401 KAR 8:510. Disinfectant residuals, disinfection by-products, and disinfection by-product precursors.

401 KAR 8:510. Disinfectant residuals, disinfection by-products, and disinfection by-product precursors.

RELATES TO: KRS 224.10-100, 224.10-110, 40 C.F.R. 142.60

STATUTORY AUTHORITY: KRS 224.10-100(30), 224.10-110(2), 40 C.F.R. 141.30, 141.64, 141.65, 141.130-141.135, 42 U.S.C. Chapter 6A Subchapter XII

NECESSITY, FUNCTION, AND CONFORMITY: KRS 224.10-100(30) and 224.10-110(2) authorize the Environmental and Public Protection Cabinet to enforce administrative regulations promulgated by the secretary for the regulation and control of the purification of water for public and semipublic use. This administrative regulation establishes the maximum contaminant levels for total trihalomethanes and halocetic acid five (5) to limit the levels of known and unknown disinfection by-products.

Section 1. Applicability. (1) This administrative regulation shall be considered a national primary drinking water regulation.

(2) This administrative regulation establishes criteria under which:

(a) A community water system or a nontransient noncommunity water system that adds a chemical disinfectant as a part of the drinking water treatment process shall:

1. Modify its practices to meet maximum contaminant levels, or MCLs, and maximum residual disinfectant levels, or MRDLs, listed in Section 3 of this administrative regulation; and

2. Meet the treatment technique requirements for disinfection by-product precursors in Section 9 of this administrative regulation; and

(b) A transient noncommunity water system that uses chlorine dioxide as a disinfectant or oxidant shall modify its practices to meet the MRDL for chlorine dioxide in Section 3 of this administrative regulation.

(3) This administrative regulation establishes MCLs for TTHM and HAA5 and treatment technique requirements for disinfection by-product precursors to limit the levels of known and unknown disinfection by-products, which may have adverse health effects.

(4) Control of disinfectant residuals. The addition of a disinfectant is necessary for control of waterborne microbial contaminants. Notwithstanding the MRDLs in Section 3 of this administrative regulation, a system may increase the residual disinfectant level in the distribution system of chlorine or chloramines, except chlorine dioxide, to a level and for the amount of time necessary to protect public health, to address a specific microbiological contamination problem caused by circumstances such as:

(a) A distribution line break;

(b) Storm run-off event;

(d) Cross-connection event.

Section 2. Compliance Dates. (1) Community water system and nontransient noncommunity water system. Unless otherwise noted, a community water system or a nontransient noncommunity water system that uses as its source a surface water or groundwater under the direct influence of surface water shall comply with this administrative regulation.

(2) Transient noncommunity water system. A transient noncommunity water system that uses chlorine dioxide as a disinfectant or oxidant shall comply with the requirement for chlorine dioxide in this administrative regulation..

(3) Consecutive systems. Consecutive water systems shall monitor for trihalomethanes and HAA5 as follows:

(a) For purposes of determining the applicability and compliance dates, the sum of the populations of the system producing the water and the system purchasing the water shall be used.

(b) Producers.

1.a. A public water system that produces water and that provides water to another system shall be responsible for monitoring throughout the joint distribution system, which shall consist of the distribution systems of both the producing system and all purchasing systems.

b. Monitoring shall be performed pursuant to this administrative regulation at a point in the joint distribution system that reflects the longest period of retention.

2.a. If more than one (1) system produces water sold to a distribution system, monitoring shall be divided between or among the producing systems by a plan that reflects the likely flow of each producing system's water.

b. A monitoring plan for total trihalomethanes and HAA5s shall be submitted by all producing systems and shall be approved by the cabinet pursuant to Section 6(6) of this administrative regulation.

1.a. A system that purchases water shall alter distribution operation and maintenance practices necessary to alleviate any potential exceedance of the MCL for TTHM or HAA5 anywhere in its distribution system.

b. The altered practices may include line flushing and replacement, changes to points of disinfection, elimination of points of disinfection, tank turnover practices, or other changes to facilitate reductions in levels of contamination, and shall be approved by the cabinet in accordance with conditions listed in 40 C.F.R. 1412.130(b), January 16, 2001, before the altered practices begin.

2.a. A purchasing system shall cooperate in the development of a monitoring plan required from the producing system under paragraph (b) of this subsection.

b. A purchasing system shall monitor for maximum residual disinfectant levels at the same points in the distribution system, and at the same time as total coliforms are sampled as specified in 401 KAR 8:200.

Section 3. Maximum Levels. (1) Maximum contaminant level. The maximum contaminant level or MCL for disinfection by-products shall be:

(a) Total trihalomethanes, or TTHMs: 0.080 mg/L;

(b) Haloacetic acids five, or HAA5: 0.060 mg/L;

(d) Chlorite: one and zero-tenths (1.0) mg/L.

(2) Maximum residual disinfectant level.

(a) The maximum residual disinfectant level, or MRDL, shall be:

1. Chlorine: four and zero-tenths (4.0) mg/L as Cl₂;

2. Chloramines: four and zero-tenths (4.0) mg/L as Cl₂; and

3. Chlorine dioxide: zero and eight-tenths (0.8) mg/L as ClO₂.

(b)1. For chlorine and chloramines, a public water system shall be in compliance with the MRDL if the running annual average of monthly averages of samples taken in the distribution system computed quarterly is less than or equal to the MRDL.

