Current through February, 2024
(b) Repeat monitoring.
(1) If a routine sample is total
coliform-positive, the supplier of water shall collect a set of repeat samples
within twenty-four hours of being notified of the positive result. The supplier
who collects more than one routine sample per month shall collect no fewer than
three repeat samples for each total coliform-positive sample found. A supplier
who normally collects one routine sample per month shall collect no fewer than
four repeat samples for each total coliform-positive sample found. The director
may extend the twenty-four hour limit on a case-by-case basis if the supplier
has a logistical problem in collecting or analyzing the repeat samples within
twenty-four hours that is beyond the supplier's control. In the case of an
extension, the director shall specify how much time the supplier has to collect
the repeat samples.
(2) The
supplier shall collect at least one repeat sample from the sampling tap where
the original total coliform-positive sample was taken, and at least one repeat
sample at a tap within five service connections upstream and at least one
repeat sample at a tap within five service connections downstream of the
original sampling site. If a total coliform-positive sample is at the end of
the distribution system, or one away from the end of the distribution system,
the director may waive the requirement to collect at least one repeat sample
upstream or downstream of the original sampling site. However, the supplier
shall collect the required number of repeat samples. A system with a single
service connection may take all repeats from the same sample tap.
(3) The supplier shall collect all repeat
samples on the same day.
(4) If one
or more repeat samples in the set is total coliform-positive, the supplier
shall collect an additional set of repeat samples in the manner specified in
paragraphs (1) to (3) unless the supplier determines the MCL for total
coliforms in section
11-20-6
has been exceeded and notifies the director. The additional samples shall be
collected within twenty-four hours of being notified of the positive result,
unless the director extends the limit as provided in paragraph (1). The
supplier shall repeat this process until either total coliforms are not
detected in one complete set of repeat samples or the supplier determines that
the MCL for total coliforms in section
11-20-6
has been exceeded and notifies the director.
(5)
If a supplier collecting fewer than five routine samples per
month has one or more total coliform-positive samples and the director does not
invalidate the sample(s) under subsection (c), the supplier shall collect at
least five routine samples during the next month the system provides water to
the public.
(6) Results of all
routine and repeat samples not invalidated by the director shall be included in
determining compliance with the MCL for total coliforms in section
11-20-6.
(c) Invalidation of total coliform
samples. A total coliform-positive sample invalidated under this subsection
does not count towards meeting the minimum monitoring requirements of this
section.
(1) The director may invalidate a
total coliform-positive sample if one or more of the following are met:
(A) The laboratory establishes that improper
sample analysis caused the total coliform-positive result.
(B) The director, on the basis of the results
of repeat samples collected as required by subsection (b)(1) to (4) determines
that the total coliform-positive sample resulted from a domestic or other
non-distribution system plumbing problem. The director cannot invalidate a
sample on the basis of repeat sample results unless all repeat sample(s)
collected at the same tap as the original total coliform-positive sample are
also total coliform-positive, and all repeat samples collected within five
service connections of the original tap are total coliform-negative (e.g., the
director cannot invalidate a total coliform-positive sample on the basis of
repeat samples if all the repeat samples are total coliform-negative, or if the
public water system has only one service connection).
(C) The director has substantial grounds to
believe that a total coliform-positive result is due to a circumstance or
condition which does not reflect water quality in the distribution system. In
this case, the supplier shall still collect all repeat samples required under
subsection (b)(l) to (4), and use them to determine compliance with the MCL for
total coliforms in section
11-20-6.
To invalidate a total coliform-positive sample under this paragraph, the
decision with the rationale for the decision shall be documented in writing,
and approved and signed by the director. The director shall make this document
available to EPA and the public. The written documentation shall specify the
cause of the total coliform-positive sample, and what action the supplier has
taken, or will take, to correct this problem. The director may not invalidate a
total coliform-positive sample solely on the grounds that all repeat samples
are total coliform-negative.
(2) A
laboratory shall invalidate a total coliform sample (unless total coliforms are
detected) if the sample produces a turbid culture in the absence of gas
production using an analytical method where gas formation is examined (e.g.,
the Multiple-Tube Fermentation Technique), produces a turbid culture in the
absence of an acid reaction in the Presence-Absence (P-A) Coliform Test, or
exhibits confluent growth or produces colonies too numerous to count with an
analytical method using a membrane filter (e.g., Membrane Filter Technique). If
a laboratory invalidates a sample because of such interference, the supplier
shall collect another sample from the same location as the original sample
within twenty-four hours of being notified of the interference problem, and
have it analyzed for the presence of total coliforms. The supplier shall
continue to re-sample within twenty-four hours and have the samples analyzed
until it obtains a valid result. The director may waive the twenty-four hour
time limit on a case-by-case basis.
(e) Fecal coliforms/Escherichia coli (E.
coli) testing.
(1) If any routine or repeat
sample is total coliform-positive, the laboratory shall analyze the total
coliform-positive culture medium to determine if fecal coliforms or E. coli are
present.
(2) The director has the
discretion to allow a supplier of water, on a case-by-case basis, to forgo
fecal coliform or E. coli testing on a total coliform-positive sample if that
supplier classifies the total coliform-positive sample as fecal
coliform-positive or E. coli-positive. In the event the laboratory fails to
perform the required fecal coliform or E. coli analysis, the total
coliform-positive sample will be classified as fecal coliform positive or E.
coli-positive.
(f)
Response to positive result.
(1) The supplier
shall report the positive result for total coliforms or fecal coliforms or E.
coli to the director by 4:00 p.m. of the day that the supplier is notified of
the positive result. However, if the supplier is notified of the result after
4:00 p.m., then the supplier shall notify the director as soon as possible but
no later than 10:00 a.m. of the next department business day.
(2) When a public water system has a fecal
coliform- positive or E. coli-positive result, the supplier shall issue a boil
water notice to all affected consumers.
(A)
The boil water order shall be issued no later than twenty-four hours after the
system has been notified of the positive fecal coliform or positive E. coli
result. The boil water notice shall be in effect until negative total coliform
results are obtained from the affected tap and from all other required repeat
sample sites.
(B) The boil water
notice shall not be required if all repeat samples collected are total
coliform-negative, and these results are received within twenty-four hours of
the fecal-positive or E. coli-positive result.
(g) Response to violation.
(1) When a public water system has exceeded
the MCL for total coliforms as set forth in section
11-20-6,
the supplier shall report the violation to the director no later than the end
of the next business day after learning of the violation, and notify the public
in accordance with section
11-20-18.
(2) A supplier who has failed to
comply with a coliform monitoring requirement, including the sanitary survey
requirement, shall report the monitoring violation to the director within ten
days after the supplier discovers the violation, and notify the public in
accordance with section
11-20-18.
(i) The provisions of subsections (b), (c),
(e), (f), and (g) are applicable until all required repeat monitoring under
subsection (b) and fecal coliform or E. coli testing under
subsection (e) that was initiated by a total coliform-positive sample taken
before April 1, 2016 is completed, as well as reporting, recordkeeping, public
notification, and consumer confidence report requirements associated with that
monitoring and testing. Beginning April 1, 2016, the provisions of section
11-20-9.1
are applicable, with systems required to begin regular monitoring at the same
frequency as the system-specific frequency required on March 31,
2016.