| (a) Applicability. All public water systems must produce
and distribute water that meets the provisions of this section regarding
microbial contaminants.
(b) Maximum contaminant levels (MCL) for microbial
contaminants. Treatment techniques and MCL requirements for microbial
contaminants are based on detection of those contaminants or fecal
indicator organisms.
(1) A public water system is in compliance with the
MCL for Escherichia coli (E. coli) unless
any of the following conditions occur:
(A) The public water system has an E. coli -positive repeat sample 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.
(E) The E. coli MCL
is defined as when a condition described in subparagraphs (A) - (D)
of this paragraph occurs.
(2) For public water systems required to collect raw
groundwater samples, the standard is no detection of fecal indicators
in a raw groundwater sample.
(c) Treatment technique triggers and assessment requirements
for microbial contaminants. All public water systems shall comply
with the requirements as described in this subsection. Public water
systems shall conduct assessments after exceeding any of the treatment
technique triggers as described in paragraphs (1) and (2) of this
subsection.
(1) Level 1 treatment technique triggers are:
(A) For a public water system which collects 40 or
more distribution samples per month, the treatment technique trigger
is defined as when more than 5.0% of samples collected in a month
are total coliform-positive.
(B) For a public water system which collects fewer
than 40 distribution samples per month, the treatment technique trigger
is defined as when two or more samples collected in a month are total
coliform-positive.
(C) When a public water system fails to collect all
required repeat samples after a total coliform-positive result.
(2) Level 2 treatment technique triggers are:
(A) An E. coli MCL
violation as specified in subsection (b)(1)(A) - (D) of this section
occurs.
(B) A second Level 1 treatment technique trigger occurs
as defined in paragraph (1) of this subsection, within a rolling 12-month
period. If the executive director has determined the reason that the
samples that caused the first Level 1 treatment technique trigger
were total coliform-positive and has established that the public water
system has corrected the problem, a public water system will not be
required to conduct and complete a Level 2 assessment. The public
water system shall have identified any sanitary defect and provided
adequate documentation to the executive director in the initial Level
1 assessment which established the reason that caused the first Level
1 treatment technique trigger and that the public water system corrected
the problem. If the executive director has determined that a public
water system is not required to conduct a Level 2 assessment based
on the occurrence of a second Level 1 treatment technique trigger
within a rolling 12-month period, the public water system shall still
conduct the required Level 1 assessment and shall complete and submit
the executive director-approved Level 1 assessment form.
(3) Treatment technique assessment requirements are:
(A) Level 1 and Level 2 assessments are conducted in
order to identify the possible presence of sanitary defects and defects
in distribution system coliform monitoring practices. The assessments
may also indicate that no sanitary defects were identified. When conducting
assessments, systems shall ensure that the assessor evaluates minimum
elements that include review and identification of inadequacies in
sample sites; sampling protocol; sample processing; atypical events
that could affect distributed water quality or indicate that distributed
water quality was impaired; changes in distribution system maintenance
and operation that could affect distributed water quality (including,
but not limited to water storage); source and treatment considerations
that bear on distributed water quality; and existing water quality
monitoring data. The system shall conduct and complete the assessment
in the format as prescribed by the executive director that tailors
specific assessment elements with respect to the size and type of
the system and the size, type, and characteristics of the distribution
system.
(i) Level 1 and Level 2 assessments shall be conducted
and completed by the public water system, licensed operators as required
under §290.46(e) of this title (relating to Minimum Acceptable
Operating Practices for Public Drinking Water Systems), or other parties
approved by the executive director. The public water system, licensed
operators, as required under §290.46(e) of this title, and other
parties approved by the executive director shall have also completed
training as required in clause (iii) of this subparagraph and any
additional training required by the executive director in writing,
upon notice to the public water system, licensed operators, and other
parties approved by the executive director.
(ii) Other parties approved by the executive director
include, but are not limited to:
(I) backflow prevention assembly testers and customer
service inspectors licensed under Chapter 30 of this title (relating
to Occupational Licenses and Registrations);
(II) plumbing inspectors and water supply protection
specialists licensed by the Texas State Board of Plumbing Examiners;
(III) licensed professional engineers licensed by the
Texas Board of Professional Engineers;
(IV) circuit riders or technical assistance providers
under contract with the executive director or other government agency
as approved by the executive director; or
(V) utility supervisor or manager supported by various
utility staff or other individuals that meet the assessment requirements
as described in this paragraph.
(iii) Assessors who have conducted Level 1 assessments
which were determined by the executive director to be insufficient
or inadequate may be required to complete additional training or obtain
certifications as prescribed by the executive director.
(B) The Level 1 and Level 2 assessments shall be conducted
and completed consistent with all directives set forth by the executive
director and with respect to the size, type, and characteristics of
the public water system. When conducting assessments, at a minimum,
public water systems shall ensure that the following items are evaluated:
(i) review and identification of inadequacies in sample
sites;
(ii) sampling protocol;
(iii) sample processing;
(iv) atypical events that could affect distributed
water quality or indicate that distributed water quality was impaired;
(v) changes in distribution system maintenance and
operation that could affect distributed water quality (including,
but not limited to water storage);
(vi) source and treatment considerations that bear
on distributed water quality, where appropriate;
(vii) existing water quality monitoring data; and
(viii) the possible presence of sanitary defects.
(C) A public water system shall conduct a Level 1 assessment
and complete the executive director-approved Level 1 assessment form
when the public water system exceeds one of the treatment technique
triggers in paragraph (1) of this subsection. The public water system
must note no sanitary defects were identified or describe sanitary
defects detected, corrective actions completed, and a proposed timetable
for any corrective actions not already completed in the Level 1 assessment
form. At the discretion of the executive director, the public water
system shall comply with any additional or expedited corrective actions
when there is a potential for an acute health risk.
(i) Both the Level 1 assessment and the executive director-approved
Level 1 assessment form shall be completed and the form submitted
to the executive director as soon as practical, but no later than
30 days after the public water system learns that it has exceeded
a trigger, or 30 days after all routine and repeat monitoring was
required to be completed for the calendar month in which the system
exceeded the trigger, whichever is earlier.
(ii) If the executive director determines that the
Level 1 assessment is not sufficient, the public water system shall
consult with the executive director and submit a revised assessment
form to the executive director within 30 days from the date of consultation.
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