Rule 391-3-5-.20. Turbidity Sampling and Analytical Requirements.

Georgia Administrative Code

Department 391. RULES OF GEORGIA DEPARTMENT OF NATURAL RESOURCES

Chapter 391-3. ENVIRONMENTAL PROTECTION

Subject 391-3-5. RULES FOR SAFE DRINKING WATER

Current through Rules and Regulations filed through July 9, 2019

Rule 391-3-5-.20. Turbidity Sampling and Analytical Requirements

(1) Turbidity Testing Frequency. On and after June 29, 1993, representative samples of filtered water shall be taken and analyzed by said suppliers at least every four hours when the plant is in operation, for the purpose of making turbidity measurements to determine compliance with the treatment technique requirement of paragraph (3) of Section 391-3-5-.18. If the Division determines that a reduced sampling frequency in a non-community system will not pose a risk to public health, it can reduce the required sampling frequency in accordance with 40 CFR 141.74 for systems using slow sand filtration or filtration treatment other than conventional treatment, direct filtration, or diatomaceous earth filtration. 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 Division has indicated in writing that no unreasonable risk to health existed under the circumstances of this option. The turbidity measurements shall be made in accordance with the recommendations set forth in 40 CFR Part 141.22.
(2) Exceedance Determination. If the result of a turbidity analysis on and after June 29, 1993 indicates that the treatment technique requirement 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 treatment technique requirement has been exceeded, the supplier of water shall consult with the primacy agency within 24 hours after learning about the violation (141.203(b)). If consultation does not occur within those 24 hours the violation is elevated to a Tier 1. The repeat sample shall be the sample of water used for the purpose of calculating compliance with the monthly treatment technique requirement. If the monthly treatment technique requirement is exceeded, or if the maximum measured level exceeds the maximum allowable level, the supplier of water shall report to the Division and notify the public as directed in Sections 391-3-5-.30 and .32.
(3) Applicability to Surface Water Sources. The requirements of this Section shall apply only to public water systems, which use water obtained in whole or in part from surface water sources or ground water sources under the direct influence of surface water.
(4) Compliance and Enforcement. The Division has the authority to determine compliance or initiate enforcement action based upon analytical results or other information compiled by their sanctioned representatives or agencies.
(5) Filtration Requirements for Greater than 10,000 Population Water Systems. Beginning January 1, 2002, public water systems that use surface water or ground water under the direct influence of surface water and serve at least 10,000 people must meet the filtration requirements specified in 40 CFR § 141.173.
(6) Enhanced Filtration Requirements. The Enhanced Filtration and Disinfection requirements specified in 40 CFR, Subpart P are applicable to Subpart H systems serving at least 10,000 people.
(a) General requirements: 40 CFR, Subpart P § 141.170 is hereby incorporated by reference. Subpart H systems that did not conduct optional monitoring under § 141.172 because they served fewer than 10,000 persons when such monitoring was required, but serve more than 10,000 persons prior to January 14, 2005 must comply with §§ 141.170, 141.171, 141.173, 141.174, and 141.175. These systems must contact the Division and establish a disinfection benchmark. A system that decides to make a significant change to its disinfection practice, as described in § 141.172(c)(1)(i) through (iv) must obtain prior approval from the Division prior to making such change.
(b) Criteria for avoiding filtration: 40 CFR, Subpart P § 141.171 is hereby incorporated by reference.
(c) Disinfection profiling and benchmarking: 40 CFR, Subpart P § 141.172 is hereby incorporated by reference.
(d) Determination of systems required to profile: 40 CFR, Subpart P § 141.172(a) is hereby incorporated by reference.
(e) Disinfection profiling: 40 CFR, Subpart P § 141.172(b) is hereby incorporated by reference.
(f) Disinfection benchmarking: 40 CFR, Subpart P § 141.172(c) is hereby incorporated by reference.
(7) Filtration. 40 CFR, Subpart P § 141.173 is hereby incorporated by reference.
(a) Conventional filtration treatment or direct filtration: 40 CFR, Subpart P § 141.173(a) is hereby incorporated by reference. (For systems using conventional filtration or direct filtration, the turbidity level of representative samples of a system's filtered water must be less than or equal to 0.3 NTU (Nephelometric Turbidity Units) in at least 95 percent of the measurements taken each month, measured as specified in 40 CFR § 141.74(a) and (c), and the turbidity level of representative samples of a system's filtered water must at no time exceed 1 NTU, measured as specified in 40 CFR § 141.74(a) and (c) ).
(b) Systems using filtration technologies other than conventional filtration treatment, direct filtration, slow sand filtration, or diatomaceous earth filtration: 40 CFR, Subpart P § 141.173(b) is hereby incorporated by reference. Beginning January 1, 2002, systems serving at least 10,000 people must meet the requirements for other filtration technologies referenced in 141.173(b).
(c) Filtration sampling requirements: 40 CFR, Subpart P § 141.174 is hereby incorporated by reference. (A public water system subject to the requirements of this section that provides conventional filtration treatment or direct filtration must conduct continuous monitoring of turbidity for each individual filter using an approved method in 40 CFR § 141.74(a) and must calibrate turbidimeters using the procedure specified by the manufacturer. Systems must record the results of individual filter monitoring every fifteen (15) minutes. If there is a failure in the continuous turbidity monitoring equipment, the system must conduct grab sampling every four (4) hours in lieu of continuous monitoring, but for no more than five (5) working days following the failure of the equipment.)
