Current through February, 2024
(a)
Community water systems shall conduct monitoring to determine
compliance with the MCLs specified in section
11-20-3
in accordance with this section. Non-transient, non-community water systems
shall conduct monitoring to determine compliance with the MCLs specified in
section
11-20-3
in accordance with this section. Transient, non-community water systems shall
conduct monitoring to determine compliance with the nitrate and nitrite MCLs in
section
11-20-3
in accordance with this section. Monitoring shall be conducted as follows:
(1) Ground water systems shall take a minimum
of one sample at every entry point to the distribution system which is
representative of each well after treatment (hereafter called a sampling point)
beginning in the initial compliance period. The system shall take each sample
at the same sampling point unless conditions make another sampling point more
representative of each source or treatment plant.
(2) Surface water systems shall take a
minimum of one sample at every entry point to the distribution system after any
application of treatment or in the distribution system at a point which is
representative of each source after treatment (hereafter called a sampling
point) beginning in the initial compliance period. The system shall take each
sample at the same sampling point unless conditions make another sampling point
more representative of each source or treatment plant. Note: For purposes of
this paragraph, surface water systems include systems with a combination of
surface and ground sources.
(3) If
a system draws water from more than one source and the sources are combined
before distribution, the system must sample at an entry point to the
distribution system during periods of normal operating conditions (i.e., when
water is representative of all sources being used).
(4) The director may reduce the total number
of samples which must be analyzed by allowing the use of compositing. Composite
samples from a maximum of five samples are allowed, provided that the detection
limit of the method used for analysis is less than one-fifth of the MCL.
Compositing of samples must be done in the laboratory.
(A)
If the concentration in the composite sample is greater than or
equal to one-fifth of the MCL of any inorganic chemical, then a follow-up
sample must be taken within fourteen days at each sampling point included in
the composite. These samples must be analyzed for the contaminants which
exceeded one-fifth of the MCL in the composite sample. Detection limits for
each analytical method and MCLs for each inorganic contaminant are specified in
40 C.F.R.
§
141.23(a)(4)(i).
(B) If the population served by
the system is greater than 3,300 persons, then compositing may only be
permitted by the director at sampling points within a single system. In systems
serving less than or equal to 3,300 persons, the director may permit
compositing among different systems provided the five-sample limit is
maintained.
(C) If duplicates of
the original sample taken from each sampling point used in the composite are
available, the system may use these instead of resampling. The duplicates must
be analyzed and the results reported to the State within fourteen days of
collection.
(5) The
frequency of monitoring for asbestos shall be in accordance with subsection
(b); the frequency of monitoring for antimony, arsenic, barium, beryllium,
cadmium, chromium, cyanide, fluoride, mercury, nickel, selenium, and thallium
shall be in accordance with subsection (c); the frequency of monitoring for
nitrate shall be in accordance with subsection (d); and the frequency of
monitoring for nitrite shall be in accordance with subsection (e).
(b) The frequency of monitoring
conducted to determine compliance with the MCL for asbestos specified in
section
11-20-3(b)
shall be conducted as follows:
(1) Each
community and non-transient, non-community water system is required to monitor
for asbestos during the first three-year compliance period of each nine-year
compliance cycle beginning in the compliance period starting January 1,
1993.
(2) If the system believes it
is not vulnerable to either asbestos contamination in its source water or due
to corrosion of asbestos-cement pipe, or both, it may apply to the director for
a waiver of the monitoring requirement in paragraph (1). If the director grants
the waiver, the system is not required to monitor.
(3) The director may grant a waiver based on
a consideration of the following factors:
(A)
Potential asbestos contamination of the water source; and
(B) The use of asbestos-cement pipe for
finished water distribution and the corrosive nature of the water.
(4) A waiver remains in effect
until the completion of the three-year compliance period. Systems not receiving
a waiver must monitor in accordance with the paragraph (1).
(5) A system vulnerable to asbestos
contamination due solely to corrosion of asbestos-cement pipe shall take one
sample at a tap served by asbestos-cement pipe and under conditions where
asbestos contamination is most likely to occur.
(6) A system vulnerable to asbestos
contamination due solely to source water shall monitor in accordance with the
provision of subsection (a).
