Section 11-20-10 - Turbidity sampling and analytical requirements(a) Samples shall be taken by suppliers of water for public water systems using surface water sources in whole or in part. Turbidity measurements shall be made by the Nephelometric Method 2130B cited in the 18th edition of Standard Methods for the Examination of Water and Wastewater, 1992, or by the methods cited in 40 C.F.R. § 141.74(a)(1).(b) The requirements in this subsection apply to filtered surface water systems until June 29, 1993. The requirements in this subsection apply to unfiltered systems until June 29, 1993, or until filtration is installed, whichever is later. The director shall determine, in writing pursuant to 42 U.S.C. § 300g-1(b)(7)(C)(iii), which systems must install filtration. (1) Samples shall be taken by suppliers of water for public water systems using surface water sources in whole or in part. Samples shall be taken at a representative entry point(s) to the water distribution system at least once per day, for the purpose of making turbidity measurements to determine compliance with section 11-20-5. If the director determines that a reduced sampling frequency in a non-community system will not pose a risk to public health, the director may reduce the required sampling frequency. The option of reducing the turbidity frequency shall be permitted only in those public water systems that practice disinfection and which maintain an active residual disinfectant in the distribution system, and in those cases where the director has indicated in writing that no unreasonable risk to health existed under the circumstances of this option. (2) If the result of a turbidity analysis indicates that the maximum allowable limit has been exceeded, the sampling and measurement shall be confirmed by resampling as soon as practicable and preferably within one hour. If the repeat sample confirms that the maximum allowable limit has been exceeded, the supplier of water shall report to the director within forty-eight hours. The repeat sample shall be the sample used for the purpose of calculating the monthly average. If the monthly average of the daily samples exceeds the maximum allowable limit, or if the average of two samples taken on consecutive days exceeds five NTU, the supplier of water shall report to the director and notify the public as directed in sections 11-20-17 and 11-20-18.(c) After June 29, 1993, samples shall be collected at the filtration plant effluent or immediately prior to entry into the distribution system. Sampling of the plant effluent is acceptable if there are no storage tanks between the sampling point and entry into the distribution system. Continuous monitoring with a turbidimeter and recording chart, or collection of grab samples every four hours is required for conventional treatment, direct, and diatomaceous earth filtration.[Eff 12/26/81; am and comp 3/7/92; am and comp 1/2/93; am and comp 12/15/94; am and comp 10/13/97; comp 9/7/99; comp 11/30/02; comp 12/16/05; comp 11/28/11; comp MAY 02 2014 ] (Auth: HRS §§ 340E-2, 340E-9) (Imp: HRS §§ 340E-2, 340E-9; 42 U.S.C. §§ 300g-1, 300g-2; 40 C.F.R. Parts 141, 142, § 141.22, § 142.10 )