1. (a) Applicability. All public water systems must produce and distribute water that meets the provisions of this section regarding microbial contaminants.

2. (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. (1) The MCL for microbial contaminants in the distribution system is based on the presence of total or fecal coliform bacteria in routine, repeat, and increased monitoring distribution samples.

      1. (A) For a system which collects at least 40 routine distribution samples per month, the MCL is defined as when more than 5.0% of samples collected in a month are coliform positive.
      2. (B) For a system which collects fewer than 40 routine distribution samples per month, the MCL is defined as when more than one sample is coliform positive.
      3. (C) The acute MCL is defined as when a repeat sample is fecal coliform or Escherichia coli (E. coli) positive; or a total coliform positive repeat sample follows a fecal coliform or E. coli positive routine sample.
   2. (2) For systems required to collect raw groundwater samples, the standard is no detection of fecal indicators in a raw groundwater samples.

3. (c) Monitoring requirements for microbial contaminants. Public water systems shall collect samples for total coliform, fecal coliform, E. coli, or other fecal indicator organisms at locations and frequency as directed by the executive director. All compliance samples must be collected during normal operating conditions.

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

      1. (A) Public water systems must collect routine distribution coliform samples 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.
      2. (B) Public water systems shall collect distribution coliform samples at locations specified in the system's monitoring plan.

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

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

         1. (i) the population for noncommunity systems will be based on the maximum number of persons served on any given day during the month;
         2. (ii) the population of community systems will be based on the data reported during the most recent sanitary survey of the public water system; and
         3. (iii) the minimum sampling frequency for public water systems is shown in the following table.
            Attached Graphic
            
      2. (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.
      3. (C) A public water system which uses only 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.
      4. (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.
      5. (E) A total coliform-positive sample invalidated under this subsection does not count towards meeting the minimum routine monitoring requirements of this subsection.
      6. (F) If a system collecting fewer than five routine distribution coliform samples per month has one or more total coliform-positive samples and the executive director does not invalidate the sample(s) in accordance with subsection (d)(1) of this section, it must collect at least five routine distribution coliform samples during the next month the system provides water to the public.

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

      1. (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.

         1. (i) A system which collects more than one routine distribution coliform sample per month must collect no fewer than three repeat samples for each coliform-positive sample found.
         2. (ii) A system which collects one routine distribution coliform sample per month must collect no fewer than four repeat samples for each coliform-positive sample found.
      2. (B) The system must collect all repeat samples on the same day, except a system with a single service connection may collect daily repeat samples until the required number of repeat samples has been collected.
      3. (C) The 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 a fourth repeat sample is required, it must be collected within five service connections upstream or downstream. If the positive routine sample was collected at the end of the distribution line, one repeat sample must be collected at that point and all other samples must be collected within five connections upstream of that point.
      4. (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 being notified of the positive result or as soon as possible if the local laboratory is closed. The system must repeat this process until either total coliforms are not detected in one complete set of repeat samples or the system determines that the MCL for total coliforms has been exceeded.
      5. (E) After a 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 system may count the subsequent sample(s) as a repeat sample instead of as a routine sample.

   4. (4) 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).

      1. (A) General requirements. A groundwater system must conduct triggered source water monitoring for E. coli or other fecal indicators, if both of the following conditions exist.

         1. (i) The system does not provide at least 4-log treatment of viruses (as defined in §290.103(39) of this title (relating to Definitions)) before the first customer for each groundwater source; and
         2. (ii) The system is notified that a routine distribution coliform sample is positive and the sample is not invalidated under subsection (d)(1) of this section.

      2. (B) 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.

         1. (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.
         2. (ii) If approved by the executive director and documented in the system's monitoring plan, systems with more than one groundwater source may be allowed to sample a representative groundwater source or sources. Systems must 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.
         3. (iii) A groundwater system serving 1,000 people or fewer may use one of the four required repeat samples collected from a raw groundwater source to meet both the repeat requirements of subparagraph (A)(ii) of this paragraph and the triggered raw source monitoring requirements in this paragraph. If a required repeat sample is used to meet both requirements and found to be E. coli positive, the system will have achieved an acute MCL as defined in subsection (b)(1)(C) of this section and corrective action will be required for the groundwater source were the sample was found to be E. coli positive.

      3. (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:

         1. (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.
         2. (ii) If any raw source sample is E. coli 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 (g)(2) of this section.

      4. (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.