2. For chlorine dioxide, a public water system shall be in compliance with the MRDL if daily samples are taken at the entrance to the distribution system, and two (2) consecutive daily samples shall not exceed the MRDL.

Section 4. Best Available Technology. (1) Disinfection by-products listed. The following shall be the best technology, treatment techniques, or other means available for achieving compliance with the MCLs for disinfection by-products in Section 3 of this administrative regulation:

(a) TTHM: Enhanced coagulation or enhanced softening or GAC10, with chlorine as the primary and residual disinfectant;

(b) HAA5: Enhanced coagulation or enhanced softening or GAC10, with chlorine as the primary and residual disinfectant;

(d) Chlorite: Control of treatment processes to reduce disinfectant demand and control of disinfection treatment processes to reduce disinfectant levels.

(2) Disinfectant residuals. The best technology, treatment techniques, or other means available for achieving compliance with the MRDL listed in Section 3 of this administrative regulation shall be:

(a) Control of treatment processes to reduce disinfectant demand; and

(b) Control of disinfection treatment processes to reduce disinfectant levels.

Section 5. Analytical Requirements. (1) Except as provided in this section, a system shall sample and analyze according to the procedures in 40 C.F.R. 141.131, January 16, 2001)].

(2) A system shall have the samples analyzed by a laboratory that has been certified by the U.S. EPA or the cabinet, pursuant to 40 C.F.R. 141.131(b)(3), June 29, 2006, according to 401 KAR 8:040.

(3) A party approved by the U.S. Environmental Protection Agency or the cabinet shall measure daily chlorite samples at the entrance to the distribution system.

(4) A public water system may measure residual disinfectant concentrations for chlorine, chloramines, and chlorine dioxide by using a N,N, -diethyl-p-phenylenediamine (DPD) colorimetric test kit.

(5) Residual disinfectant concentrations, alkalinity, and total organic carbon; or TOC, specific ultraviolet absorbance (including dissolved organic carbon and UV-254) and pH shall be measured by an operator certified pursuant to 401 KAR 8:030, or a person under the direct supervision of a certified operator, or a certified laboratory pursuant to 401 KAR 8:040.

Section 6. Monitoring Requirements. (1) General requirements.

(a) A system shall take all samples during normal operating conditions.

(b) A system may consider multiple wells drawing water from a single aquifer as one (1) treatment plant for determining the minimum number of TTHM and HAA5 samples required, as approved pursuant to 40 C.F.R. 142.16(h)(5), April 17, 1989.

(c) Failure to monitor in accordance with the monitoring plan required in subsection (6) of this section shall be a monitoring violation.

(d) Failure to monitor shall be a violation for the entire period covered by the annual average, if 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 an MCL or MRDL.

(2) Monitoring requirements for disinfection by-products.

(a) TTHMs and HAA5.

1. Routine monitoring. A system shall monitor at the frequency and locations indicated in the following table:

3.a. A system on a reduced monitoring schedule may remain on that reduced schedule if the average of all samples taken in the year, for systems that shall monitor quarterly, or the result of the sample, for systems that shall not monitor more frequently than annually, is not more than 0.060 mg/L and 0.045 mg/L for TTHMs and HAA5, respectively.

b. A system that does not meet these levels shall resume monitoring at the frequency identified in the sample location column in subparagraph 1 of this paragraph in the quarter immediately following the quarter in which the system exceeds 0.060 mg/L for TTHM and 0.045 mg/L for HAA5.

c. For a system that uses only groundwater not under the direct influence of surface water and that serves fewer than 10,000 persons, if either the TTHM annual average is >0.080 mg/L or the HAA5 annual average is >0.060 mg/L, the system shall go to increased monitoring identified in the sample location column in subparagraph 1 of this paragraph in the quarter immediately following the quarter in which the system exceeds 0.080 mg/L for TTHMs or 0.060 mg/L for HAA5s.

4. A system on increased monitoring, may return to routine monitoring if the TTHM annual average is £ 0.040 mg/L and HAA5 annual average is £ 0.030 mg/L.

5. The criteria for returning a system to routine monitoring shall be as established in 40 C.F.R. 141.132(b)(1)(vi), January 4, 2006.

(b) Chlorite. A community or nontransient noncommunity water system using chlorine dioxide for disinfection or oxidation shall conduct monitoring for chlorite.

1. Routine monitoring.

a. Daily monitoring. A system shall take daily samples at the entrance to the distribution system. For a daily sample that exceeds the chlorite MCL, the system shall take additional samples in the distribution system the following day at the locations required by subparagraph 2 of this paragraph, in addition to the sample required at the entrance to the distribution system.

b. Monthly monitoring. A system shall take a three (3) sample set each month in the distribution system. Additional routine sampling shall be conducted in the same manner as three (3) sample sets, at the specified locations. The system may use the results of additional monitoring conducted under subparagraph 2 of this paragraph to meet the requirement for monitoring in this clause. The system shall take one (1) sample at each of the following locations:

(i) Near the first customer;

(ii) At a location representative of average residence time; and

(iii) At a location reflecting maximum residence time in the distribution system.

