SECTION 290.109. Microbial Contaminants

(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.

(iii) The executive director will determine if the public water system has identified the likely cause(s) of the trigger and, if so, was the cause(s) corrected, or has an acceptable schedule to correct the problem been included. The assessments may also indicate that no sanitary defects were identified.

(D) A public water system shall ensure that a Level 2 assessment and the executive director-approved Level 2 assessment form are conducted and completed consistently with all directives set forth by the executive director if the public water system exceeds one of the treatment technique triggers in paragraph (2) of this subsection. The public water system shall comply with any expedited actions or additional actions required by the executive director in the case of an E. coli MCL violation.

(i) After any trigger in paragraph (2) of this subsection, the public water system shall ensure that both the Level 2 assessment and the executive director-approved Level 2 assessment form are completed by the public water system, licensed operators as required under §290.46(e) of this title, or by parties approved by the executive director and the completed 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 in paragraph (2) of this subsection, 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 completed Level 2 assessment is not sufficient or the proposed timetable for any corrective actions not completed is not sufficient, the public water system shall consult with the executive director. If any revisions are required after consultation, the public water system shall submit a revised assessment form to the executive director within 30 days from the date of the consultation.

(iii) After the Level 2 assessment is submitted, the executive director will determine if the public water system has identified the likely cause(s) of the trigger and corrected the cause(s), or has included an acceptable timetable for correcting the cause(s). The assessments may also indicate that no sanitary defects were identified.

(E) Public water systems must correct sanitary defects found through either Level 1 or Level 2 assessments described in this subsection. For corrective actions not completed by the time of submission of the assessment form, the public water system must complete the corrective actions in compliance with a timetable approved by the executive director in consultation with the public water system. The public water system must notify the executive director when scheduled corrective actions have been completed.

(F) At any time during the assessment or corrective action phase, either the public water system or the executive director may request a consultation with the other party to determine the appropriate actions. The public water system shall consult with the executive director on all relevant information that may impact its ability to comply with a requirement of this subsection.

(d) Monitoring requirements for microbial contaminants. Public water systems shall collect samples for total coliform, fecal coliform, E. coli (or other approved fecal indicator) at sampling sites and a sample collection schedule, as designated by the public water system, which are subject to review and revision as directed by the executive director. All compliance samples must be collected at sampling sites and a sample collection schedule that are representative of water throughout the distribution system and shall be reflected in the public water system's Sample Siting Plan and included with the public water system's monitoring plan in accordance with §290.121 of this title (relating to Monitoring Plans). All public water systems shall develop a written Sample Siting Plan as described in paragraph (6) of this subsection.

(1) Routine microbial sampling locations. Public water systems shall routinely monitor for microbial contaminants at the following locations.

(A) Public water systems must collect routine distribution coliform samples at a customer's premise, dedicated sampling station, or other designated compliance sampling location at active service connections which are representative of water quality throughout the distribution system. Other sampling sites may be used if located adjacent to active service connections.

(B) Public water systems shall collect distribution coliform samples at locations specified in the public water system's Sample Siting Plan which shall be included in the public water system's monitoring plan.

(2) Routine distribution coliform sampling frequency. All public water systems must sample for distribution coliform at the following frequency.

(A) Community and noncommunity public water systems must collect routine distribution coliform samples at a frequency based on the population served by the system.

(i) The population for noncommunity systems will be based on the maximum number of persons served on any given day during the month based on the data reported by the public water system to the executive director during the most recent sanitary survey of the public water system or any other data as required by the executive director.

(ii) The population of community systems will be based on the data reported by the public water system to the executive director during the most recent sanitary survey of the public water system or any other data as required by the executive director.

(iii) The minimum sampling frequency for public water systems is shown in the following table.

Attached Graphic

(B) A public water system which uses surface water or groundwater under the direct influence of surface water must collect routine distribution coliform samples at regular time intervals throughout the month.

(C) A public water system which uses only purchased water or groundwater not under the direct influence of surface water and serves more than 4,900 persons must collect routine distribution coliform samples at regular time intervals throughout the month.

(D) A public water system which uses only purchased water or groundwater not under the direct influence of surface water and serves 4,900 persons or fewer may collect all required routine distribution coliform samples on a single day if they are taken from different sites.

