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TITLE 30ENVIRONMENTAL QUALITY
PART 1TEXAS COMMISSION ON ENVIRONMENTAL QUALITY
CHAPTER 290PUBLIC DRINKING WATER
SUBCHAPTER DRULES AND REGULATIONS FOR PUBLIC WATER SYSTEMS
RULE §290.46Minimum Acceptable Operating Practices for Public Drinking Water Systems

      (ii) a waterborne disease outbreak, as defined in 40 Code of Federal Regulations §141.2, or other waterborne emergencies for situations that do not meet this definition, but that still have the potential to have serious adverse effects on health as a result of short-term exposure. These could include outbreaks not related to treatment deficiencies, as well as situations that have the potential to cause outbreaks, such as failures or significant interruption in water treatment processes, natural disasters that disrupt the water supply or distribution system, chemical spills, or unexpected loading of possible pathogens into the source water; or

      (iii) the public water system has failed to maintain adequate disinfectant residuals as described in subsection (d) of this section and as described in §290.110 of this title.

    (B) The executive director will provide written notification to the public water system in the event a public water system is required to institute special precautions, protective measures, or issue boil water notices to customers at the discretion of the executive director. Upon written notification from the executive director, the public water system shall implement special precautions, protective measures, or issue boil water notices to customers within 24 hours or within the time period specified by the executive director.

    (C) The public water system shall provide any required information to the executive director to document that the public water system has met the requirements for special precautions, protective measures, and boil water notices required at the discretion of the executive director under this paragraph.

  (6) Required actions prior to rescinding a boil water notice. A public water system shall notify customers throughout the distribution system or in the affected area(s) of the distribution system that a boil water notice has been rescinded after the public water system has met the requirements of this paragraph. A boil water notice issued under the requirements of this subsection shall remain in effect until the public water system has provided required compliance documentation to the executive director which establishes that the public water system has met the following requirements, as applicable:

    (A) water distribution system pressures in excess of 20 psi are consistently being maintained throughout the distribution system in accordance with the flowchart found in §290.47(e) of this title;

    (B) affected area(s) of the distribution system have been thoroughly flushed until a minimum of 0.2 mg/L free chlorine residual or 0.5 mg/L chloramine residual (measured as total chlorine) is present and is consistently being maintained in each finished water storage tank and throughout the distribution system as described in subsection (d) of this section;

    (C) finished water entering the distribution system, produced by a treatment plant that is treating surface water or groundwater under the direct influence of surface water, has a turbidity level that is consistently being maintained below 1.0 NTU;

    (D) actions required by the executive director under paragraph (5) of this subsection have been met and the public water system is operating in accordance with §290.111(h)(2) of this title as described in paragraph (5)(A)(i) of this subsection; and

    (E) water samples for microbiological analysis, marked as "special" on the laboratory sample submission form, were collected from representative locations throughout the distribution system or in the affected area(s) of the distribution system after the public water system has met all other applicable requirements of this paragraph and the water samples collected for microbiological analysis are found negative for coliform organisms. The water samples described in this subparagraph shall be analyzed at laboratories in accordance with §290.119 of this title (relating to Analytical Procedures).

    (F) A public water system shall notify customers throughout the distribution system or in the affected area(s) of the distribution system that a boil water notice has been rescinded within 24 hours or no later than the next business day, using the language and format specified in Figure: 30 TAC §290.47(c)(3) of this title, once the public water system has met the requirements of this paragraph. The public water system shall provide a copy of the "Boil Water Notice Rescinded" notice and a copy of the associated microbiological laboratory analysis results, as required by subparagraph (E) of this paragraph, to the executive director within ten days after the public water system has issued the rescind notice to customers in accordance with §290.122(f) of this title.

(r) Minimum pressures. All public water systems shall be operated to provide a minimum pressure of 35 psi throughout the distribution system under normal operating conditions. The system shall also be operated to maintain a minimum pressure of 20 psi during emergencies such as fire fighting. As soon as safe and practicable following the occurrence of a natural disaster, a public water system that is an affected utility shall maintain a minimum of 35 psi throughout the distribution system during an extended power outage.

(s) Testing equipment. Accurate testing equipment or some other means of monitoring the effectiveness of any chemical treatment or pathogen inactivation or removal processes must be used by the system.

  (1) Flow-measuring devices and rate-of-flow controllers that are required by §290.42(b) and (d) of this title (relating to Water Treatment) shall be calibrated at least once every 12 months. Well meters required by §290.41(c)(3)(N) of this title shall be calibrated at least once every three years.

  (2) Laboratory equipment used for compliance testing shall be properly calibrated.

    (A) pH meters shall be properly calibrated.

      (i) Benchtop pH meters shall be calibrated according to manufacturer specifications at least once each day.

      (ii) The calibration of benchtop pH meters shall be checked with at least one buffer each time a series of samples is run, and if necessary, recalibrated according to manufacturer specifications.

      (iii) On-line pH meters shall be calibrated according to manufacturer specifications at least once every 30 days.

      (iv) The calibration of on-line pH meters shall be checked at least once each week with a primary standard or by comparing the results from the on-line unit with the results from a properly calibrated benchtop unit. If necessary, the on-line unit shall be recalibrated with primary standards.

    (B) Turbidimeters shall be properly calibrated.

      (i) Benchtop turbidimeters shall be calibrated with primary standards at least once every 90 days. Each time the turbidimeter is calibrated with primary standards, the secondary standards shall be restandardized.

      (ii) The calibration of benchtop turbidimeters shall be checked with secondary standards each time a series of samples is tested, and if necessary, recalibrated with primary standards.

      (iii) On-line turbidimeters shall be calibrated with primary standards at least once every 90 days.

      (iv) The calibration of on-line turbidimeters shall be checked at least once each week with a primary standard, a secondary standard, or the manufacturer's proprietary calibration confirmation device or by comparing the results from the on-line unit with the results from a properly calibrated benchtop unit. If necessary, the on-line unit shall be recalibrated with primary standards.

    (C) Chemical disinfectant residual analyzers shall be properly calibrated.

      (i) The accuracy of manual disinfectant residual analyzers shall be verified at least once every 90 days using chlorine solutions of known concentrations.

      (ii) The accuracy of continuous disinfectant residual analyzers shall be checked at least once every seven days with a chlorine solution of known concentration or by comparing the results from the on-line analyzer with the result of approved benchtop method in accordance with §290.119 of this title.

      (iii) If a disinfectant residual analyzer produces a result which is not within 15% of the expected value, the cause of the discrepancy must be determined and corrected and, if necessary, the instrument must be recalibrated.

    (D) Analyzers used to determine the effectiveness of chloramination in §290.110(c)(5) of this title shall be properly verified in accordance with the manufacturer's recommendations every 90 days. These analyzers include monochloramine, ammonia, nitrite, and nitrate equipment used by the public water system.

    (E) Ultraviolet (UV) light disinfection analyzers shall be properly calibrated.

      (i) The accuracy of duty UV sensors shall be verified with a reference UV sensor monthly, according to the UV sensor manufacturer.

      (ii) The reference UV sensor shall be calibrated by the UV sensor manufacturer on a yearly basis, or sooner if needed.

Cont'd...

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