Rule 391-3-5-.24 - Disinfectant Residuals, Disinfection Byproducts, and Disinfection Byproduct Precursors Sampling, Analytical and Other Requirements(1)Purpose. The purpose of this Rule is to provide for the procedures for establishing maximum contaminant levels, monitoring and other requirements for trihalomethanes, disinfectant residuals, disinfection byproducts, and disinfection byproduct precursors.(2)Variances. Variances from the maximum contaminant level for total trihalomethanes shall be conducted in accordance with 40 CFR § 142.60.(3)Disinfectant Residuals, Disinfection Byproducts, and Disinfection Byproduct Precursors.(a) Community water systems and non-transient, non-community water systems which add a chemical disinfectant to the water in any part of the drinking water treatment process must modify their practices to meet MCLs and MRDLs specified in subparagraph (7)(a) of Rule 391-3-5-.18, and must meet the treatment technique requirements for disinfection byproduct precursors specified in paragraph (10).(b) Transient non-community water systems that use chlorine dioxide as a disinfectant or oxidant must modify their practices to meet the MRDL for chlorine dioxide specified in subparagraph (7)(a) of Rule 391-3-5-.18.(c) Community Subpart H water systems and non-transient, non-community Subpart H water systems must comply with the requirements of this Rule, as specified in paragraphs (7)(b) and (7)(c) of Rule 391-3-5-.18, respectively.(d) Beginning January 1, 2002, transient non-community Subpart H water systems serving 10,000 or more persons and using chlorine dioxide as a disinfectant or oxidant must comply with the requirements for chlorine dioxide and chlorite in this Rule.(e) Beginning January 1, 2004, transient non-community Subpart H water systems serving fewer than 10,000 people and using chlorine dioxide as a disinfectant or oxidant and systems using only ground water not under the direct influence of surface water and using chlorine dioxide as a disinfectant or oxidant must comply with the requirements for chlorine dioxide and chlorite in this Rule.(f) Systems may increase residual disinfectant levels in the distribution system of chlorine or chloramines (but not chlorine dioxide) to a level and for a time necessary to protect public health, to address specific microbiological contamination problems caused by circumstances such as, but not limited to, distribution line breaks, storm run-off events, source water contamination events, or cross-connection events.(g) Systems must use the analytical method(s) specified in 40 CFR § 141.131 to demonstrate compliance with the requirements of this Rule. The analytical requirements specified in 40 CFR § 141.131, which is hereby incorporated by reference, are required to demonstrate compliance with the requirements of Subpart L (Disinfectant Residuals, Disinfection ByProducts, and Disinfection ByProduct Precursors), Subpart U (Initial Distribution System Evaluations), and Subpart V (Stage 2 Disinfection ByProducts Requirements) of 40 CFR Part 141 .(h) Monitoring Requirements. 40 CFR § 141.132, in its entirety, is hereby incorporated by reference. For compliance with the requirements of this Rule, the water systems must monitor the applicable parameters included in this Rule at the frequency specified in 40 CFR § 141.132. Failure to monitor will be treated as a violation for the entire period covered by the annual average where compliance is based on a running annual average of monthly or quarterly samples or averages and the system's failure to monitor makes it impossible to determine compliance with MCLs or MRDLs.1. Systems must take all samples during normal operating conditions.2. Systems may consider multiple wells drawing water from a single aquifer as one treatment plant for determining the minimum number of TTHM and HAA5 samples required, with the Division approval.3. Systems may use only data collected under the provisions of this Rule to qualify for reduced monitoring.4. Each system required to monitor under this Rule must develop and implement a monitoring plan. The plan must include at least the following elements: specific locations and schedules for collecting samples for any parameters included in this Rule; how the system will calculate compliance with MCLs, MRDLs, and treatment techniques; and if approved for monitoring as a consecutive system, or if providing water to a consecutive system, the sampling plan must reflect the entire distribution system. (i) The system must maintain the plan and make it available for inspection by the Division and the general public no later than thirty (30) days following applicable compliance dates stated in paragraph (3)(c).(ii) All Subpart H systems serving more than 3,300 people must submit a copy of the monitoring plan to the Division no later than the date of the first report required under 40 CFR § 141.134.