Current through February, 2024
(a) General requirements
This section, also known as the Surface Water Treatment Rule
(SWTR), establishes criteria under which filtration is required as treatment
for public water systems supplied by either a surface water source or by a
ground water source under the direct influence of surface water (GWUDI). In
addition, these rules establish treatment requirements in lieu of MCLs for the
following contaminants: Giardia lamblia, viruses, heterotrophic plate count
(HPC) bacteria, Legionella, and turbidity.
(1)
Each public water system with a surface water source or a GWUDI
source shall provide treatment of that source water by installing and properly
operating water treatment processes which reliably achieve at least:
(A) A total of 99.9 per cent (3-log) removal
and/or inactivation of Giardia lamblia cysts between a point where the raw
water is not subject to recontamination by surface water runoff and a point
downstream before or at the first customer; and
(B) A total of 99.99 per cent (4-log) removal
and/or inactivation of viruses between a point where the raw water is not
subject to recontamination by surface water runoff and a point downstream
before or at the first customer.
(2)
A public water system using a surface water source or a GWUDI
source shall meet the requirements of this section if it meets the disinfection
requirements in subsection (b) and the filtration requirements in subsection
(c).
(3) Each public water system
using a surface water source or a GWUDI source shall be operated by qualified
personnel who meet the requirements specified by the director to minimize risk
to human health or welfare.
(4)
Water purveyors with a surface water or GWUDI source shall implement the
requirements of the 'Surface Water Treatment Rule Administrative Manual" dated
January 1, 2002. Copies of the administrative manual are available upon request
from the safe drinking water branch office in Honolulu, or the district health
offices on Kauai, Maui, and Hawaii.
(5)
In addition to complying with the requirements in this section,
systems must also comply with the requirements in section
11-20-46.1.
(b) Disinfection. A public water system that
uses a surface water source or a GWUDI source shall comply, before filtration
is installed, with any interim disinfection requirements the director deems
necessary to protect human health and welfare. A system that uses a surface
water source or a GWUDI source shall provide the disinfection treatment
specified in this subsection beginning June 29, 1993, or beginning when
filtration is installed, whichever is later. Each public water system that
provides filtration treatment shall provide disinfection treatment as follows:
(1) The disinfection treatment shall be
sufficient to ensure that the total treatment processes of that system achieve
at least a total of 99.9 per cent (3-log) inactivation of Giardia lamblia cysts
and at least a total of 99.99 per cent (4-log) inactivation of viruses, as
determined by the director. Each public water system shall prove that it is
meeting the previous disinfection criteria by determining CTs and total
inactivation ratios of 1.0 or greater and reporting these data to the director
on a monthly basis;
(2) The
residual disinfectant concentration in the water entering the distribution
system, measured as specified in subsections (d)(1)(B) and (d)(2)(B)(ii),
cannot be less than 0.2 mg/l for more than four hours; and
(3) The residual disinfectant concentration
in the distribution system, measured as total chlorine, combined chlorine, or
chlorine dioxide, as specified in subsection (d)(1)(B), cannot be undetectable
in more than five per cent of the samples each month, for any two consecutive
months that the system serves water to the public. Water in the distribution
system with a heterotrophic bacteria concentration greater than 500/ml,
measured as HPC as specified in subsection (d)(1)(A), is deemed to have an
undetectable disinfectant residual for purposes of determining compliance with
this requirement. Thus, the value "v" in the formula given in subsection
(e)(2)(B)(iv) cannot exceed five per cent in one month, for any two consecutive
months.
(c) Filtration.
A public water system that uses a surface water source or a GWUDI source shall
provide treatment consisting of both disinfection, as specified in subsection
(b), and filtration treatment which complies with the requirements of
paragraphs (1) and (2) by June 29, 1993.
(1)
Except where specified in section
11-20-46.1(c),
the turbidity level of representative samples of a system's filtered water
shall at no time exceed 5 NTU, measured as specified in subsections (d)(1)(A)
and (d)(2)(B)(i).
(2) The
turbidity level of representative samples of a system's filtered water shall be
less than or equal to the following values in at least ninety-five per cent of
the measurements taken each month as specified in subsections (d)(1)(A) and
(d)(2)(B)(i).
(A) Conventional filtration
treatment or direct filtration. 0.5 NTU, measured as specified in subsections
(d)(1)(A) and (d)(2)(B)(i).
(i) Beginning
January 1, 2002, systems serving at least 10,000 people must meet the turbidity
requirements in section
11-20-46.1(c)(1).
(ii) Beginning January 1, 2005,
systems serving fewer than 10,000 people must meet the turbidity requirements
in section
11-20-46.1(c)(1).
(B) Slow sand filtration. 1
NTU.
(C) Diatomaceous earth
filtration. 1 NTU.
