
month under 109.301(1).
(-b-) Be
less than or equal to 1 NTU at all times, measured under 109.301(1).
(B)
Slow sand or
diatomaceous earth filtration.
(I)
The filtered water turbidity shall be less than or equal to 1.0 NTU in 95% of
the measurements taken each month under 109.301(1).
(II) The filtered water turbidity shall be
less than or equal to 2.0 NTU at all times, measured under
109.301(1).
(C)
Membrane filtration.
(I)
Beginning August 20, 2019, for all public water systems, the filtered water
turbidity must be less than or equal to 0.15 NTU in at least 95% of the
measurements taken each month under 109.301(1).
(II) Beginning August 20, 2019, for all
public water systems, the filtered water turbidity must be less than or equal
to 1 NTU at all times, measured under 109.301(1).
(D)
Other filtration
technologies. The same performance criteria as those given for
conventional filtration and direct filtration in clause (A) shall be achieved
unless the Department specifies more stringent performance criteria based upon
onsite studies, including pilot plant studies, where appropriate.
(ii) The combined total effect of
disinfection processes utilized in a filtration plant shall:
(A) Achieve at least 1.0-log inactivation of
Giardia cysts and 3.0-log inactivation of viruses as demonstrated by
measurements taken under 109.301(1). Failure to maintain the minimum log
inactivation for more than 4 hours of operation constitutes a breakdown in
treatment.
(B) Provide a minimum
residual disinfectant concentration of 0.20 mg/L at the entry point as
demonstrated by measurements taken under 109.301(1). Failure to maintain the
minimum entry point residual disinfectant concentration for more than 4 hours
of operation is a treatment technique violation.
(iii) For an unfiltered surface water source
permitted for use prior to March 25, 1989, the public water supplier shall:
(A) Maintain a minimum residual disinfectant
concentration in the water delivered to the distribution system prior to the
first customer of 2.5 mg/L expressed as free chlorine or its equivalent as
approved by the Department. The residual disinfectant concentration shall be
demonstrated by measurements taken under 109.301(2).
(I) For a system using disinfectants other
than free chlorine, the water supplier shall maintain:
(-a-) A minimum concentration that provides,
in terms of CTs achieved, a level of protection equivalent to that provided by
2.5 mg/L free chlorine, as determined by the available contact time between the
point of application and the first customer, under peak flow
conditions.
(-b-) At least .2 mg/L
of disinfectant in the water delivered to the distribution system prior to the
first customer.
(II) For
a system with extended contact times, generally 60 minutes or more, between the
point of application and the first customer, the Department may allow the water
supplier to maintain a disinfectant residual concentration less than 2.5 mg/L
free chlorine or its equivalent if the CTs established by the EPA are
achieved.
(B) Provide
continuous filtration and disinfection in accordance with this paragraph
according to the following schedule:
(I) By
December 31, 1991, for a public water system that, prior to March 25, 1989, had
a waterborne disease outbreak or Giardia contamination in its surface water
source.
(II) Within 48 months after
the discovery of one of the following conditions, or by December 31, 1995,
whichever is earlier, for a public water system that experiences the condition
after March 25, 1989:
(-a-) A waterborne
disease outbreak.
(-b-) Giardia
contamination in its surface water source.
(-c-) A violation of the microbiological MCL,
the turbidity MCL or the monitoring or reporting requirements for the
microbiological MCL.
(-d-) A
violation of the source microbiological or turbidity monitoring requirements
under 109.301(2)(i) or the related reporting requirements.
(-e-) The source water fecal coliform
concentration exceeds 20/100 ml or the total coliform concentration exceeds
100/100 ml in a source water sample collected under §
109.301(2).
(-f-) The source water turbidity level
exceeds 5.0 NTU in a sample collected under §
109.301(2).
(-g-) The system fails to maintain a
continuous residual disinfectant concentration as required under this
sub-paragraph.
(III) By
December 31, 1995, for other public water systems not covered by subclause (I)
or (II).
(iv)
For an unfiltered surface water source which is subject to subparagraph
(iii)(B)(II) and (III), the public water supplier shall:
(A) Submit to the Department for approval a
feasibility study which specifies the means by which the supplier shall, by the
applicable deadline established in subpara-graph (iii)(B), meet the
requirements of this paragraph. The study shall identify the alternative which
best assures the long-term viability of the public water system to meet
drinking water standards. The study shall propose a schedule for completion of
work, including the design, financing, construction and operation of one of the
following alternatives:
(I) Permanent
filtration treatment facilities that meet the requirements of this
chapter.
(II) Abandonment of the
unfiltered surface water source and one of the following:
(-a-) Permanent interconnection with another
water supply which meets the requirements of this chapter.
(-b-) Permanent water treatment facilities,
utilizing groundwater as the source of supply, which meet the requirements of
this chapter.
(-c-) Provision for
adequate supply from existing sources which meets the requirements of this
chapter.
(B)
Submit the feasibility study according to the following schedule:
(I) By March 31, 1992, for a supplier which
prior to August 31, 1991, experienced a triggering event as specified in
subparagraph (iii)(B)(II).