(7) A
system vulnerable to asbestos contamination due both to its source water supply
and corrosion of asbestos-cement pipe shall take one sample at a tap served by
asbestos-cement pipe and under conditions where asbestos contamination is most
likely to occur.
(8) A system which
exceeds the MCLs as determined in subsection (i) shall monitor quarterly
beginning in the next quarter after the violation occurred.
(9) The director may decrease the quarterly
monitoring requirement to the frequency specified in paragraph (1) provided the
director has determined that the system is reliably and consistently below the
MCL. In no case shall the director make this determination unless a ground
water system takes a minimum of two quarterly samples and a surface (or
combined surface and ground) water system takes a minimum of four quarterly
samples.
(10) If monitoring data
collected after January 1, 1990 are generally consistent with the requirements
of this subsection, then the director may allow systems to use that data to
satisfy the monitoring requirement for the initial compliance period beginning
January 1, 1993.
(c) The
frequency of monitoring conducted to determine compliance with the MCLs in
section
11-20-3
for antimony, arsenic, barium, beryllium, cadmium, chromium, cyanide, fluoride,
mercury, nickel, selenium, and thallium shall be as follows:
(1) Ground water systems shall take one
sample at each sampling point during each compliance period. Surface water
systems (or combined surface and ground) shall take one sample annually at each
sampling point.
(2) The system may
apply to the director for a waiver from the monitoring frequencies specified in
paragraph (1). States may grant a public water system a waiver for monitoring
of cyanide, provided that the director determines that the system is not
vulnerable due to lack of any industrial source of cyanide.
(3) A condition of the waiver shall require
that a system shall take a minimum of one sample while the waiver is effective.
The term during which the waiver is effective shall not exceed one compliance
cycle (i.e., nine years).
(4) The
director may grant a waiver provided surface water systems have monitored
annually for at least three years and ground water systems have conducted a
minimum of three rounds of monitoring. (At least one sample shall have been
taken since January 1, 1990). Both surface and ground water systems shall
demonstrate that all previous analytical results were less than the MCL.
Systems that use a new water source are not eligible for a waiver until three
rounds of monitoring from the new source have been completed.
(5) In determining the appropriate reduced
monitoring frequency, the director shall consider:
(A)
Reported concentrations from all previous monitoring;
(B) The degree of variation in reported
concentrations; and
(C) Other
factors which may affect contaminant concentrations such as changes in ground
water pumping rates, changes in the system's configuration, changes in the
system's operating procedures, or changes in stream flows or characteristics.
(6) A decision by the
director to grant a waiver shall be made in writing and shall set forth the
basis for the determination. The determination may be initiated by the director
or upon an application by the public water system. The public water system
shall specify the basis for its request. The director shall review and, where
appropriate, revise its determination of the appropriate monitoring frequency
when the system submits new monitoring data or when other data relevant to the
system's appropriate monitoring frequency become available.
(7) Systems which exceed the MCLs as
calculated in subsection (i) shall monitor quarterly beginning in the next
quarter after the violation occurred.
(8)
The director may decrease the quarterly monitoring requirement to
the frequencies specified in paragraphs (1) and (2) provided the director has
determined that the system is reliably and consistently below the MCL. In no
case shall the director make this determination unless a ground water system
takes a minimum of two quarterly samples and a surface water system takes a
minimum of four quarterly samples.
(9)
All new systems or systems that use a new source of water that
begin operation after January 22, 2004 must demonstrate compliance with the MCL
within a period of time specified by the director. The system must also comply
with the initial sampling frequencies specified by the director to ensure that
a system can demonstrate compliance with the MCL. Routine and increased
monitoring frequencies shall be conducted in accordance with the requirements
of this section.
(d)
All public water systems (community and non-community systems) shall monitor to
determine compliance with the MCL for nitrate in section
11-20-3.
(1) Community and non-transient,
non-community water systems served by ground water systems shall monitor
annually beginning January 1, 1993; systems served by surface water shall
monitor quarterly beginning January 1, 1993.