(D) Other
filtration technologies. A public water system may use a filtration technology
not listed in subparagraphs (A) to (C) if the supplier demonstrates to the
director, using pilot plant studies or other means, that the alternative
filtration technology, in combination with disinfection treatment meeting the
requirements of subsection (b), consistently achieves at least a total of 99.9
per cent removal and/or inactivation of Giardia lamblia cysts and at least a
total of 99.99 per cent removal and/or inactivation of viruses. For a system
that makes this demonstration, the requirements for subparagraph A apply.
Beginning January 1, 2002, systems serving at least 10,000 people must meet the
requirements for other filtration technologies in section
11-20-46.1(c)(2).
Beginning January 1, 2005, systems serving fewer than 10,000 people must meet
the requirements for other filtration technologies in section
11-20-46.1(c)(2).
(d)
Analytical and monitoring requirements.
(1)
Analytical requirements. Only the analytical method(s) specified in this
paragraph, or otherwise approved by EPA, may be used to demonstrate compliance
with the requirements of subsections (b) and (c). Measurements for pH,
temperature, turbidity, and residual disinfectant concentrations shall be
conducted by a party approved by the director. Measurements for total
coliforms, fecal coliforms or E. coli, and HPC shall be conducted by a
laboratory certified by the director or EPA to do such analysis. Until
laboratory certification criteria are developed for the analysis of HPC and
fecal coliforms or E. coli, any laboratory certified for total coliform
analysis by EPA is deemed certified for HPC and fecal coliform or E. coli
analysis. The following procedures shall be performed in accordance with the
publications listed in the following subparagraphs.
(A) Public water systems must conduct
analysis of pH and temperature in accordance with one of the methods listed in
40 C.F.R.
§
141.23(k)(1). Public
water systems must conduct analyses of total coliforms, fecal coliforms or E.
coli, heterotrophic bacteria, and turbidity in accordance with the analytical
methods in
40 C.F.R. §
141.74(a)(1) or alternative
methods listed in Appendix A to Title 40 Code of Federal Regulations, Part 141,
Subpart C, and by using analytical test procedures contained in
Technical Notes on Drinking Water Methods, EPA-600/R-94-173,
October 1994. This document is available from the National Service Center for
Environmental Publications (NSCEP), P.O. Box 42419, Cincinnati, Ohio 45242-0419
or
http://www.epa.gov/nscep/.
(B) Public water systems must measure
residual disinfectant concentrations with one of the analytical methods in
40 C.F.R. §
141.74(a)(2) or alternative
methods listed in Appendix A to Title 40 Code of Federal Regulations, Part 141,
Subpart C. If approved by the director, residual disinfectant concentrations
for free chlorine and combined chlorine also may be measured by using DPD
colorimetric test kits. Free and total chlorine residuals may be measured
continuously by adapting a specified chlorine residual method for use with a
continuous monitoring instrument provided the chemistry, accuracy, and
precision remain the same. Instruments used for continuous monitoring must be
calibrated with a grab sample measurement at least every five days, or with a
protocol approved by the director.
(2) Monitoring requirements.
(A) A public water system that uses a surface
water source or a GWUDI source shall comply with any interim reporting
requirements, as specified by the director to minimize risk to human health or
welfare, until filtration is in place.
(B) A public water system that uses a surface
water source or a GWUDI source and provides filtration treatment shall monitor
in accordance with this paragraph beginning June 29, 1993, or when filtration
is installed, whichever is later.
(i)
Turbidity measurements as required by subsection (c) shall be performed on
representative samples of the system's filtered water at least every four hours
that the system serves water to the public. A supplier may substitute
continuous turbidity monitoring for grab sample monitoring if the supplier
validates the continuous measurement for accuracy on a regular basis using a
protocol approved by the director.
(ii)
The residual disinfectant concentration of the water entering the
distribution system shall be monitored continuously, and the lowest value shall
be recorded each day, except that if there is a failure in the continuous
monitoring equipment, grab sampling every four hours may be conducted in lieu
of continuous monitoring, but for no more than five working days following the
failure of the equipment. If at any time the residual disinfectant
concentration falls below 0.2 mg/l in a system using grab sampling in lieu of
continuous monitoring, the supplier shall take a grab sample every four hours
until the residual disinfectant concentration is equal to or greater than 0.2
mg/l.
(iii) Beginning April 1,
2016, HPC must be measured at least at the same points in the distribution
system and at the same time as total coliforms are sampled, as specified in
sections
11-20-9.1(d)
and (e). The director may allow a public water system which uses both a surface
water source or a GWUDI source, and a ground water source to take HPC samples
at points other than the total coliform sampling points if the director
determines that such points are more representative of treated (disinfected)
water quality within the distribution system. Residual disinfectant
concentration should also be measured for operational control.
(e) Reporting
and recordkeeping requirements.