(E) A total coliform-positive sample invalidated under this subsection does not count towards meeting the minimum routine monitoring requirements of this subsection. Unless the executive director has invalidated the sample in accordance with subsection (e) of this section, all routine coliform sample results must be used to determine compliance with subsection (b)(1) of this section and to determine treatment technique trigger and assessment requirements as described in subsection (c)(1) and (2) of this section.

(F) All public water system shall collect at least the minimum number of required routine microbial samples even if the public water system has had an E. coli MCL violation under any of the conditions as described in subsection (b)(1)(A) - (D) of this section or has exceeded the coliform treatment technique triggers as described in subsection (c)(1) and (2) of this section.

(G) A public water system may conduct more microbial compliance monitoring than is required by this subsection to investigate potential problems in the public water system treatment facilities and distribution system and use monitoring to assist in identifying problems. A public water system may collect more than the minimum number of required routine samples required by this subsection. A public water system that collects more than the minimum number of required routine samples required by this subsection shall include the results of these samples in calculating whether the coliform treatment technique triggers as described in subsection (c)(1) and (2) of this section have been exceeded. The additional routine sample sites shall be included in the public water system's Sample Siting Plan and collected in accordance with the Sample Siting Plan and shall be representative of water throughout the distribution system.

(3) Repeat distribution coliform sampling requirements. Public water systems shall conduct repeat monitoring if one or more of the routine samples is found to contain coliform organisms.

(A) If a routine distribution coliform sample is coliform-positive, the public water system must collect a set of repeat distribution coliform samples within 24 hours of being notified of the positive result, or as soon as possible if the local laboratory is closed. The executive director may extend the 24-hour limit on a case-by-case basis if the public water system has a logistical problem in collecting the repeat samples within 24 hours that is beyond the public water system's control. All public water systems shall collect no fewer than three repeat samples for each total coliform-positive sample found even if the public water system has had an E. coli MCL violation under any of the conditions as described in subsection (b)(1)(A) - (D) of this section or has exceeded the coliform treatment technique triggers as described in subsection (c)(1) and (2) of this section.

(B) The public water system must collect all repeat samples on the same day, except a public water system with a single service connection may collect daily repeat samples over a three-day period until the required number of repeat samples has been collected.

(C) Unless the public water system meets the provisions of clause (i) or (ii) of this subparagraph, the public water system must collect at least one repeat sample from the sampling tap where the original 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 the positive routine sample was collected at the end of the distribution system, or one service connection away from the end of the distribution system, one repeat sample must be collected at that point and the other two repeat samples must be collected within five connections upstream of that point.

(i) As approved by the executive director, public water systems may propose repeat monitoring locations to the executive director that the public water system considers to be representative of a pathway for contamination of the distribution system. A public water system may elect to specify either alternative fixed locations or criteria for selecting repeat sampling sites on a situational basis in a written standard operating procedure (SOP) in its Sample Siting Plan. The public water system shall design its SOP to focus the repeat samples at locations that best verify and determine the extent of potential contamination of the distribution system area based on specific situations. The executive director may modify the SOP or require alternative monitoring locations as needed.

(ii) As approved by the executive director, groundwater public water systems serving 1,000 or fewer people may propose repeat sampling locations to the executive director, in a written SOP in its Sample Siting Plan, that differentiate potential source water and distribution system contamination (e.g., by sampling at entry points to the distribution system). A groundwater public water system with a single well required to conduct triggered source water monitoring may, with written executive director approval, take one of its repeat samples at the monitoring location required for triggered source water monitoring under paragraph (4) and (4)(A) of this subsection if the public water system demonstrates to the executive director that the Sample Siting Plan remains representative of water quality in the distribution system. If approved by the executive director, the public water system may use that sample result to meet the monitoring requirements for both repeat monitoring under this paragraph and triggered source monitoring under paragraph (4) and (4)(A) of this subsection.

(iii) All public water systems shall include all sample sites as required by this subparagraph and any required SOPs for any proposed sampling sites as described in clauses (i) and (ii) of this subparagraph in the public water system's Sample Siting Plan in accordance with paragraph (6) of this subsection.