2. Additional monitoring. On each day following a routine sample monitoring result that exceeds the chlorite MCL at the entrance to the distribution system, the system shall take three (3) chlorite distribution samples at the following locations:

a. As close to the first customer as possible;

b. In a location representative of average residence time; and

c. As close to the end of the distribution system as possible to reflect maximum residence time in the distribution system.

3. Reduced monitoring.

a. Chlorite monitoring at the entrance to the distribution system required by subparagraph 1a of this paragraph shall not be reduced.

b.(i) Chlorite monitoring in the distribution system required by subparagraph 1b of this paragraph may be reduced to one (1) three (3) sample set per quarter after one (1) year of monitoring if no individual chlorite sample taken in the distribution system under subparagraph 1b of this paragraph has exceeded the chlorite MCL and the system has not been required to conduct monitoring under subparagraph 2 of this paragraph.

(ii) The system may remain on the reduced monitoring schedule until either any of the three (3) individual chlorite samples taken quarterly in the distribution system under subparagraph 1b of this paragraph exceed the chlorite MCL or the system shall be required to conduct monitoring under subparagraph 2 of this paragraph. The system shall then revert to routine monitoring.

1.a. Routine monitoring. A community or nontransient noncommunity water system using ozone for disinfection or oxidation shall take one (1) sample per month for each treatment plant in the system that uses ozone.

b. A system shall take the sample monthly at the entrance to the distribution system while the ozonation system is operating under normal conditions.

2. Reduced monitoring.

a. A system required to analyze for bromate may reduce monitoring from monthly to once per quarter, if the system demonstrates that the average source water bromide concentration is less than 0.05 mg/L, based upon representative monthly bromide measurements for one (1) year.

b. The system may remain on reduced bromate monitoring until the running annual average source water bromide concentration, computed quarterly, is equal to or greater than 0.05 mg/L, based upon representative monthly measurements.

c. If the running annual average source water bromide concentration is greater than or equal to 0.05 mg/L, the system shall resume routine monitoring required by subparagraph 1 of this paragraph.

(3) Monitoring requirements for disinfectant residuals.

(a) Chlorine and chloramines.

1. Routine monitoring. A community or nontransient noncommunity water system that uses chlorine or chloramines shall measure the residual disinfectant level in the distribution system at the same time as total coliforms are sampled, as specified in 401 KAR 8:200.

2. Reduced monitoring. Monitoring shall not be reduced.

(b) Chlorine dioxide.

1.a. Routine monitoring. A community, nontransient noncommunity, or transient noncommunity water system that uses chlorine dioxide for disinfection or oxidation shall take daily samples at the entrance to the distribution system.

b. For a daily sample that exceeds the MRDL, the system shall take samples in the distribution system the following day at the locations required by subparagraph 2 of this paragraph, in addition to the sample required at the entrance to the distribution system.

2. Additional monitoring.

a. Each day following a routine sample monitoring result that exceeds the MRDL, the system shall take three (3) chlorine dioxide distribution system samples.

b. If chlorine dioxide or chloramines shall be used to maintain a disinfectant residual in the distribution system, or if chlorine is used to maintain a disinfectant residual in the distribution system and there are not disinfection addition points after the entrance to the distribution system, i.e., no booster chlorination, the system shall take three (3) samples as close to the first customer as possible, at an interval of at least six (6) hours.

c. If chlorine is used to maintain a disinfectant residual in the distribution system and there are one (1) or more disinfection addition points after the entrance to the distribution system, i.e., booster chlorination, the system shall take one (1) sample at each of the following locations:

(i) As close to the first customer as possible;

(ii) In a location representative of average residence time; and

(iii) As close to the end of the distribution system as possible, reflecting maximum residence time in the distribution system.

3. Reduced monitoring. Chlorine dioxide monitoring shall not be reduced.

(4) Monitoring requirements for disinfection by-product precursors.

(a) Routine monitoring.

1. A system that uses as its source surface water or groundwater under the direct influence of surface water that uses conventional filtration treatment shall monitor each treatment plant for total organic carbons, or TOC, not later than the point of combined filter effluent turbidity monitoring and representative of the treated water.

2. A system required to monitor under this paragraph shall also monitor for TOC in the source water before any treatment at the same time as monitoring for TOC in the treated water.

3. These samples of the source water and treated water shall be considered paired samples.

4. When the source water sample is taken, a system shall monitor for alkalinity in the source water before any treatment.

5. A system shall take one (1) paired sample and one (1) source water alkalinity sample per month per plant at a time representative of normal operating conditions and influent water quality.

(b) Reduced monitoring.

1. A system that uses as its source surface water or groundwater under the direct influence of surface water with an average treated water TOC of less than two and zero-tenths (2.0) mg/L for two (2) consecutive years, or less than one and zero-tenths (1.0) mg/L for one (1) year, may reduce monitoring for both TOC and alkalinity to one (1) paired sample and one (1) source water alkalinity sample per plant per quarter.

2. The system shall revert to routine monitoring in the month following the quarter if the annual average treated water TOC is greater than or equal to two and zero-tenths (2.0) mg/L.

(5) Bromide.