(2)
For community and non-transient, non-community water systems, the
repeat monitoring frequency for ground water systems shall be quarterly for at
least one year following any one sample in which the concentration is greater
than or equal to 50 per cent of the MCL. The director may allow a ground water
system to reduce the sampling frequency to annually after four consecutive
quarterly samples are reliably and consistently less than the MCL.
(3) For community and non-transient,
non-community water systems, the director may allow a surface water system to
reduce the sampling frequency to annually if all analytical results from four
consecutive quarters are less than 50 per cent of the MCL. A surface water
system shall return to quarterly monitoring if any one sample is greater than
or equal to 50 per cent of the MCL.
(4)
Each transient non-community water system shall monitor annually
beginning January 1, 1993.
(5)
After the initial round of quarterly sampling is completed, each community and
non-transient non-community system which is monitoring annually shall take
subsequent samples during the quarter(s) which previously resulted in the
highest analytical result.
(e)
All public water systems (community and non-community systems)
shall monitor to determine compliance with the MCL for nitrite in section
11-20-3(b).
(1) All public water systems shall take one
sample at each sampling point in the compliance period beginning January 1,
1993 and ending December 31, 1995.
(2) After the initial sample, systems where
an analytical result for nitrite is less than 50 per cent of the MCL shall
monitor at the frequency specified by the director.
(3) For community and non-community water
systems, the repeat monitoring frequency for any water system shall be
quarterly for at least one year following any one sample in which the
concentration is greater than or equal to 50 per cent of the MCL. The director
may allow a system to reduce the sampling frequency to annually after
determining the system is reliably and consistently less than the
MCL.
(4) Systems which are
monitoring annually shall take each subsequent sample during the quarter(s)
which previously resulted in the highest analytical result.
(f) Confirmation samples:
(1) Where the results of sampling for
asbestos, antimony, arsenic, barium, beryllium, cadmium, chromium, cyanide,
fluoride, mercury, nickel, selenium, or thallium indicate an exceedance of the
MCL, the director may require that one additional sample be collected as soon
as possible after the initial sample was taken (but not to exceed two weeks) at
the same sampling point.
(2) Where
nitrate or nitrite sampling results indicate an exceedance of the MCL, the
system shall take a confirmation sample within twenty-four hours of the
system's receipt of notification of the analytical results of the first sample.
Systems unable to comply with the twenty-four hour sampling requirement must
immediately notify the consumers served by the area served by the public water
system in accordance with section
11-20-18(b)
and meet other Tier 1 public notification requirements under section
11-20-18.
Systems exercising this option must take and analyze a confirmation sample
within two weeks of notification of the analytical results of the first
sample.
(3) If a director-required
confirmation sample is taken for any contaminant, then the results of the
initial and confirmation sample shall be averaged. The resulting average shall
be used to determine the system's compliance in accordance with subsection (i).
The director has the discretion to delete results of obvious sampling
errors.
(g) The director
may require more frequent monitoring than specified in subsections (b), (c),
(d), and (e) or may require confirmation samples for positive and negative
results at his or her discretion.
(h)
Systems may apply to the director to conduct more frequent
monitoring than the minimum monitoring frequencies specified in this section.
(i) Compliance with section
11-20-3
shall be determined based on the analytical result(s) obtained at each sampling
point.
(1) For systems which are conducting
monitoring at a frequency greater than annual, compliance with the MCLs for
antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide,
fluoride, mercury, nickel, selenium, or thallium is determined by a running
annual average at any sampling point. If the average at any sampling point is
greater than the MCL, then the system is out of compliance. If any one sample
would cause the annual average to exceed the MCL, then the system is out of
compliance immediately. Any sample below the method detection limit shall be
calculated at zero for the purpose of determining the annual average. If a
system fails to collect the required number of samples, compliance (average
concentration) will be based on the total number of samples collected.
(2) For systems which are
monitoring annually, or less frequently, the system is out of compliance with
the MCLs for asbestos, antimony, arsenic, barium, beryllium, cadmium, chromium,
cyanide, fluoride, mercury, nickel, selenium, or thallium if the level of a
contaminant at any sampling point is greater than the MCL. If a confirmation
sample is required by the director, the determination of compliance will be
based on the annual average of the initial MCL
exceedance and any State-required confirmation samples. If a system fails to
collect the required number of samples, compliance (average concentration) will
be based on the total number of samples collected.
