Texas Administrative Code › Title 30 - ENVIRONMENTAL QUALITY › Part 1 - TEXAS COMMISSION ON ENVIRONMENTAL QUALITY › Chapter 290 - PUBLIC DRINKING WATER › Subchapter F - DRINKING WATER STANDARDS GOVERNING DRINKING WATER QUALITY AND REPORTING REQUIREMENTS FOR PUBLIC WATER SYSTEM › Section 290.114 - Other Disinfection Byproducts (Chlorite and Bromate)

Current through Reg. 49, No. 28; July 12, 2024
(a) Chlorite. All public water systems that
				  use chlorine dioxide must comply with the requirements of this subsection.
(1) Maximum contaminant level (MCL) for
				  chlorite. The chlorite concentration in the water in the distribution system
				  shall not exceed an MCL of 1.0 milligrams per liter (mg/L).
(2) Monitoring requirements for chlorite.
				  Public water systems shall measure the chlorite concentration at locations and
				  intervals specified in the system's monitoring plan. All samples must be
				  collected during normal operating conditions.
(A) Each plant using chlorine dioxide must
				  monitor the chlorite concentration in the water entering the distribution
				  system at least once each day. The monitoring frequency at the entry point to
				  the distribution system may not be reduced.
(B) Each plant using chlorine dioxide must
				  monitor the chlorite concentration in the water within the distribution system
				  at each of the following three locations: at a location near the first customer
				  of a plant using chlorine dioxide; at a location representative of the average
				  residence time in the distribution system; and at a location reflecting maximum
				  residence time in the distribution system. The group of three samples must be
				  collected on the same day and is called a "three-sample set."
(i) Each system must collect at least one
				  three-sample set each month.
(ii)
				  If the chlorite concentration entering the distribution system exceeds 1.0
				  mg/L, the system must collect a three-sample set within 24 hours.
(iii) The frequency of chlorite monitoring in
				  the distribution system may be reduced to one three-sample set per quarter if
				  none of the entry point or distribution system samples tested during the
				  preceding 12 months contained a chlorite concentration above 1.0 mg/L. A system
				  must revert to the monthly monitoring frequency if the chlorite concentration
				  exceeds 1.0 mg/L in any sample.
(3) Analytical requirements for chlorite.
				  Analytical procedures required by this section shall be performed in accordance
				  with the requirements of §
											290.119 of
				  this title (relating to Analytical Procedures).
(A) The chlorite concentration of the water
				  entering the distribution system must be analyzed at a facility approved by the
				  executive director. The analysis must have a minimum accuracy of 0.05
				  mg/L.
(B) The chlorite
				  concentration of the water within the distribution system must be analyzed
				  using ion chromatography at a facility accredited by the executive
				  director.
(4) Reporting
				  requirements for chlorite. Public water systems that are subject to the
				  provisions of this subsection must ensure the executive director is provided
				  with the results of any test, measurement, or analysis required by this
				  section.
(A) Systems using chlorine dioxide
				  must submit a Chlorine Dioxide Monthly Operating Report (commission Form 0690)
				  by the tenth day of the month following the end of the reporting
				  period.
(B) Except where a shorter
				  period is specified in this section, a public water system shall ensure the
				  executive director is provided with a copy of the results of any chlorite test,
				  measurement, or analysis required by paragraph (2)(B) of this subsection within
				  the first ten days following the end of the required monitoring period or ten
				  days following receipt of the results of such test, measurement, or analysis
				  whichever occurs first.
(C) Reports
				  and analytical results must be mailed to the Water Supply Division, MC 155,
				  Texas Commission on Environmental Quality, P.O. Box 13087, Austin, Texas
				  78711-3087.
(5)
				  Compliance determination for chlorite. Compliance with the requirements of this
				  subsection shall be based on the following criteria.
(A) A public water system that fails to
				  conduct the monitoring tests required by this subsection commits a monitoring
				  violation.
(B) A public water
				  system that fails to report the results of the monitoring tests required by
				  this subsection commits a reporting violation.
(C) A public water system commits an MCL
				  violation if the arithmetic average of any three-sample set collected in the
				  distribution system exceeds the MCL for chlorite.
(D) A public water system that fails to do a
				  required public notice or certify that the public notice has been performed
				  commits a public notice violation.
(6) Public notification requirements for
				  chlorite. A public water system that violates the requirements of this
				  subsection must notify the executive director and the system's customers.
(A) A public water system that violates the
				  MCL for chlorite shall notify the executive director by the end of the next
				  business day and the customers in accordance with the requirements of §
												290.122(b)
				  of this title (relating to Public Notification).
(B) A public water system which fails to
				  conduct the monitoring required by this subsection must notify its customers of
				  the violation in accordance with the requirements of §
												290.122(c)
				  of this title.