(a) A system required to analyze for bromate may reduce bromate monitoring from monthly to once per quarter, if the system demonstrates that the average source water bromide concentration is less than 0.05 mg/L, based upon representative monthly measurements for one (1) year.

(b) The system shall continue bromide monitoring to remain on reduced bromate monitoring.

(6) Monitoring plan.

(a) A system required to monitor under this administrative regulation shall develop and implement a monitoring plan.

(b) The system shall maintain the plan and make it available for inspection by the cabinet and the general public not later than thirty (30) days following the applicable compliance dates in Section 2 of this administrative regulation.

(c) A system that uses as its source surface water or groundwater under the direct influence of surface water serving more than 3,300 people shall submit a copy of the monitoring plan to the cabinet not later than the date of the first report required by Section 8 of this administrative regulation.

(d) After review, in accordance with conditions established in 40 C.F.R. 141.132(f), January 4, 2006, the cabinet may require changes specified in 40 C.F.R. 141.132(f), January 4, 2006, in a plan element.

(e) The monitoring plan shall include at least the following elements:

1. Specific location and schedule for collecting samples for a parameter included in this administrative regulation;

2. How the system will calculate compliance with MCLs, MRDLs, and treatment techniques; and

3. If providing water to a consecutive system, the sampling plan for TTHMs and HAA5s shall reflect the entire distribution system.

Section 7. Compliance Requirements. (1) General requirements.

(a)1. If compliance is based on a running annual average of monthly or quarterly samples or averages and the system fails to monitor for TTHM, HAA5, or bromate, this failure to monitor shall be a monitoring violation for the entire period covered by the annual average.

2. If 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 MRDLs for chlorine and chloramines, this failure to monitor shall be a monitoring violation for the entire period covered by the annual average.

(b) A sample taken and analyzed under the provisions of this administrative regulation shall be included in determining compliance, even if the number of samples taken is greater than the minimum required.

(c) If during the first year of monitoring under Section 6 of this administrative regulation, an individual quarter's average causes or shall cause the running annual average of that system to exceed the MCL, the system shall be out of compliance at the end of that quarter.

(2) Disinfection by-products.

(a) TTHMs and HAA5.

1. For a system that monitors quarterly, compliance with MCLs in Section 3 of this administrative regulation shall be based on a running annual arithmetic average, computed quarterly, of quarterly arithmetic averages of the samples collected by the system as prescribed by Section 6(2)(a) of this administrative regulation.

2.a. For a system monitoring less frequently than quarterly, a system shall demonstrate MCL compliance if the average of samples taken that year under the provisions of Section 6(2)(a) of this administrative regulation does not exceed the MCLs listed in Section 3 of this administrative regulation.

b. If the average of the samples exceeds the MCL, the system shall increase monitoring to once per quarter per treatment plant, and the system shall not be in violation of the MCL until it has completed one (1) year of quarterly monitoring, unless the result of fewer than four (4) quarters of monitoring will cause the running annual average to exceed the MCL, in which case the system shall be in violation at the end of that quarter.

c. A system required to increase monitoring frequency to quarterly monitoring shall calculate compliance by including the sample that triggered the increased monitoring, plus the following three (3) quarters of monitoring.

3. If the running annual arithmetic average of quarterly averages covering a consecutive four (4) quarter period exceeds the MCL, the system shall be in violation of the MCL and shall notify the public pursuant to 401 KAR 8:070, in addition to reporting to the cabinet pursuant to Section 8 of this administrative regulation.

4. If a public water system fails to complete four (4) consecutive quarters of monitoring, compliance with the MCL for the last four (4) quarter compliance period shall be based on an average of the available data.

(b) Bromate.

1. Compliance shall be based on a running annual arithmetic average, computed quarterly, of monthly samples, or for months in which the system takes more than one (1) sample, the average of the samples taken during the month, collected by the system as prescribed by Section 6(2)(c) of this administrative regulation.

2. If the average of samples covering a consecutive four (4) quarter period exceeds the MCL, the system shall be in violation of the MCL and shall notify the public pursuant to 401 KAR 8:070, in addition to reporting to the cabinet pursuant to Section 8 of this administrative regulation.

3. If a public water system fails to complete twelve (12) consecutive months' monitoring, compliance with the MCL for the last four (4) quarter compliance period shall be based on an average of the available data.

1. Compliance shall be based on an arithmetic average of each three (3) sample set taken in the distribution system as prescribed by Section 6(2)(b)1b and 2 of this administrative regulation.

2. If the arithmetic average of a three (3) sample set exceeds the MCL, the system shall be in violation of the MCL and shall notify the public pursuant to 401 KAR 8:070, in addition to reporting to the cabinet pursuant to Section 8 of this administrative regulation.

(3) Disinfectant residuals.

(a) Chlorine and chloramines.

1.a. Compliance shall be based on a running annual arithmetic average, computed quarterly, of monthly averages of all samples collected by the system under Section 6(3)(a) of this administrative regulation.

b. If the average covering a consecutive four (4) quarter period exceeds the MRDL, the system shall be in violation of the MRDL and shall notify the public pursuant to 401 KAR 8:070, in addition to reporting to the cabinet pursuant to Section 8 of this administrative regulation.