(D) If one or more repeat samples in the set is total coliform-positive, the public water system must collect an additional set of repeat samples in the manner specified in subparagraphs (A) - (C) of this paragraph. The additional samples must be collected within 24 hours of the public water system being notified of the positive result or as soon as possible if the local laboratory is closed. The executive director may extend the 24-hour limit on a case-by-case basis if the public water system has a logistical problem in collecting the repeat samples within 24 hours that is beyond the public water system's control. In accordance with 40 Code of Federal Regulations (CFR) §141.858(a)(1) the executive director is prohibited from waiving the requirement for a public water system to collect repeat samples as specified in subparagraphs (A) - (D) of this paragraph. The public water system must repeat this process until either one of the following occurs:

(i) total coliforms are not detected in one complete set of repeat samples;

(ii) a coliform treatment technique trigger as described in subsection (c)(1) and (2) of this section has been exceeded; or

(iii) If a treatment technique trigger as described in subsection (c)(1) and (2) of this section is exceeded as a result of a routine sample being total coliform-positive, public water systems are required to conduct only one round of repeat monitoring for each total coliform-positive routine sample.

(E) After a public water system collects a routine sample and before it learns the results of the analysis of that sample, if it collects another routine sample(s) from within five adjacent service connections of the initial sample, and the initial sample is found to contain total coliform bacteria, then the public water system may count the subsequent sample(s) as a repeat sample instead of as a routine sample.

(F) A total coliform-positive sample invalidated under this subsection does not count towards meeting the minimum repeat monitoring requirements of this subsection. Unless the executive director has invalidated the sample in accordance with subsection (e) of this section, all repeat coliform sample results must be used to determine compliance with subsection (b)(1) of this section and to determine treatment technique trigger and assessment requirements as described in subsection (c)(1) and (2) of this section.

(4) General requirements for raw groundwater source monitoring. Groundwater systems must comply, unless otherwise noted, with the requirements of this section. Any raw groundwater source sample required under this paragraph must be collected at a location prior to any treatment of the groundwater source and use analytical procedures and methods described in §290.119(b)(10) of this title (relating to Analytical Procedures). The public water system may collect a sample at an executive director-approved location prior to any treatment to meet the requirements of this paragraph and subparagraph (A) of this paragraph if the sample is representative of the water quality of that well.

(A) Triggered source monitoring general requirements. A groundwater system must conduct triggered source water monitoring for E. coli (or other approved fecal indicator), if both of the following conditions exist.

(i) The system does not provide at least 4-log treatment of viruses (as defined in §290.103(44) of this title (relating to Definitions)) before the first customer for each groundwater source; and

(ii) The system is notified that a routine distribution coliform sample is positive and the sample is not invalidated under subsection (e)(1) of this section.

(B) Triggered source monitoring sampling requirements. A groundwater system must collect, within 24 hours of notification of the routine distribution total coliform-positive sample, at least one raw groundwater source E. coli (or other approved fecal indicator) sample from each groundwater source in use at the time the distribution coliform-positive sample was collected.

(i) The executive director may extend the 24-hour time limit on a case-by-case basis if the system cannot collect the raw groundwater source sample within 24 hours due to circumstances beyond its control. If the executive director extends the 24-hour time limit on a case-by-case basis, the public water system must collect the sample within 48 hours.

(ii) If approved by the executive director and documented in the public water system's monitoring plan, public water systems with more than one groundwater source may be allowed to sample a representative groundwater source or sources. Public water systems shall modify their current monitoring plan to identify one or more groundwater sources that are representative of each distribution coliform sampling site and is intended to be used for representative source sampling.

(iii) A groundwater system with one well serving 1,000 people or fewer may use one of the three required repeat samples collected from a raw groundwater source to meet both the repeat requirements of paragraph (3) of this subsection and the triggered raw source monitoring requirements in this paragraph when all of the following requirements are met:

(I) the fecal indicator used is E. coli;

(II) the executive director has provided written approval for the public water system to meet the monitoring requirements for both repeat monitoring under paragraph (3) of this subsection and triggered source monitoring under this paragraph and subparagraph (A) of this paragraph; and

(III) the public water system's sample siting plan remains representative of water quality in the distribution system. If a required repeat sample is used to meet both requirements and found to be E. coli -positive, the public water system will have achieved an E. coli MCL as defined in subsection (b)(1)(A) - (D) of this section and corrective action will be required for the groundwater source where the sample was found to be E. coli -positive.

(iv) If the executive director does not require corrective action under §290.116 of this title (relating to Groundwater Corrective Actions and Treatment Techniques) for a fecal indicator positive source water sample collected under this subparagraph that is not invalidated under subsection (e) of this section, the public water system shall collect five additional source water samples from the same source within 24 hours of being notified of the fecal indicator positive sample.