(1) A public
water system that uses a surface water source or a GWUDI source shall comply
with any interim reporting requirements, as specified by the director to
minimize risk to human health and welfare, until filtration is in
place.
(2) When a public water
system that uses a surface water source or a GWUDI source and provides
filtration treatment, the supplier shall report monthly to the director the
information specified in this paragraph beginning June 29, 1993, or when
filtration is installed, whichever is later.
(A)
Turbidity measurements as required by subsection (d)(2)(B)(i)
shall be reported within ten days after the end of each month the system serves
water to the public. Information that shall be reported includes:
(i) The total number of filtered water
turbidity measurements taken during the month.
(ii) The number and percentage of filtered
water turbidity measurements taken during the month which are less than or
equal to the turbidity limits specified in subsection (c) for the filtration
technology being used.
(iii) The
date and value of any turbidity measurements taken during the month which
exceed 5 NTU.
(B)
Disinfection information specified in subsection (d)(2) shall be reported to
the director within ten days after the end of each month the system serves
water to the public. Information that shall be reported includes:
(i) For each day, the lowest measured
residual disinfectant concentration in mg/l in water entering the distribution
system.
(ii) The date and duration
of each period when the residual disinfectant concentration in water entering
the distribution system fell below 0.2 mg/l and when the director was notified
of the occurrence.
(iii) The
following information on the samples taken in the distribution system in
conjunction with total coliform monitoring pursuant to subsection (b): the
number of routine total coliform samples collected and the number of instances
in which HPC is more than 500 per milliliter.
(iv) For the current and previous month the
system serves water to the public, the value of "V" in the following formula:
V = b X 100 / a
where
a = the number of routine total coliform samples
collected,
b = the number of instances in which HPC is more than 500 per
milliliter.
(C)
(i) Each supplier, upon discovering that a
waterborne disease outbreak potentially attributable to that water system has
occurred, must report that occurrence to the director as soon as possible, but
no later than by the end of the next business day.
(ii) If at any time the turbidity exceeds 5
NTU, the system must consult with the State as soon as practical, but no later
than 24 hours after the exceedance is known, in accordance with the public
notification requirements under section
11-20-18(c)(2)(C).
(iii) If at any time the disinfectant
residual falls below 0.2 mg/l in the water entering the distribution system,
the supplier must notify the director as soon as possible, but no later than by
the end of the next business day. The supplier also must notify the director by
the end of the next business day whether or not the residual was restored to at
least 0.2 mg/l within four hours.
(f) Recycle provisions.
(1) Applicability. All public water systems
supplied by a surface water source or a GWUDI source that employ conventional
filtration or direct filtration treatment and that recycle spent filter
backwash water, thickener supernatant, or liquids from dewatering processes
must meet the requirements in paragraphs (2) through (4).
(2) Reporting. A system must notify the
director in writing by December 8, 2003, if the system recycles spent filter
backwash water, thickener supernatant, or liquids from dewatering processes.
New plants shall be given 15 months from the startup date approved by the
director to report the information required under this subsection. This
notification must include, at a minimum, the information specified in
subparagraphs (A) and (B).
(A) A plant
schematic showing the origin of all flows which are recycled (including, but
not limited to, spent filter backwash water, thickener supernatant, and liquids
from dewatering processes), the hydraulic conveyance used to transport them,
and the location where they are reintroduced back into the treatment plant.
(B) Typical recycle flow in
gallons per minute (gpm), the highest observed plant flow experienced in the
previous year (gpm), design flow for the treatment plant (gpm), and
State-approved operating capacity for the plant where the director has made
such determinations.
(3)
Treatment technique requirement. Any system that recycles spent
filter backwash water, thickener supernatant, or liquids from dewatering
processes must return these flows through the processes of a system's existing
conventional or direct filtration system as defined in section
11-20-2
or at an alternate location approved by the director by June 8, 2004. If
capital improvements are required to modify the recycle location to meet this
requirement, all capital improvements must be completed no later than June 8,
2006. New plants shall return these recycle flows through the processes of a
system's conventional or direct filtration system or at an alternate location
approved by the director.
(4)
Recordkeeping. The system must collect and retain on file recycle flow
information specified in subparagraphs (A) through (F) for review and
evaluation by the director beginning June 8, 2004.
(A)
Copy of the recycle notification and information submitted to the
director under paragraph (2).
(B)
List of all recycle flows and the frequency with which they are
returned.
(C) Average and maximum
backwash flow rate through the filters and the average and maximum duration of
the filter backwash process in minutes.
(D)
Typical filter run length and a written summary of how filter run
length is determined.
(E) The type
of treatment provided for the recycle flow.
(F)
Data on the physical dimensions of the equalization and/or
treatment units, typical and maximum hydraulic loading rates, type of chemicals
used and average dose and frequency of use, and frequency at which solids are
removed, if applicable.