2.a. If a system switched between the use of chlorine and chloramines for residual disinfection during the year, compliance shall be determined by including all monitoring results of both chlorine and chloramines in calculating compliance.

b. A report submitted pursuant to Section 8 of this administrative regulation shall clearly indicate which residual disinfectant was analyzed for each sample.

(b) Chlorine dioxide.

1. Acute violations.

a. Compliance shall be based on consecutive daily samples collected by the system under Section 6(3)(b) of this administrative regulation.

b. If a daily sample taken at the entrance to the distribution system exceeds the MRDL, and on the following day one (1) or more of the three (3) samples taken in the distribution system exceeds the MRDL, the system shall be in violation of the MRDL.

c. The system shall take immediate corrective action to lower the level of chlorine dioxide below the MRDL and shall notify the public pursuant to the procedures for acute health risks in 401 KAR 8:070, Section 2, in addition to reporting to the cabinet pursuant to Section 8 of this administrative regulation.

d. Failure to take samples in the distribution system the day following an exceedance of the chlorine dioxide MRDL at the entrance to the distribution system shall also be an MRDL violation.

e. The system shall notify the public of the violations in accordance with the provisions for acute violations under 401 KAR 8:070, Section 2, in addition to reporting to the cabinet pursuant to Section 8 of this administrative regulation.

2. Nonacute violations.

a. Compliance shall be based on consecutive daily samples collected by the system under Section 6(3)(b) of this administrative regulation.

b. If two (2) consecutive daily samples taken at the entrance to the distribution system exceed the MRDL and all distribution system samples taken are below the MRDL, the system shall be in violation of the MRDL and the system shall take corrective action to lower the level of chlorine dioxide below the MRDL at the point of sampling and shall notify the public pursuant to the procedures for nonacute health risks in 401 KAR 8:070, Section 3, in addition to reporting to the cabinet pursuant to Section 8 of this administrative regulation.

c. Failure to monitor at the entrance to the distribution system the day following an exceedance of the chlorine dioxide MRDL at the entrance to the distribution system also shall be an MRDL violation, and the system shall notify the public of the violation in accordance with the provisions for nonacute violations in 401 KAR 8:070, Section 3, in addition to reporting to the cabinet pursuant to Section 8 of this administrative regulation.

(4) Disinfection by-product precursors.

(a) Compliance shall be determined as specified by Section 9(3) of this administrative regulation.

(b) A system may begin monitoring to determine if Step 1 TOC removals shall be able to be met twelve (12) months before the compliance date for the system. This monitoring shall not be required, and failure to monitor during this period shall not be a violation. A system that does not monitor during this period and then determines in the first twelve (12) months that shall not be able to meet the Step 1 requirements in Section 9(2)(b) of this administrative regulation and shall apply for alternate minimum TOC removal or Step 2, requirements, shall not be eligible for retroactive approval of Step 2 requirements, as allowed pursuant to Section 9(2)(c) of this administrative regulation, and shall be in violation.

(d) For a system required to meet Step 1 TOC removals, if the value calculated under Section 9(3)(a)4 of this administrative regulation is less than 1.00, the system shall be in violation of the treatment technique requirements and shall notify the public pursuant to 401 KAR 8:070, in addition to reporting to the cabinet pursuant to Section 8 of this administrative regulation.

Section 8. Reporting and Recordkeeping Requirements. This section prescribes the reporting and record keeping requirements.

(1)(a) A system required to sample quarterly or more frequently shall report to the cabinet within ten (10) days after the end of each quarter in which samples were collected, notwithstanding the provisions of 401 KAR 8:020.

(b) A system required to sample less frequently than quarterly shall report to the cabinet within ten (10) days after the end of each monitoring period in which samples were collected.

(2) Disinfection by-products.

(a) A system monitoring for TTHM and HAA5 under the requirements of Section 6(2) of this administrative regulation on a quarterly or more frequent basis shall report:

1. The number of samples taken during the last quarter;

2. The location, date, and result of each sample taken during the last quarter;

3. The arithmetic average of all samples taken in the last quarter;

4. The annual arithmetic average of the quarterly arithmetic average of this section for the last four (4) quarters; and

5. If the MCL was violated or not, based on Section 7(2)(a) of this administrative regulation.

(b) A system monitoring for TTHMs and HAA5 under the requirements of Section 6(2) of this administrative regulation less frequently than quarterly, but at least annually, shall report:

1. The number of samples taken during the last year;

2. The location, date, and result of each sample taken during the last quarter;

3. The arithmetic average of all samples taken over the last year; and

4. If the MCL was violated or not, based on Section 7(2)(a) of this administrative regulation.

(c) A system monitoring for TTHMs and HAA5 under the requirements of Section 6(2) of this administrative regulation less frequently than annually shall report:

1. The location, date, and result of the last sample taken; and

2. If the MCL was violated or not, based on Section 7(2)(a) of this administrative regulation.

(d) A system monitoring for chlorite under the requirements of Section 6(2) of this administrative regulation shall report:

1. The number of samples taken each month for the last three (3) months;

2. The location, date, and result of each sample taken during the last quarter;

3. For each month in the reporting period, the arithmetic average of all samples taken in the month; and

4. If the MCL was violated or not, based on Section 7(2)(c) of this administrative regulation, in which month it was violated, and how many times it was violated each month.

