Current through Register Vol. 18, September 20, 2024
(1) The total
coliform monitoring frequency for all public water supply systems serving 1,000 or
fewer people is one sample/month.
(2)
The department adopts and incorporates by reference the table in
40 CFR
141.857(b), which sets forth
total coliform monitoring frequency requirements for all public water supply systems
serving more than 1,000 people.
(a) The minimum
monitoring frequency for total coliforms is based on the average daily population
served by the system during the month of peak use.
(3) Upon written request of the water supplier,
the department may reduce the required coliform sampling frequency for a
non-seasonal transient noncommunity water system that uses only ground water that is
not under the direct influence of surface water and serves a maximum daily
population of 1,000 persons or fewer to once in each calendar quarter.
(a) Before applying for quarterly monitoring, the
system must operate and sample coliform bacteria monthly for a minimum of 24
consecutive months;
(b) The
determination to reduce monitoring must be based upon the results of coliform
bacteria samples from the past 24 consecutive months of system operation, sanitary
surveys, and any other information that indicates quarterly sampling is adequate to
protect public health;
(c) A water
supplier, who is authorized to sample quarterly may continue to sample quarterly
unless triggered to return to monthly monitoring. The following will trigger monthly
monitoring, or more frequent monitoring pursuant to (4), the month following the
event:
(i) the system triggers a Level 2 assessment
or two Level 1 assessments under the provisions of
40 CFR
141.859 in a rolling 12-month period;
(ii) the system has an E. coli MCL
violation;
(iii) the system has a
coliform treatment technique violation;
(iv) the system has two 40 CFR Part 141, subpart
Y, monitoring violations or one subpart Y monitoring violation and one Level 1
assessment under the provisions of
40 CFR
141.859 in a rolling 12-month period for a system
on quarterly monitoring;
(v) constructing
or modifying a system or system components without prior department approval, in
violation of 75-6-112, MCA, and ARM
17.38.101;
(vi) determination that a source or distribution
system is vulnerable to contamination based upon the results of a sanitary survey,
sample analyses, technical investigations or other scientifically defensible
information; or
(vii) not maintaining or
operating a system in accordance with the requirements of this chapter when the
department determines that the violation may affect the microbiological quality of
the water supply system.
(d)
When monthly monitoring is triggered, the department shall provide written notice to
the system that monthly monitoring is required;
(e) Under extreme circumstances, for the purpose
of determining eligibility for remaining on or qualifying for quarterly monitoring,
the department may elect to not count monitoring violations under
40 CFR
141.860(c)(1) if the missed
sample is collected no later than the end of the monitoring period following the
monitoring period in which the sample was missed. The system must collect the
make-up sample in a different week than the routine sample for that monitoring
period and must collect the sample as soon as possible during the monitoring period.
This authority does not affect the provisions of
40 CFR
141.860(c)(1) and
141.861(a)(4);
(f) The system must continue monthly monitoring
until the following criteria have been met:
(i)
within the last 12 months, the system must have completed a sanitary survey or a
site visit by the department or a voluntary Level 2 assessment by a party approved
by the department, be free of sanitary defects, and have a protected water
source;
(ii) no MCL violations under
40 CFR
141.63, no monitoring violations under
40 CFR
141.21 or subpart Y, and no coliform treatment
technique trigger exceedances or treatment technique violations under subpart Y, for
a minimum of 12 months;
(iii) valid
samples that do not contain coliform bacteria have been taken for at least 12
consecutive months of system operation;
(iv) the department has approved all submitted
plans and specifications for system construction and modifications in accordance
with 75-6-112, MCA, and ARM
17.38.101;
(v) the identified sources of
contamination have been removed;
(vi)
appropriate improvements in maintenance and operation have been implemented;
and
(vii) the public water system
petitions the department and the petition is approved in
writing.
(g) Systems
collecting samples on a quarterly frequency must conduct additional routine
monitoring the month following one or more total coliform-positive samples (with or
without a Level 1 treatment technique trigger). Systems must collect at least three
routine samples during the next month. Systems may either collect samples at regular
time intervals throughout the month or may collect all required routine samples on a
single day if samples are taken from different sites. Systems must use the results
of additional routine samples in coliform treatment technique trigger calculations
under 40 CFR
141.859(a).