(v) If a public water system takes more than one repeat sample at the monitoring location required for triggered source water monitoring, the public water system may reduce the number of additional source water samples required under clause (iv) of this subparagraph by the number of repeat samples taken at that location that were not E. coli- positive.

(C) Consecutive and wholesale systems. Consecutive groundwater systems receiving drinking water from a wholesaler must notify the wholesale system(s) within 24 hours of being notified of the positive coliform distribution sample. The wholesale groundwater system(s) must comply with the following:

(i) A wholesale groundwater system that receives notice of a distribution coliform sample positive from a consecutive system it serves must collect a sample from each of its groundwater sources within 24 hours of the notification and analyze each sample for the presence of E. coli (or other approved fecal indicator).

(ii) If any raw source sample is E. coli (or other approved fecal indicator) positive, the wholesale groundwater system must notify all consecutive systems served by that groundwater source of the fecal indicator positive within 24 hours of being notified. The wholesale system and all consecutive systems served by that groundwater source must notify their water system customers in accordance with subsection (h)(2) of this section and shall meet the requirements of subparagraph (B)(iv) of this paragraph.

(iii) If any raw source sample is E. coli positive, the wholesale groundwater system shall notify all consecutive systems served by that groundwater source of the fecal indicator source water positive within 24 hours of being notified and shall meet the requirements of subparagraph (B)(iv) of this paragraph.

(D) Exceptions to the triggered source monitoring requirements. A groundwater system is not required to comply with the triggered source monitoring requirements if any of the following conditions exist.

(i) The executive director determines and documents in writing, that the distribution coliform-positive sample is caused by a distribution system deficiency; or

(ii) The distribution coliform-positive sample is collected at a location that meets the distribution coliform sample invalidation criteria as specified in subsection (e)(1) of this section and the replacement sample is negative for coliforms.

(E) Assessment source monitoring. The executive director may require monthly source assessment raw monitoring without the presence of a positive total coliform distribution sample if well conditions exist that indicate the groundwater may be susceptible to fecal contamination. The executive director may conduct a hydrogeological sensitivity assessment to determine if the source is susceptible to fecal contamination. If requested by the executive director, groundwater systems must provide the executive director with any existing information that will enable the executive director to perform a hydrogeological sensitivity assessment. A groundwater system conducting assessment source monitoring may use a triggered source sample collected under subparagraph (A) of this paragraph to meet the assessment source monitoring requirement. A groundwater system with a groundwater source sample collected under this subparagraph or under subparagraph (A) of this paragraph that is fecal indicator positive and that is not invalidated under subsection (e)(2) of this section, including consecutive systems served by the groundwater source, shall conduct public notification under §290.122(a) of this title (relating to Public Notification). Additionally, an assessment source monitoring sample may be used as a triggered source monitoring sample if collected within 24 hours of notification of the coliform-positive distribution sample. Assessment source monitoring requirements may include:

(i) Source monitoring, collected in a manner described in §290.119(b)(10) of this title, for a period of 12 months that represents each month that the system provides groundwater to the public from the raw groundwater source or such time period as specified by the executive director.

(ii) Collection of samples from each well unless the system has an approved triggered source monitoring plan under subparagraph (B)(ii) of this paragraph.

(5) Culture analysis. If any routine or repeat 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.

(6) Sample Siting Plan requirements. All public water systems shall develop and complete a written Sample Siting Plan as described in this paragraph that identifies routine and repeat microbial sampling sites and a sample collection schedule as required by this subsection that are representative of water throughout the distribution system. The Sample Siting Plan shall include all groundwater sources and any associated sampling points necessary to meet the requirements of this subsection. The Sample Siting Plan shall be included as a part of the public water system's monitoring plan as described in §290.121 of this title. Sample Siting Plans shall be completed in a format specified by the executive director and are subject to review and revision by the executive director.

(A) All public water systems shall collect routine and repeat samples according to a written Sample Siting Plan. All routine and repeat sample site locations, any required SOP, and any sampling point locations necessary to meet the requirements of this subsection shall be reflected in the written Sample Siting Plan. For community and noncommunity public water systems serving 1,000 or fewer people using only groundwater, the executive director shall evaluate during every sanitary survey (on-site inspection) the water system factors (including but not limited to pertinent water quality, compliance history, distribution system, all the components of a sanitary survey and its findings) to ensure the timeframe during the month, locations, and number of microbial compliance monitoring sample sites are adequate for producing and distributing safe drinking water.