(e) A system monitoring for bromate under the requirements of Section 6(2) of this administrative regulation shall report:

1. The number of samples taken during the last quarter;

2. The location, date, and result of each sample taken during the last quarter;

3. The arithmetic average of the monthly arithmetic averages of all samples taken in the last year; and

4. If the MCL was exceeded or not, based on Section 7(2)(b) of this administrative regulation.

(3) Disinfectants.

(a) A system monitoring for chlorine or chloramines under the requirements of Section 6(3) of this administrative regulation shall report:

1. The number of samples taken during each month of the last quarter;

2. The monthly arithmetic average of all samples taken in each month for the last twelve (12) months;

3. The arithmetic average of all monthly averages for the last twelve (12) months; and

4. If the MRDL was exceeded or not, based on Section 7(3)(a) of this administrative regulation.

(b) A system monitoring for chlorine dioxide under the requirements of Section 6(3) of this administrative regulation shall report:

1. The dates, results, and locations of samples taken during the last quarter;

2. If the MRDL was exceeded or not, based on Section 7(3)(b) of this administrative regulation; and

3. If the MRDL was exceeded or not in any two (2) consecutive daily samples and if the resulting violation was acute or nonacute.

(4) Disinfection by-product precursors and enhanced coagulation or enhanced softening.

(a) A system monitoring monthly or quarterly for TOC under the requirements of Section 6(4) of this administrative regulation and that shall meet the enhanced coagulation or enhanced softening requirements in Section 9(2)(b) or (c) of this administrative regulation shall report:

1. The number of paired samples taken during the last quarter;

2. The location, date, and result of each paired sample and associated alkalinity taken during the last quarter;

3. For each month in the reporting period that paired samples were taken, the arithmetic average of the percent reduction of TOC for each paired sample and the required TOC percent removal;

4. Calculations for determining compliance with the TOC percent removal requirements, as provided in Section 9(3)(a) of this administrative regulation; and

5. If the system is in compliance with the enhanced coagulation or enhanced softening percent removal requirements in Section 9(2) of this administrative regulation for the last four (4) quarters.

(b) A system monitoring monthly or quarterly for TOC under the requirements of Section 6(4) of this administrative regulation and meeting one (1) or more of the alternative compliance criteria in Section 9(1)(b) or (c) of this administrative regulation shall report:

1. The alternative compliance criterion that the system is using;

2. The number of paired samples taken during the last quarter;

3. The location, date, and result of each paired sample and associated alkalinity taken during the last quarter;

4. The running annual arithmetic average based on monthly averages, or quarterly samples, of source water TOC for a system meeting a criterion in Section 9(1)(b)1 or 3 of this administrative regulation or of treated water TOC for a system meeting the criterion in Section 9(1)(b)2 of this administrative regulation;

5. The running annual arithmetic average based on monthly average, or quarterly samples, of source water specific ultraviolet absorbance, or SUVA, for a system meeting the criterion in Section 9(1)(b)5 of this administrative regulation or of treated water SUVA for a system meeting the criterion in Section 9(1)(b)6 of this administrative regulation;

6. The running annual average of source water alkalinity for a system meeting the criterion in Section 9(1)(b)3 of this administrative regulation and of treated water alkalinity for a system meeting the criterion in Section 9(1)(c)1 of this administrative regulation;

7. The running annual average for both TTHM and HAA5 for a system meeting the criterion in Section 9(1)(b)3 or 4 of this administrative regulation;

8. The running annual average of the amount of magnesium hardness removal, as CACO₃ in mg/L, for a system meeting the criterion in Section 9(1)(c)2 of this administrative regulation; and

9. If the system is in compliance or not with the particular alternative compliance criterion in Section 9(1)(b) or (c) of this administrative regulation.

Section 9. Treatment Technique for Control of Disinfection By-product Precursors. (1) Applicability.

(a) A system that uses as its source surface water or groundwater under the direct influence of surface water that uses conventional filtration treatment shall operate with enhanced coagulation or enhanced softening to achieve the TOC percent removal level specified in subsection (2) of this section unless the system meets at least one (1) of the alternative compliance criteria listed in paragraph (b) or (c) of this subsection.

(b) Alternative compliance criteria for enhanced coagulation and enhanced softening system. A system that uses as its source surface water or groundwater under the direct influence of surface water using conventional filtration treatment may use the alternative compliance criteria in subparagraphs 1 to 6 of this paragraph to comply with this section, instead of complying with subsection (2) of this section. A system shall still comply with the monitoring requirements in Section 6(4) of this administrative regulation.

