1. (a) Applicability. All groundwater public water systems must comply with the treatment techniques and corrective actions of this section if a raw groundwater source sample was positive for fecal indicators or if the system is not required to conduct raw groundwater source monitoring because it provides at least 4-log treatment of viruses.

   1. (1) A groundwater system must provide written notification to the executive director before December 1, 2009, that it is not required to meet the raw groundwater source monitoring requirements under §290.109(c)(4) of this title (relating to Microbial Contaminants) because it provides at least 4-log treatment of viruses and begin compliance monitoring in accordance with subsection (c) this section. The notification must include engineering, operational, and other information required by the executive director to evaluate the submission. If the system discontinues 4-log treatment of viruses before the first customer for any groundwater source, the system must conduct raw groundwater source sampling as required under §290.109(c)(4) of this title.
   2. (2) A groundwater system that places a groundwater source in service after November 30, 2009, that is not required to meet the raw source monitoring requirements under §290.109(c)(4) of this title because the system provides at least 4-log treatment of viruses must begin compliance monitoring within 30 days of placing the source in service in accordance with subsection (c) of this section. The system must provide written notification to the executive director that it provides at least 4-log treatment of viruses at or before the first customer. The notification must include engineering, operational, and other information required by the executive director to evaluate the submission. If the system discontinues 4-log treatment of viruses before or at the first customer for a groundwater source, the system must conduct raw groundwater source sampling as required under subsection (c)(4) of this section.

2. (b) Groundwater corrective action plan. All public water systems using groundwater must submit a corrective action plan and implement corrective action if a raw groundwater source sample was positive for fecal indicators.

   1. (1) If a groundwater source sample was found to be fecal indicator positive, the system must consult with the executive director regarding appropriate corrective action and have an approved corrective action plan in place within 30 days of receiving written notification from a laboratory of the fecal indicator positive source sample collected under subsection (c)(4) of this section.
   2. (2) Within 120 days of receiving written notification from a laboratory of the fecal indicator positive source sample, the system must have completed corrective action or be in compliance with an approved corrective action plan and schedule.
   3. (3) Any changes to the approved corrective action plan or schedule must be approved by the executive director.
   4. (4) The executive director may require interim measures for the protection of public health pending approval of the corrective action plan. The system must comply with these interim measures as well as with any schedules specified by the executive director.

   5. (5) Systems that are required to complete corrective action must implement one or more of the procedures in this paragraph and the details of the implementation must be specified in the approved corrective action plan.

      1. (A) The system may disinfect the groundwater source where the fecal indicator positive source sample was collected following the American Water Works Association (AWWA) standards for well disinfection and start monthly fecal indicator sampling at that source within 30 days after well disinfection. The executive director may discontinue the monthly source sampling requirement if corrective action is sufficient.
      2. (B) The system may eliminate the source that was found to be fecal indicator positive and provide an alternate source if necessary. Eliminated sources must be disconnected from the distribution system.
      3. (C) The system may identify and eliminate the source of fecal contamination followed by well disinfection according to AWWA well disinfection standards and begin monthly fecal indicator sampling within 30 days after well disinfection. The executive director may allow the system to discontinue the monthly source sampling requirement after making a determination that corrective action is sufficient.
      4. (D) The system may provide treatment that reliably achieves at least 4-log treatment of viruses using inactivation, removal or an executive director-approved combination of inactivation and removal before the first customer of the groundwater source.

3. (c) Microbial inactivation requirements. A system that treats groundwater in response to a fecal indicator positive source sample or in lieu of the raw groundwater source monitoring shall meet minimum disinfection requirements demonstrating at least 4-log treatment of viruses before the water is distributed.

   1. (1) Monitoring requirements for chemical disinfectants. Groundwater systems shall monitor the performance of the disinfection facilities to ensure that appropriate disinfectant levels are maintained. All monitoring conducted pursuant to the requirements of this section must be conducted at sites designated in the system's monitoring plan.

      1. (A) Groundwater systems serving a population greater than 3,300 must continuously monitor the residual disinfectant concentration at a location approved by the executive director and must record the lowest residual disinfectant concentration every day the groundwater source serves the public.
      2. (B) Groundwater systems serving a population less than 3,300 must monitor the disinfectant residual in each disinfection zone at least once each day during a time when peak hourly raw water flow rates are occurring.
      3. (C) Disinfection contact time will be based on tracer study data or a theoretical analysis submitted by the system owner or their designated agent and approved by the executive director.
      4. (D) Groundwater treatment plants that fail to demonstrate an appropriate level of treatment must repeat these tests at four-hour or shorter intervals until compliance has been reestablished.
   2. (2) Monitoring requirements for ultraviolet light (UV) disinfection facilities. Public water systems shall monitor the UV intensity as measured by a UV sensor, lamp status, the flow rate through the unit, and other parameters prescribed by the executive director to ensure that the units are operating within validated conditions.

