A public water system that uses a surface water source must provide filtration treatment which complies with this section by July 1, 1993. A public water system that uses groundwater under the direct influence of surface water must provide filtration by a date specified by the commission. Such date will not exceed 18 months from the date of notification. Failure to meet any requirement of this section after the applicable date specified in this section is a treatment technique violation. Violation of any treatment technique requirement of this section must be reported to the commission by the end of the next business day after the measurement was taken.

1. (1) For systems using conventional filtration or groundwater systems under the influence of surface water using direct filtration, the turbidity level of representative samples of a system's filtered water must be less than or equal to 0.5 Nephelometric Turbidity Unit (NTU) in at least 95% of the measurements taken each month, measured as specified in §290.119 of this title (relating to Monitoring Requirements Relating to Turbidity and Disinfection for Systems Using Surface Water Treatment); except that if the commission determines that the system is capable of achieving at least 99.9% removal and/or inactivation of Giardia lamblia cysts at some turbidity level higher than 0.5 NTU in at least 95% of the measurements taken each month, the commission may substitute this higher turbidity limit for that system. However, in no case may the commission approve a turbidity limit that allows more than 1.0 NTU in more than 5.0% of the samples taken each month.
2. (2) The turbidity level of representative samples of a system's filtered water must at no time exceed 5.0 NTU.

Source Note:The provisions of this §290.118 adopted to be effective April 15, 1994, 19 TexReg 2282.