1. The system's source water TOC level, measured according to 40 C.F.R. 141.131(d)(3), January 16, 2001, is less than two and zero-tenths (2.0) mg/L, calculated quarterly as a running annual average;

2. The system's treated water TOC level, measured according to 40 C.F.R. 141.131(d)(3), January 16, 2001, is less than two and zero-tenths (2.0) mg/L, calculated quarterly as a running annual average;

3.a. The system's source water TOC level, measured according to 40 C.F.R. 141.131(d)(3), January 16, 2001, is less than four and zero-tenths (4.0) mg/L, calculated quarterly as a running annual average;

b. The source water alkalinity, measured according to 40 C.F.R. 141.131(d)(1), January 16, 2001, shall be greater than sixty (60) mg/L as CaCO₃, calculated quarterly as a running annual average; and

c. The TTHM and HAA5 running annual averages shall not be greater than 0.040 mg/L and 0.030 mg/L, respectively;

4. The TTHM and HAA5 running annual averages shall not be greater than 0.040 mg/L and 0.030 mg/L, respectively, and the system uses only chlorine for primary disinfection and maintenance of a residual in the distribution system;

5. The system's source water SUVA, before any treatment and measured monthly according to 40 C.F.R. 141.131(d)(4), January 16, 2001, shall be less than or equal to two and zero-tenths (2.0) L/mg-m, calculated quarterly as a running annual average;

6. The system's finished water SUVA, measured monthly according to 40 C.F.R. 141.131(d)(4), January 16, 2001, shall be less than or equal to two and zero-tenths (2.0) L/mg-m, calculated quarterly as a running annual average.

(c) Additional alternative compliance criteria for a softening system. A system practicing enhanced softening that is not able to achieve the TOC removals required by subsection (2)(b) of this section may use the alternative compliance criteria in subparagraphs 1 and 2 of this paragraph instead of complying with subsection (2) of this section. The system shall still comply with monitoring requirements in Section 6(4) of this administrative regulation.

1. Softening that results in lowering the treated water alkalinity to less than sixty (60) mg/L as CaCO₃, measured monthly according to 40 C.F.R. 141.131(d)(1), January 16, 2001, and calculated quarterly as a running annual average; and

2. Softening that results in removing at least ten (10) mg/L of magnesium hardness as CaCO₃, measured monthly and calculated quarterly as an annual running average.

(2) Enhanced coagulation and enhanced softening performance requirements.

(a) A system shall achieve the percent reduction of TOC specified in paragraph (b) of this subsection between the source water and the combined filter effluent, unless the cabinet approves a system's request for Step 2 requirements under paragraph (c) of this subsection.

(b)1. Required Step 1 TOC reductions, indicated in the following table, are based upon specified source water parameters measured in accordance with 40 C.F.R. 141.131(d), January 16, 2001.

2. A system practicing softening shall meet the Step 1 TOC reductions in the column of the table for source water alkalinity greater than 120 mg/L, for the specified source water TOC:

Step 1 Required Removal Percent of TOC by Enhanced Coagulation and Enhanced Softening for a System that Uses as its Source Surface Water or Groundwater Under the Direct Influence of Surface Water Using Conventional Treatment^1,2
Source water TOC, mg/L	Source water alkalinity, mg/L as CaCO₃
Source water TOC, mg/L	0 - 60	61 - 120	> 120³
2.0 £ TOC £ 4.0	35.0 %	25.0 %	15.0 %
4.0 < TOC £ 8.0	45.0 %	35.0 %	25.0 %
TOC >8.0	50.0 %	40.0 %	30.0 %
¹A system meeting a condition in subsection (1)(b) of this section need not operate with enhanced coagulation. ²A softening system meeting an alternative compliance criterion in subsection (3) of this section need not operate with enhanced softening. ³A system practicing softening shall meet the TOC removal requirements in this column.

(c)1. A system that uses as its source surface water or groundwater under the direct influence of surface water and that uses conventional treatment that is not able to achieve the Step 1 TOC removals required by paragraph (b) of this subsection due to water quality parameters or operational constraints shall apply to the cabinet, within three (3) months of failure to achieve the TOC removals required by paragraph (b) of this subsection, for approval of Step 2 removal requirements submitted by the system.

2. The cabinet may determine pursuant to 40 C.F.R. 141.135(b)(3), January 4, 2006, that Step 2 requirements shall be retroactive for the purpose of determining compliance.

3. Until the cabinet approves the Step 2 requirements, in accordance with the timeframe described in 40 C.F.R. 141.135(b)(3), January 4, 2006, the system shall meet the Step 1 TOC removals contained in paragraph (b) of this subsection.

(d) Step 2 requirements.

1. An application to the cabinet by an enhanced coagulation system for approval of Step 2 requirements under paragraph (c) of this subsection shall include, as a minimum, the results of bench- or pilot-scale testing conducted under subparagraph 2a of this paragraph.

2. The submitted bench- or pilot-scale testing shall be used to determine the alternate enhanced coagulation level.

a.(i) Alternate enhanced coagulation level shall be the coagulation at a coagulant dose and pH as determined by the method described in this subparagraph and clauses b through e of this subparagraph so that an incremental addition of ten (10) mg/L of alum, or equivalent amount of ferric salt, results in a TOC removal of less than or equal to three-tenths (0.3) mg/L.

(ii) The percent removal of TOC at this point of the "TOC removal versus coagulant dose" curve then shall be the minimum TOC removal required for the system.

(iii) Upon approval by the cabinet, in accordance with approval criteria established in 40 C.F.R. 141.135(b)(4)(i), January 4, 2006, this minimum requirement shall supersede the minimum TOC removal required by the table in paragraph (b) of this subsection.

(iv) This requirement shall be effective until the cabinet approves a new value based on the results of a new bench- and pilot-scale test.

