(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.
Cont'd...