(4) The department may increase the required
sampling frequency of any public water supply system based upon sampling results or
other conditions that indicate a risk to the health of the water users. The
department shall provide the supplier with a written explanation of any revised
sampling requirements. A supplier shall implement any increase in sampling frequency
immediately upon receipt of written notice of the increase from the
department.
(5) The department adopts
and incorporates by reference the following, which set forth requirements for the
revised total coliform rule (RTCR):
(a)
40 CFR
141.851, except that the term "April 1, 2016" is
replaced with "February 18, 2017." This rule sets forth general requirements for the
RTCR;
(b)
40 CFR
141.852, which sets forth analytical methods and
laboratory certification requirements for coliform testing, except that, for the
purpose of this subchapter, the phrase "laboratory certified by the EPA or a primacy
State" means "approved laboratory" as defined in ARM
17.38.202;
(c)
40 CFR
141.853, except for subsection (a)(5)(ii) and
subsection (b). And except that the term "March 31, 2016" is replaced with "February
18, 2017." This rule sets forth general monitoring requirements for all
systems;
(d)
40 CFR
141.854(a)(1) through
141.854(a)(3), which
set forth general requirements for non-community water systems serving 1,000 or
fewer people using only ground water;
(e)
40 CFR
141.854(i)(1),
141.856(a)(4)(i), and
141.857(a)(4)(i),
except that the term "April 1, 2016" is replaced with "February 18, 2017." This rule
provides start-up procedure requirements for seasonal systems. The department may
exempt any seasonal system from some or all of the requirements for seasonal systems
if the entire distribution system remains pressurized during the entire period that
the system is not operating;
(f)
40 CFR
141.855(a), which sets forth
general requirements for community systems serving 1,000 or fewer people using only
ground water;
(g)
40 CFR
141.856(a)(1) through
141.856(a)(3) and
141.856(c), which set
forth general requirements for subpart H public water systems serving 1,000 or fewer
people;
(h)
40 CFR
141.857(a)(1) through
141.857(a)(3) and
141.857(c). This rule
sets forth general requirements for public water systems serving more than 1,000
people;
(i)
40 CFR
141.858, which sets forth repeat monitoring and E.
coli requirements, except for the following changes:
(i) the first sentence in 141.858(a)(1) is changed
to "If a sample taken under ARM
17.38.215(1) through
(3),
40 CFR
141.856(c), or
40 CFR
141.857(c), is total
coliform-positive, the system must collect a set of repeat samples within 24 hours
of being notified of the positive result."; and
(ii) 141.858(a)(5) is changed to "Results of all
routine and repeat samples taken under ARM 17.38.215, not invalidated by the State,
must be used to determine whether a coliform treatment technique trigger specified
in 40 CFR
141.859 has been exceeded.";
(j)
40 CFR
141.859, except for subsection (a)(2)(iii) and
subsection (b)(4)(ii). This rule sets forth requirements for coliform treatment
technique triggers and assessments for protection against potential fecal
contamination;
(k)
40 CFR
141.860, which sets forth requirements for
violations; and
(l)
40 CFR
141.861, which sets forth requirements for
reporting and recordkeeping.
(6) A special purpose sample, including a sample
taken to determine whether adequate disinfection has occurred after pipe placement
or repair, may not be taken from a part of the public water supply distribution
system that is actively serving the public and must not be used to determine
compliance with the RTCR. Repeat samples taken pursuant to
40 CFR
141.858 are not special purpose samples and must
be used to determine whether the coliform treatment technique trigger has been
exceeded.
(7) The department shall
perform a special monitoring evaluation during each sanitary survey of ground water
systems serving 1,000 or fewer people to review the status of the system, including
the distribution system, to determine whether the system is on an appropriate
monitoring schedule. After the department has performed the special monitoring
evaluation during each sanitary survey, the department may modify the system's
monitoring schedule, as necessary, or it may allow the system to stay on its
existing monitoring schedule, consistent with this rule. The department may not
allow systems to begin less frequent monitoring under the special monitoring
evaluation unless the system has already met the applicable criteria for less
frequent monitoring in (3)(b).
(8) A
supplier shall collect at least two samples that must be analyzed for coliform
bacteria from any new source of water supply to demonstrate compliance with this
subchapter before the source is connected to a public water supply system.
AUTH:
75-6-104, MCA; IMP:
75-6-104,
MCA