(8) Filtration Requirements for Fewer than 10,000 Population Water Systems. Beginning January 14, 2005, public water systems that use surface water or ground water under the direct influence of surface water as a source and serve fewer than 10,000 people must meet the filtration and disinfection requirements in 40 CFR Part 141, Subpart T. This requirement is in addition to complying with requirements in Subpart H of 40 CFR Part 141.
(a) Beginning January 14, 2005, public water systems that use surface water or ground water under the direct influence of surface water and serve fewer than 10,000 people must meet the filtration requirements specified in 40 CFR §§ 141.550 through 141.553.
(b) Other filtration technologies: 40 CFR § 141.73(d) is hereby incorporated by reference. Beginning January 14, 2005, systems serving fewer than 10,000 people must meet the requirements for other filtration technologies in 40 CFR §§ 141.550 through 141.553.
(c) General requirements: 40 CFR, Subpart T § 141.500 is hereby incorporated by reference.
(d) Additional watershed control requirements for unfiltered systems: 40 CFR, Subpart T §§ 141.520 through 141.522 is hereby incorporated by reference. This is in addition to the continued requirement to comply with the filtration avoidance criteria in 40 CFR § 141.71.
(e) Disinfection Profile: 40 CFR, Subpart T §§ 141.530 through 141.536 is hereby incorporated by reference. This requirement applies both to community and non-transient non-community water systems.
(f) Disinfection benchmark: 40 CFR, Subpart T §§ 141.540 through 141.544 is hereby incorporated by reference. If you are a subpart H system required to develop a disinfection profile under Section 391-3-5-.20(10)(e) , your system must develop a disinfection benchmark if you decide to make a significant change to your disinfection practice. Before implementing a significant disinfection practice change, a prior approval from the Division must be obtained. Significant changes to disinfection practice include:
1. Changes to the point of disinfection;
2. Changes to the disinfectant(s) used in the treatment plant;
3. Changes to the disinfection process; or
4. Any other modification identified by the Division.
(g) Combined filter effluent requirements: 40 CFR, Subpart T § 141.550 through 141.553 is hereby incorporated by reference. This requirement applies to all subpart H systems which serve populations fewer than 10,000, are required to filter, and utilize filtration other than slow sand filtration or diatomaceous earth filtration.
1. For systems using conventional filtration or direct filtration, the turbidity level of representative samples of a system's filtered water must be less than or equal to 0.3 NTU in at least 95 percent of the measurements taken each month, and the maximum turbidity level of representative samples of a system's filtered water must at no time exceed 1 NTU. All measurements must be taken as described in 40 CFR § 141.74(a) and (c).
2. For systems using "alternative" filtration (filtration other than slow sand filtration, diatomaceous earth filtration, conventional filtration, or direct filtration), the 95th percentile turbidity value, not to exceed 1 NTU, and the maximum turbidity value, not to exceed 5 NTU, shall be determined by the Division based on the demonstration as described in 40 CFR, Subpart T § 141.552. The systems, using pilot plant studies or other means, must demonstrate that the system's filtration, in combination with disinfection treatment, consistently achieves: two-log (99%) removal of Cryptosporidium oocysts; three-log (99.9%) removal and/or inactivation of Giardia lamblia cysts; and four-log (99.99%) removal and/or inactivation of viruses.
(h) Individual filter turbidity requirements for systems utilizing conventional filtration or direct filtration: 40 CFR, Subpart T §§ 141.560 through 141.564 is hereby incorporated by reference. A subpart H public water system subject to the requirements of this section must conduct continuous monitoring of turbidity for each individual filter using an approved method in 40 CFR § 141.74(a) and must calibrate turbidimeters using the procedure specified by the manufacturer. Systems must record the results of individual filter monitoring every fifteen (15) minutes. If there is a failure in the continuous turbidity monitoring equipment, the system must conduct grab sampling every four (4) hours in lieu of continuous monitoring until the turbidimeter is back on-line. The system has fourteen (14) days to resume continuous monitoring before a violation is incurred.
1. Systems with two or fewer filters may conduct continuous monitoring of combined filter effluent turbidity in lieu of individual filter effluent turbidity monitoring, in accordance with the same requirements set forth in 40 CFR § 141.560(a) through (d) and § 141.561.
2. Based on continuous turbidity monitoring of individual filters, the systems are required to take the follow-up actions described in 40 CFR § 141.563(a), (b) and (c).
(i) Reporting and recordkeeping requirements: 40 CFR, Subpart T §§ 141.570 through 141.571 is hereby incorporated by reference. The items which must be reported and the frequency of reporting must be as specified in 40 CFR § 141.570. Based on the requirements of subpart T of 40 CFR Part 141, applicable systems must keep several required records, in addition to the recordkeeping required under 40 CFR § 141.75. Specifically, the results of individual filter monitoring must be kept for at least three (3) years and the results of any disinfection profiling or benchmarking (including raw data and analysis) must be kept indefinitely.