         1. (i) The executive director determines and documents in writing, that the distribution coliform positive sample is caused by a distribution system deficiency; or
         2. (ii) The distribution coliform positive sample is collected at a location that meets the distribution coliform sample invalidation criteria as specified in subsection (d)(1) of this section and the replacement sample is negative for coliforms.

      5. (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 (B) of this paragraph to meet the assessment source monitoring requirement. 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:

         1. (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.
         2. (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. (5) Culture analysis. If any routine or repeat sample is total coliform-positive, that total coliform-positive culture medium will be analyzed to determine if fecal coliforms or bacteria are present. If fecal coliforms or E. coli are present, the system must notify the executive director by the end of the day in accordance with subsection (g) of this section.

4. (d) 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.

   1. (1) Distribution coliform sample invalidation. The executive director may invalidate a distribution total coliform-positive sample if one of the following conditions is met.

      1. (A) The executive director may invalidate a sample if the laboratory provides written notice that improper sample analysis caused the total coliform-positive result.
      2. (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 cease resampling and request that the executive director invalidate the sample. The system must provide copies of the routine positive and all repeat samples.
      3. (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 MCL for total coliforms in subsection (f) 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 executive director may not invalidate a total coliform-positive sample solely on the grounds that all repeat samples are total coliform-negative.
      4. (D) The executive director may invalidate a sample if the laboratory provides written notice that the sample was unsuitable for analysis.
      5. (E) If a sample is invalidated by the laboratory, the 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. (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 (c)(4) of this section within 24 hours of being notified of the invalidation.

      1. (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. The 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.
      2. (B) The executive director may invalidate the sample if the 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 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.
5. (e) Reporting requirements for microbial contaminants. Upon the request of the executive director, the owner or operator of a public water system must provide the executive director with a copy of the results of any test, measurement, or analysis required by this subsection. The copies must be submitted within ten days of the request or within ten days of their receipt by the public water system, whichever is later. 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.

6. (f) 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. (1) A system commits an acute MCL violation if:

      1. (A) A repeat distribution system sample is fecal coliform-positive or E. coli-positive; or
      2. (B) A total coliform-positive repeat distribution system sample follows a fecal coliform-positive or E. coli-positive routine distribution system sample.
   2. (2) A system that collects at least 40 routine distribution coliform samples per month commits a nonacute MCL violation if more than 5.0% of the samples collected during a month are total coliform-positive, but none of the initial or repeat samples are fecal coliform-positive or E. coli-positive.
   3. (3) A system that collects fewer than 40 routine distribution coliform samples per month commits a nonacute MCL violation if more than one sample collected during a month is total coliform-positive, but none of the initial or repeat samples are fecal coliform-positive or E. coli-positive.
   4. (4) 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 (relating to Groundwater Corrective Actions and Treatment Techniques) and is required to provide public notification in accordance with §290.122(a) of this title (relating to Public Notification) if a source sample is confirmed positive for E. coli or other approved fecal indicators.
   5. (5) A public water system that fails to provide the required number of suitable distribution coliform samples commits a monitoring violation.
   6. (6) A public water system that fails to monitor in accordance with the requirements of subsection (c)(4) of this section commits a monitoring violation and must provide public notification in accordance to §290.122 of this title.
   7. (7) A public water system that fails to report the results of the monitoring tests required by this section commits a reporting violation.
   8. (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. (9) Results of all routine and repeat distribution coliform samples not invalidated by the executive director must be included in determining compliance with the MCL for total coliforms.
   10. (10) Distribution coliform samples invalidated by the executive director shall not be included in determining compliance with the MCL for total coliforms.
   11. (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.

7. (g) Public notification for microbial contaminants. A 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. (1) A public water system that commits an acute MCL violation for microbial contaminants must notify the water system customers in accordance with the boil water notice requirements of §290.46(q) of this title (relating to Minimum Acceptable Operating Practices for Public Drinking Water Systems) and the public notice requirements of §290.122(a) of this title.
   2. (2) A public groundwater system that receives an E. colior other fecal indicator positive source sample that has not been invalidated by the executive director, or a notice of an E. coli or other fecal indicator positive source sample from a wholesale system, including consecutive systems, must notify the 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 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 water systems and §290.116(f)(2) of this title for noncommunity systems. Consecutive systems must issue public notice in accordance with §290.122(g) of this title. The 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. (3) A public water system that has fecal coliforms or E. coli present must notify the executive director by the end of the day when the system is notified of the test result, unless the system is notified of the result after the commission's office is closed, in which case the system must notify the executive director before the end of the next business day.
   4. (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. (5) 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.

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.