(B) All public water systems shall include any required SOP for any proposed repeat sampling sites as described in paragraph (3)(C) of this subsection in the Sample Siting Plan. As required by the executive director, the executive director may review, revise, and approve any repeat sampling proposed by public water systems under paragraph (3)(C) of this subsection.

(C) The Sample Siting Plan shall include a distribution system map or series of maps which identifies distribution system valves and mains as described in §290.46(n)(2) of this title. The distribution system map shall also include the location of all routine microbial sample sites, water main sizes, entry point source locations, water storage facilities, and any pressure plane boundaries.

(D) All public water systems shall update their written Sample Siting Plan and map as necessary, or as requested by the executive director, to identify the most current microbial routine and repeat sampling sites and a sample collection schedule that are representative of water throughout the public water system's distribution system.

(E) All public water systems shall maintain a copy of their updated Sample Siting Plan and map on-site at the public water system for inspection purposes and at the request of the executive director, provide a copy of their Sample Siting Plan and/or map to the executive director for review and/or revision purposes.

(e) Analytical and invalidation requirements for microbial contaminants. Analytical procedures shall be performed in accordance with §290.119 of this title. Testing for microbial contaminants shall be performed at a laboratory certified by the executive director. The public water system must use a certified laboratory certified for each method and associated contaminant(s) for compliance analyses in accordance with §290.119 of this title.

(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.

(9) The results of all routine and repeat distribution coliform samples or groundwater source samples not invalidated by the executive director shall be included in determining compliance with the E. coli MCL as described in paragraph (1)(A) - (D) of this subsection and whether a coliform treatment technique trigger has been exceeded as described in subsection (c) of this section.

(10) The results of all routine and repeat distribution coliform samples or groundwater source samples invalidated by the executive director shall not be included in determining compliance with the E. coli MCL as described in paragraph (1)(A) - (D) of this subsection and whether a coliform treatment technique trigger has been exceeded as described in subsection (c) of this section.

(11) Special purpose samples, such as those taken to determine whether disinfection practices are sufficient following pipe placement, replacement, or repair, shall not be used to determine compliance with the MCL for microbiological contaminants. Special purpose samples shall not be used to determine whether the coliform treatment technique trigger has been exceeded as described in subsection (c) of this section. Coliform samples taken in accordance with subsection (d)(3) of this section and that are not invalidated under subsection (e) of this section are not considered special purpose samples.

(12) All seasonal public water systems shall complete executive director-approved start-up procedures and certification and maintain a copy of the start-up procedures and certification on-site at the public water system for inspection purposes. A seasonal system must certify, prior to serving water to the public, that it has complied with the executive director-approved start-up procedures. At the executive director's request, seasonal public water systems shall submit a copy of the start-up procedures and certification to the executive director for review purposes. Failure by a seasonal public water system to complete executive director-approved start-up procedures prior to serving water to the public is a treatment technique violation. Failure by a seasonal public water system to maintain or submit certification of completion of executive director-approved start-up procedures is a reporting violation.

(13) A public water system commits a treatment technique violation when a seasonal public water system fails to complete an executive director-approved start-up procedure prior to serving water to the public.

(14) A public water system commits a treatment technique violation when a public water system exceeds a treatment technique trigger specified in subsection (c) of this section and then fails to conduct the required assessment or corrective actions within the timeframe specified in subsection (c) of this section.

(15) A public water system required to conduct an assessment under the provisions of subsection (c) of this section shall submit the assessment report to the executive director within 30 days. The public water system shall notify the executive director in accordance with subsection (c) of this section when scheduled corrective actions are complete and for corrective actions not completed by the time of submission of the assessment form. For corrective actions not completed by the time of submission of the assessment form to the executive director, the public water system shall complete corrective actions in compliance with a timetable approved by the executive director in consultation with the public water system. The assessment may also indicate that no sanitary defects were identified.

(16) A public water system that fails to notify the executive director before the end of the day in accordance with subsection (h)(3) of this section commits a reporting violation.

(h) Public notification for microbial contaminants. A public water system that is out of compliance with the requirements described in this section must notify the public using the procedures described in §290.122 of this title for microbial contamination.