(II) By
June 30, 1992, for a supplier which after August 31, 1991, but before January
1, 1992, experienced a triggering event as specified in subparagraph
(iii)(B)(II).
(III) By August 31,
1992, for other suppliers.
(C) Submit a full and complete permit
application for the means identified in the approved feasibility study by which
the supplier shall meet the requirements of this paragraph, according to the
following schedule:
(I) By the date set in
the approved feasibility study for a supplier which, prior to January 1, 1992,
experienced a triggering event as specified in subparagraph
(iii)(B)(II).
(II) By June 30,
1993, for a supplier subject to the requirements of subparagraph (iii)(B)(III),
except that a public water supplier serving fewer than 3,300 people may submit
its permit application by December 31, 1993.
(D) Initiate construction of the means
identified in the approved feasibility study by which the supplier shall meet
the requirements of this paragraph, according to the following schedule:
(I) By the date set in the approved
feasibility study for a supplier which, prior to January 1, 1992, experienced a
triggering event as specified in subparagraph (iii)(B)(II).
(II) By June 30, 1994, for a supplier subject
to the requirements of subparagraph (iii)(B)(III), except that a public water
supplier serving fewer than 3,300 people may initiate construction by December
31, 1994.
(E) Complete
construction and commence operation of the alternative identified in the
approved feasibility study by the dates specified in subparagraph
(iii)(B).
(v) The
requirements of subparagraph (iv) do not modify, repeal, suspend, supersede or
otherwise change the terms of a compliance schedule or deadline, established by
an existing compliance order, consent order and agreement, consent
adjudication, court order or consent decree. For purposes of this paragraph,
the term "existing" means a compliance order, consent order and agreement,
consent adjudication, court order or consent decree which was issued or dated
before December 14, 1991.
(vi) For
a source including springs, infiltration galleries, cribs or wells permitted
for use by the Department prior to May 16, 1992, and determined by the
Department to be a GUDI source, the public water supplier shall:
(A) Maintain a minimum residual disinfectant
concentration in the water delivered to the distribution system prior to the
first customer in accordance with subpara-graph (iii)(A).
(B) Provide continuous filtration and
disinfection in accordance with this paragraph within 48 months after the
Department determines the source of supply is a GUDI source.
(C) Submit to the Department for approval a
feasibility study within 1 year after the Department determines the source of
supply is a GUDI source. The feasibility study shall specify the means by which
the supplier shall, within the deadline established in clause (B), meet the
requirements of this paragraph and shall otherwise comply with subparagraph
(iv)(A).
(2) In
addition to meeting the requirements of paragraph (1), a public water supplier
using surface water or GUDI sources shall also comply with the requirements of,
and on the schedules in, Subchapter L (relating to long-term 2 enhanced surface
water treatment rule).
(3) A
community public water system shall provide continuous disinfection and comply
with Subchapter M (relating to additional requirements for groundwater sources)
for groundwater sources.
(4) Public
water systems shall conduct assessments in accordance with 109.705(b) (relating
to system evaluations and assessments) after meeting any of the triggers under
subparagraph (i) or (ii). Failure to conduct an assessment or complete a
corrective action in accordance with 109.705(b) is a treatment technique
violation requiring 1-hour reporting in accordance with 109.701(a)(3) (relating
to reporting and recordkeeping) and public notification in accordance with
109.409 (relating to Tier 2 public
notice-categories, timing and delivery of notice).
(i) A Level 1 assessment is triggered if any
of the following conditions occur:
(A) For
systems taking 40 samples or more per month under 109.301(3), the system
exceeds 5.0% total coliform-positive samples for the month.
(B) For systems taking fewer than 40 samples
per month under 109.301(3), the system has two or more total coliform-positive
samples in the same month.
(C) The
system fails to take every required check sample under 109.301(3) after any
single total coliform-positive sample.
(ii) A Level 2 assessment is triggered if any
of the following conditions occur:
(A) A
system fails to meet the
E. coli MCL as specified under
subsection (a)(2).
(B) A system
triggers another Level 1 assessment, as defined in subparagraph (i), within a
rolling 12-month period, unless the Department has determined a likely reason
that the samples that caused the first Level 1 assessment were total
coliform-positive and has established that the system has corrected the
problem.
(5)
Failure by a seasonal water system to complete the approved start-up procedure
prior to serving water to the public as required under 109.715 (relating to
seasonal systems) is a treatment technique violation requiring 1-hour reporting
in accordance with 109.701(a)(3) and public notification in accordance with
§ 109.409.
(6) Community water
systems using a chemical disinfectant or that deliver water that has been
treated with a chemical disinfectant shall comply with the minimum residual
disinfectant concentration specified in
109.710 (relating to disinfectant
residual in the distribution system).
(7) Nontransient noncommunity water systems
that have installed chemical disinfection and transient noncommunity water
systems that have installed chemical disinfection in accordance with paragraph
(1) or 109.1302(b) (relating to treatment technique requirements) shall comply
with the minimum residual disinfectant concentration specified in §
109.710.