Cite as Ga. Comp. R. & Regs. R. 391-3-5-.20

Authority: O.C.G.A. Sec. 12-5-170 et seq.

History. Original Rule entitled "Enforcement" adopted. F. Sept. 6, 1973; eff. Sept. 26, 1973.

Repealed: New Rule entitled "Turbidity Sampling and Analytical Requirements" adopted. F. July 5, 1977; eff. July 26, 1977, as specified by Rule 391-3-5-.47.

Amended: F. July 15, 1983; eff. Aug. 4, 1983.

Repealed: New Rule same title adopted. F. May 12, 1989; eff. June 1, 1989.

Repealed: New Rule of same title adopted. F. Dec. 4, 1990; eff. Dec. 24, 1990.

Amended: F. June 25, 1992; eff. July 15, 1992.

Repealed: New Rule of same title, adopted. F. Mar. 10, 1994; eff. Mar. 30, 1994.

Amended: F. Sept. 26, 1997; eff. Oct. 16, 1997.

Amended: F. Sept. 29, 2000; eff. Oct. 19, 2000.

Amended: F. June 8, 2001; eff. June 28, 2001.

Amended: F. Dec. 10, 2002; eff. Dec. 30, 2002.

Amended: F. Dec. 21, 2004; eff. Jan. 10, 2005.

Amended: New title "Turbidity Sampling and Analytical Requirements. Amended."F. Jan. 8, 2014; eff. Jan. 28, 2014.