(3) Compliance with the MCLs for nitrate and
nitrite is determined based on one sample if the levels of these contaminants
are below the MCLs. If the levels of nitrate, nitrite, or both, exceed the MCLs
in the initial sample, a confirmation sample is required in accordance with
subsection (f)(2), and compliance shall be determined based on the average of
the initial and confirmation samples.
(4)
Arsenic sampling results will be reported to the nearest 0.001
mg/L.
(j) Each public
water system shall monitor at the time designated by the director during each
compliance period.
(k) Inorganic
analysis:
(1) Analysis for the following
contaminants shall be conducted in accordance with the methods in
40 C.F.R.
§
141.23(k)(1), or the
alternative methods listed in Appendix A to subpart C of part 141, or their
equivalent as determined by EPA. Criteria for analyzing arsenic, barium,
beryllium, cadmium, calcium, chromium, copper, lead, nickel, selenium, sodium,
and thallium with digestion or directly without digestion, and other analytical
test procedures are 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, OH 45242-0419 or
http://www.epa.gov/nscep/.
(2) Sample collection for antimony, arsenic,
asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury,
nickel, nitrate, nitrite, selenium, and thallium under this section shall be
conducted using the sample preservation, container, and maximum holding time
procedures specified in
40 C.F.R.
§
141.23(k)(2).
(3) Analysis under this section shall only be
conducted by laboratories that have been certified by EPA or the director.
Laboratories may conduct sample analysis under provisional certification until
January 1, 1996. To receive certification to conduct analyses for antimony,
arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride,
mercury, nickel, nitrate, nitrite, selenium, and thallium, the laboratory must:
(A) Analyze Performance Evaluation samples
which include those substances provided by EPA; the director; or by a third
party (with the approval of the director or EPA) at least once a year.
(B) For each contaminant that has
been included in the PE sample and for each method for which the laboratory
desires certification, achieve quantitative results on the analyses that are
within the acceptance limits specified in
40 C.F.R.
§
141.23(k)(3)(ii).
(l) Analyses
for the purpose of determining compliance with section
11-20-3
shall be conducted using the requirements specified in subsections (l) through
(q).
(1) Analyses for all community water
systems utilizing surface water sources shall be completed by June 24, 1978.
These analyses shall be repeated at yearly intervals.
(2) Analyses for all community water systems
utilizing only ground water sources shall be completed by June 24, 1979. These
analyses shall be repeated at three-year intervals.
(3) For non-community water systems, whether
supplied by surface or ground sources, analyses for nitrate shall be completed
by December 24, 1980. These analyses shall be repeated at intervals determined
by the director.
(4) The director
has the authority to determine compliance or initiate enforcement action based
upon analytical results and other information compiled by their sanctioned
representatives and agencies.
(m)
If the result of an analysis made under subsection (l) indicates
that the level of any contaminant listed in section
11-20-3
exceeds the MCL, the supplier of the water shall report to the director within
seven days and initiate three additional analyses at the same sampling point
within one month.
(n) When the
average of four analyses made pursuant to subsection (m) rounded to the same
number of significant figures as the MCL for the substance in question, exceeds
the MCL, the supplier of water shall notify the director pursuant to section
11-20-17
and give notice to the public pursuant to section
11-20-18.
Monitoring after public notification shall be at a frequency designated by the
director and shall continue until the MCL has not been exceeded in two
successive samples or until a monitoring schedule as a condition to a variance,
exemption, or enforcement action shall become effective.
(o) The provisions of subsections (m) and
(n) notwithstanding, compliance with the MCL for nitrate shall be determined on
the basis of the mean of two analyses. When a level exceeding the MCL for
nitrate is found, a second analysis shall be initiated within twenty-four
hours, and if the mean of the two analyses exceeds the MCL, the supplier of
water shall report his findings to the director pursuant to section
11-20-17
and shall notify the public pursuant to section
11-20-18.
(p) For the initial analyses
required by subsection (l)(1),(2), or (3), data for surface waters acquired
within one year prior to the effective date and data for ground waters acquired
within three years prior to the effective date of this part may be substituted
at the discretion of the director.