(1) A public water system that commits an acute MCL violation for microbial contaminants must notify the public water system customers in accordance with the boil water notice requirements of §290.46(q) of this title and the public notice requirements of §290.122(a) of this title.

(2) A public groundwater system that receives an E. coli (or other approved fecal indicator) positive source sample that has not been invalidated by the executive director, or a notice of an E. coli (or other approved fecal indicator) positive source sample from a wholesale system, including consecutive systems, must notify the public water system customers within 24-hours in accordance with the requirements of §290.122(a) of this title and include notice in the next Consumer Confidence Report for community public water systems or provide as a special notice for noncommunity systems in accordance with §290.272(g)(7) of this title (relating to Content of the Report) for community public water systems and §290.116(f)(2) of this title for noncommunity public water systems. Consecutive systems must issue public notice in accordance with §290.122(g) of this title. The public water system must continue to notify the public annually until the fecal contamination in the source water is determined by the executive director to be corrected as specified under §290.116 of this title.

(3) A public water system that has E. coli (or other approved fecal indicator) present must notify the executive director by the end of the day when the public water system is notified of the test result.

(4) A public water system which commits an MCL violation must report the violation to the executive director immediately after it learns of the violation, but no later than the end of the next business day, and notify the public in accordance with §290.122(b) of this title.

(5) A public water system which commits an E. coli MCL violation shall report the violation to the executive director immediately after it learns of the violation, but no later than the end of the day, and notify the public in accordance with §290.122(a) of this title.

(6) A public water system which has failed to comply with a coliform monitoring requirement must report the monitoring violation to the executive director within ten days after the system discovers the violation and notify the public in accordance with §290.122(c) of this title.

(7) A public water system that has committed a treatment technique trigger and assessment requirement for coliforms in subsection (c)(1) and (2) of this section and commits a treatment technique violation as described in subsection (g)(15) of this section shall report the violation to the executive director no later than the end of the next business day after it learns of the violation, and notify the public in accordance with §290.122(b) of this title.

(8) A public water system that commits a treatment technique violation for failure to complete and certify seasonal system start-up procedures as described in subsection (g)(10) and (11) of this section shall report the violation to the executive director no later than the end of the next business day after it learns of the violation, and notify the public in accordance with §290.122(b) of this title. In the notification in accordance with §290.122(b) of this title, if a seasonal system fails to monitor for total coliforms or E. coli prior to serving water to the public, it must include the following language: We are required to monitor your drinking water for specific contaminants on a regular basis. Results of regular monitoring are an indicator of whether or not your drinking water meets health standards. During {COMPLIANCE PERIOD}, we "did not monitor or test" or "did not complete all monitoring or testing" for {CONTAMINANT(S)}, and therefore cannot be sure of the quality of your drinking water during that time.

(i) The executive director, pursuant to 40 CFR §141.63(e), recognizes the following as the best technology, treatment techniques, or other means available for achieving compliance with the MCL for E. coli as described in subsection (b)(1)(A) - (D) of this section as follows:

(1) protection of wells from fecal contamination by appropriate placement and construction;

(2) maintenance of a disinfectant residual throughout the distribution system;

(3) proper maintenance of the distribution system including appropriate pipe replacement and repair procedures, main flushing programs, proper operation and maintenance of storage tanks and reservoirs, cross-connection control, and continual maintenance of positive water pressure in all parts of the distribution system;

(4) filtration and disinfection of surface water, as described in this chapter, or disinfection of groundwater, as described in chapter, using strong oxidants such as chlorine, chlorine dioxide, or ozone;

(5) for systems using groundwater, development and implementation of a Wellhead Protection Program, as directed by the executive director, and in accordance with the federal Safe Drinking Water Act, United States Code, §1428; or

(6) the executive director may require additional best technology, treatment techniques, or other means available for achieving compliance with the MCL for E. coli as described in subsection (g)(1) of this section.

Source Note: The provisions of this §290.109 adopted to be effective September 13, 2000, 25 TexReg 8880; amended to be effective May 16, 2002, 27 TexReg 4127; amended to be effective January 9, 2008, 33 TexReg 198; amended to be effective November 8, 2012, 37 TexReg 8849; amended to be effective September 12, 2013, 38 TexReg 5880; amended to be effective March 30, 2017, 42 TexReg 1466