   3. (3) Analytical requirements. All monitoring required by this section must be conducted at a facility approved by the executive director and using methods that conform to the requirements of §290.119 of this title (relating to Analytical Procedures).

      1. (A) The pH analysis must be conducted using a pH meter with a minimum accuracy of plus or minus 0.1 pH units.
      2. (B) The temperature of the water must be measured using a thermometer or thermocouple with a minimum accuracy of plus or minus 0.5 degrees Celsius.

      3. (C) The free chlorine residual must be measured to a minimum accuracy of plus or minus 0.1 mg/L using one of the following methods:

         1. (i) Amperometric titration;
         2. (ii) DPD Ferrous titration;
         3. (iii) a DPD method that uses a colorimeter or spectrophotometer; or
         4. (iv) Springaldizine (FACTS)

      4. (D) The chloramine residual must be measured to a minimum accuracy of plus or minus 0.1 mg/L using one of the following methods:

         1. (i) Amperometric titration;
         2. (ii) DPD Ferrous titration; or
         3. (iii) a DPD method that uses a colorimeter or spectrophotometer.

      5. (E) The chlorine dioxide residual must be measured to a minimum accuracy of plus or minus 0.05 mg/L using one of the following methods:

         1. (i) Amperometric titrator with platinum-platinum electrodes; or
         2. (ii) Lissamine Green B.
      6. (F) The ozone residual must be measured to a minimum accuracy of plus or minus 0.05 mg/L using an indigo method that uses a colorimeter or spectrophotometer.

4. (d) Reporting requirements. Groundwater systems required to conduct corrective action in response to a fecal indicator positive source sample or in lieu of the raw groundwater source monitoring must report to the executive director in accordance with this subsection.

   1. (1) A groundwater system required to conduct compliance monitoring for chemical disinfectants must submit a Groundwater Treatment Monthly Operating Report (commission Form 20362) for groundwater disinfection facilities monthly. Groundwater systems must submit the first form starting before the month of December 2009, to avoid raw groundwater source monitoring.
   2. (2) A groundwater system must provide written notification to the executive director before December 1, 2009, that it is not required to meet the raw groundwater source monitoring requirements under paragraph §290.109(c)(4) of this title (relating to Microbial Contaminants) because it provides at least 4-log treatment of viruses and begin compliance monitoring in accordance with subsection §290.116(c) of this section. The notification must include engineering, operational, and other information required by the executive director to evaluate the submission.
   3. (3) A groundwater system required to complete corrective action under subsection (b) of this section must notify the executive director within 30 days of completing the corrective action.
   4. (4) If a groundwater system is subject to the triggered source monitoring requirements of §290.109(c)(4)(A) of this title and does not conduct source monitoring, the system must provide written documentation that it was providing 4-log treatment of viruses within 30 days of the positive distribution coliform sample.

5. (e) Compliance determination. The executive director shall determine compliance for groundwater systems required to conduct corrective action in response to a fecal indicator positive source sample or in lieu of the raw groundwater source monitoring in accordance with this subsection.

   1. (1) A groundwater system is in violation of the treatment technique requirement if it does not complete corrective action in accordance with the executive director-approved corrective action plan or any interim measures required by the executive director.
   2. (2) A groundwater system is in violation of the treatment technique requirement if it is not in compliance with the executive director-approved corrective action plan and schedule.
   3. (3) A groundwater system subject to the requirements of subsection §290.116(c) of this title that fails to maintain at least 4-log treatment of viruses is in violation of the treatment technique requirement if the failure is not corrected within four hours.
   4. (4) A groundwater system that fails to conduct the disinfectant monitoring required under subsection (c) of this section commits a monitoring violation.
   5. (5) A groundwater system that fails to report the results of the disinfectant monitoring required under subsection (c) of this section commits a reporting violation.
   6. (6) A groundwater system that fails to issue a required public notice or certify that the public notice has been performed commits a public notice violation.
6. (f) Public notification. A groundwater system that commits a treatment technique, monitoring, or reporting violation as identified in this section must notify its customers of the violation in accordance with the requirements of §290.122 of this title (relating to Public Notification).

Source Note:The provisions of this §290.116 adopted to be effective January 9, 2008, 33 TexReg 198.