| (1) Distribution coliform sample invalidation. The
executive director may invalidate a distribution total coliform-positive
sample if one of the following conditions is met.
(A) The executive director may invalidate a sample
if the laboratory provides written notice that improper sample analysis
caused the total coliform-positive result.
(B) The executive director may invalidate a sample
if the results of repeat samples collected, as required by this section,
determine that the total coliform-positive sample resulted from a
domestic or other non-distribution system plumbing problem. The executive
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. Under those circumstances,
the system may request that the executive director invalidate the
sample. The system must provide copies of the routine positive and
all repeat samples. The executive director may not invalidate a total
coliform-positive sample solely on the grounds that all repeat samples
are total coliform-negative or if the system has only one service
connection.
(C) The executive director may invalidate a sample
if there are substantial grounds to believe that the 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 system
must still collect all repeat samples required by this section, and
use them to determine compliance with the E.
coli MCL as described in subsection (g) of this section and
whether a coliform treatment technique trigger has been exceeded as
described in subsection (c) of this section. The system must provide
written documentation which must state the specific cause of the total
coliform-positive sample, and the action the system has taken, or
will take, to correct this problem. The system must obtain the written
and signed approval from the executive director before the sample
can be invalidated under this condition. The executive director may
not invalidate a total coliform-positive sample solely on the grounds
that all repeat samples are total coliform-negative.
(D) The executive director may invalidate a sample
if the laboratory provides written notice that the sample was unsuitable
for analysis and the laboratory invalidated the sample based on the
requirements of 40 CFR §141.853(c)(2). When the sample is invalidated
under this condition, the system must collect another sample from
the same location as the original sample within 24 hours of being
notified, and have it analyzed for the presence of total coliforms.
The system must continue to re-sample within 24 hours and have the
samples analyzed until it obtains a valid result. The executive director
may waive the 24-hour time limit on a case-by-case basis. Alternatively,
the executive director may implement criteria for waiving the 24-hour
sampling time limit to use in lieu of case-by-case extension.
(E) If a sample is invalidated by the laboratory, the
public water system must collect another sample from the same location
as the original sample within 24 hours of being notified, or as soon
as possible if the laboratory is closed, and have it analyzed for
the presence of total coliform. The system must continue to resample
within 24 hours and have the samples analyzed until it obtains a valid
result.
(2) A groundwater system may obtain invalidation of
a fecal indicator positive groundwater source sample if the conditions
of subparagraphs (A) and (B) of this paragraph apply. If the executive
director invalidates a fecal indicator positive groundwater source
sample, the system must collect another source sample as specified
in subsection (d)(4) of this section within 24 hours of being notified
of the invalidation.
(A) Notice from the laboratory must document that improper
sample analysis occurred. If a laboratory invalidates a sample, the
system must collect another sample from the same location as the original
sample within 24 hours of being notified of the invalidated sample,
and have it analyzed for the presence of E.
coli (or other approved fecal indicator). The public water
system must continue to re-sample within 24 hours and have the samples
analyzed until it obtains a valid result. If approved by the executive
director, the 24-hour time limit may be extended.
(B) The executive director may invalidate the sample
if the public water system provides written documentation that there
is substantial evidence that a fecal indicator positive groundwater
source sample is not related to source water quality. If the executive
director invalidates a sample, the public water system must collect
another sample from the same location as the original sample within
24 hours of being notified of the invalidated sample, and have it
analyzed for the presence of E. coli (or
other approved fecal indicator).
(3) Culture analysis. If any distribution system coliform
sample is total coliform-positive, that total coliform-positive medium
will be analyzed to determine if E. coli are
present. If E. coli are present, the
public water system shall notify the executive director by the end
of the day in accordance with subsection (h) of this section. If any
raw groundwater source sample is used to meet the repeat requirements
of subsection (d)(3)(C)(ii) and (4)(B)(iii) then it must be analyzed
to determine if E. coli are present.
(f) Reporting requirements for microbial contaminants.
The owner or operator of a public water system must ensure the executive
director is provided with a copy of the results of any test, measurement,
or analysis required by this subsection. The copies must be submitted
within the first ten days following the month in which the result
is received by the public water system, or the first ten days following
the end of the required monitoring period as provided by this subsection,
whichever occurs first. The copies must be mailed to the Water Supply
Division, MC 155, Texas Commission on Environmental Quality, P.O.
Box 13087, Austin, Texas 78711-3087.
(g) Compliance determination for microbial contaminants.
Compliance with the requirements of this section shall be determined
using the following criteria each month that the system is in operation.
(1) A public water system commits an E. coli MCL violation if any of the following
conditions occur:
(A) The public water system has an E. coli -positive repeat samples following
a total coliform-positive routine sample;
(B) The public water system has a total coliform-positive
repeat sample following an E. coli -positive
routine sample;
(C) The public water system fails to take all required
repeat samples following an E. coli -positive
routine sample; or
(D) The public water system fails to test for E. coli when any repeat sample tests positive
for total coliform.
(2) If all repeat samples taken for triggered source
water monitoring are E. coli -negative
and a repeat sample taken at a monitoring location other than the
one required for triggered source water monitoring is E. coli -positive, the public water system
has violated the E. coli MCL, but
is not required to comply with subsection (d)(4)(B)(iv) of this section.
If a public water system takes more than one repeat sample at the
monitoring location required for triggered source water monitoring
under subsection (d)(4) of this section, and more than one repeat
sample is E. coli -positive, the public
water system has violated the E. coli MCL
and shall also comply with the treatment technique and corrective
action requirements as described in §290.116 of this title.
(3) A public groundwater system that is required to
collect raw source samples is required to conduct corrective action
as described in §290.116 of this title and is required to provide
public notification in accordance with §290.122(a) of this title
if a source sample is confirmed positive for E.
coli or other approved fecal indicator.
(4) A public water system that fails to collect every
required routine sample in a compliance period and/or to submit the
analytical results to the executive director commits a monitoring
violation.
(5) A public water system that fails to analyze for E. coli following a total coliform-positive
routine sample commits a monitoring violation.
(6) A public water system that fails to monitor in
accordance with the requirements of subsection (d)(4) of this section
commits a monitoring violation and must provide public notification
in accordance with §290.122 of this title.
(7) A public water system that fails to report the
results of the monitoring tests required by this section commits a
reporting violation.
(8) A public water system that fails to do a required
public notice or certify that notification has been performed commits
a public notice reporting violation.
Cont'd... |