(iii) The Division may require a monitoring plan to be submitted by any other system. The Division may also require changes in any plan elements.(4)Monitoring and Compliance for Disinfection Byproducts. Monitoring for disinfection byproducts shall be conducted as specified in 40 CFR § 141.132(b). Compliance with the disinfection byproducts requirements shall be determined in accordance with 40 CFR § 141.133(b).(5)Monitoring and Compliance for Disinfectant Residuals.(a) Monitoring for disinfectant residuals shall be conducted as specified in 40 CFR § 141.132(c). Compliance with the disinfectant residuals requirements shall be determined in accordance with 40 CFR § 141.133(c).(b)Routine monitoring. Until March 31, 2016, community and non-transient non-community water systems that use chlorine or chloramines must measure the residual disinfectant level in the distribution system at the same point in the distribution system and at the same time as total coliforms are sampled, as specified in 40 CFR § 141.21. Beginning April 1, 2016, community and non-transient non-community water systems that use chlorine or chloramines must measure the residual disinfectant level in the distribution system at the same point in the distribution system and at the same time as total coliforms are sampled, as specified in Rule 391-3-5-.55(4) through (8). 40 CFR Part 141 Subpart H systems may use the results of residual disinfectant concentration sampling conducted under 40 CFR § 141.74(c)(3)(i) for systems which filter, in lieu of taking separate samples.(6)Monitoring and Compliance for Disinfection Byproduct Precursors. Monitoring for disinfection byproduct precursors shall be conducted as specified in 40 CFR § 141.132(d). Compliance with the disinfection byproduct precursors requirements shall be determined in accordance with 40 CFR § 141.133(c) and as specified by 40 CFR § 141.135(b).(7)Non-Compliance in First Monitoring Year. If, during the first year of monitoring under 40 CFR § 141.132, any individual quarter's average will cause the running annual average of that system to exceed the MCL, the system shall be considered out of compliance at the end of that quarter.(8)Samples for Compliance Determination. All samples taken and analyzed under the provisions of this Rule must be included in determining compliance, even if that number is greater than the minimum required. Compliance requirements specified in 40 CFR Part 141, Subpart L § 141.133 is hereby incorporated by reference.(9)Treatment Techniques. Treatment techniques for control of disinfection byproduct precursors requirements specified in 40 CFRPart 141, Subpart L § 141.135 is hereby incorporated by reference. (a) Subpart H systems using conventional filtration treatment (as defined in § 141.2) must operate with enhanced coagulation or enhanced softening to achieve the TOC percent removal levels specified in 40 CFR § 141.135(b) unless the system meets at least one of the alternative compliance criteria specified in 40 CFR §§ 141.135(a)(2) or (a)(3).(b) Alternative compliance criteria for enhanced coagulation and enhanced softening systems: 40 CFR Part 141, Subpart L § 141.135(a)(2) is hereby incorporated by reference.(c) Additional alternative compliance criteria for softening systems: 40 CFR Part 141, Subpart L, § 141.135(a)(3) is hereby incorporated by reference.(d) Enhanced coagulation and enhanced softening performance requirements: 40 CFR Part 141, Subpart L § 141.135(b) is hereby incorporated by reference.(e) Compliance calculations: 40 CFR Part 141, Subpart L § 141.135(c) is hereby incorporated by reference.(f) Treatment technique requirements for disinfection byproduct precursors: 40 CFR Part 141, Subpart L § 141.135(d) is hereby incorporated by reference.(g) Required additional health information: 40 CFR § 141.154 is hereby incorporated by reference.Ga. Comp. R. & Regs. R. 391-3-5-.24
O.C.G.A. § 12-5-170 et seq.
Original Rule entitled "Laboratory Approval" adopted. F. July 5, 1977; eff. July 26, 1977, as specified by Rule 391-3-5-.47.Repealed: New Rule of same title adopted. F. July 15, 1983; eff. August 4, 1983.Repealed: New Rule entitled "Trihalomethanes" adopted. F. May 12, 1989; eff. June 1, 1989.Amended: F. Dec. 4, 1990; eff. Dec. 24, 1990.Repealed: New Rule entitled "Total Trihalomethanes Sampling. Analytical and Other Requirements" adopted. F. June 25, 1992; eff. July 15, 1992.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. May 29, 2009; eff. June 16, 2009.Amended: New title "Disinfection Byproducts Sampling, Analytical and Other Requirements. Amended." F. Jan. 8, 2014; eff. Jan. 28, 2014.Amended: New title "Disinfectant Residuals, Disinfection Byproducts, and Disinfection Byproduct Precursors Sampling, Analytical and Other Requirements." F. Feb. 29, 2016; eff. Mar. 20, 2016.Amended: F. Apr. 22, 2021; eff. May 12, 2021.