(v) Failure to achieve the alternative minimum TOC removal levels set by the cabinet shall be a violation of this administrative regulation.

b. Bench- or pilot-scale testing of enhanced coagulation shall be conducted by using representative water samples and adding ten (10) mg/L increments of alum, or equivalent amounts of ferric salt, until the pH is reduced to a level less than or equal to the enhanced coagulation Step 2 target pH shown in the following table:

Enhanced Coagulation Step 2 Target pH
Alkalinity, mg/L measured as CaCO₃	Target pH
0 - 60	5.5
61 - 120	6.3
121 - 240	7.0
> 240	7.5

c. For waters with alkalinities of less than sixty (60) mg/L for which addition of small amounts of alum or equivalent addition of iron coagulant drives the pH below five and five-tenths (5.5) before significant TOC removal occurs, the system shall add necessary chemicals to maintain the pH between five and three-tenths (5.3) and five and seven-tenths (5.7) in samples until the TOC removal of three-tenths (0.3) mg/L per ten (10) mg/L alum added, or equivalent addition of iron coagulant, is reached.

d. The system may operate at a coagulant dose or pH necessary, consistent with other administrative regulations in 401 KAR 8:010 to 401 KAR 8:700, to achieve the minimum TOC percent removal approved under paragraph (c) of this subsection.

e. If the TOC removal is consistently less than three-tenths (0.3) mg/L of TOC per ten (10) mg/L of incremental alum dose, at all doses of alum, or equivalent addition of iron coagulant, the water is deemed to contain TOC not amenable to enhanced coagulation. The system may then apply to the cabinet for a waiver of enhanced coagulation requirements.

(3) Compliance calculations.

(a)1. A system that uses as its source surface water or groundwater under the direct influence of surface water other than that identified in subsection (1)(b) or (c) of this section, shall comply with requirements in subsection (2)(b) or (c) of this section.

2. A system shall calculate compliance quarterly, beginning after the system has collected twelve (12) months of data, by determining an annual average using the following method:

a. Determine actual monthly TOC percent removal, which shall be calculated as:

(1 - (treated water TOC/source water TOC)) x 100;

b. Determine the required monthly TOC percent removal from either the table in subsection (2)(b) of this section or from subsection (2)(c) of this section;

c. Divide the value in subparagraph 1 of this paragraph by the value in subparagraph 2 of this paragraph;

d. Add together the results of subparagraph 3 of this paragraph for the past twelve (12) months and divide by twelve (12); and

e. If the value calculated in subparagraph 4 of this paragraph is less than 1.00, the system shall not be in compliance with the TOC percent removal requirements.

(b) A system may use the provisions in subparagraph 1 to 5 of this paragraph instead of the calculations in paragraph (a)1a through e of this subsection to determine compliance with TOC percent removal requirements:

1. In a month that the system's treated or source water TOC levels, measured according to 40 C.F.R. 141.131(d)(3), January 16, 2001, is less than two and zero-tenths (2.0) mg/L, the system may assign a monthly value of one and zero-tenths (1.0), instead of the value calculated in paragraph (a)1c of this subsection, when calculating compliance under the provisions of paragraph (a) of this subsection;

2. In a month that a system practicing softening removes at least ten (10) mg/L of magnesium hardness, as CaCO₃, the system may assign a monthly value of one and zero-tenths (1.0), instead of the value calculated in paragraph (a)3 of this subsection, when calculating compliance under the provisions of paragraph (a) of this subsection;

3. In a month that the system's source water SUVA, before treatment and measured according to 40 C.F.R. 141.131(d)(4), January 16, 2001, is less than or equal to two and zero-tenths (2.0) L/mg-m, the system may assign a monthly value of one and zero-tenths (1.0) instead of the value calculated in paragraph (a)1c of this subsection, when calculating compliance under the provisions of paragraph (a) of this subsection;

4. In a month that the system's finished water SUVA, measured according to 40 C.F.R. 141.131(d)(4), January 16, 2001, is less than or equal to two and zero-tenths (2.0) L/mg-m, the system may assign a monthly value of one and zero-tenths (1.0) instead of the value calculated in paragraph (a)1c of this subsection when calculating compliance under the provisions of paragraph (a) of this subsection; and

5. In a month that the system enhanced softening lowers alkalinity below sixty (60) mg/L as CaCO₃, the system may assign a monthly value of one and zero-tenths (1.0) instead of the value calculated in paragraph (a)1c of this subsection when calculating compliance under the provisions of paragraph (a) of this subsection.

(c) A system that uses as its source surface water or groundwater under the direct influence of surface water and that uses conventional treatment may also comply with the requirements of this section by meeting the criteria in subsection (1)(b) or (c) of this section.

(4) Treatment technique requirements for disinfection by-products (DBP) precursors. For a system that uses surface water or groundwater as its source and that uses conventional treatment, enhanced coagulation or enhanced softening shall be a treatment technique to control the level of disinfection by-product precursors in a drinking water treatment or drinking water distribution system. (27 Ky.R. 1680; Am. 2529; 2764; eff. 4-9-2001; 1677; 3009; 3640; eff. 6-13-2007.)

Routine Monitoring Frequency for TTHMs and HAA5
System Type	Minimum monitoring frequency	Sample location in the distribution system
A system that uses as its source surface water or groundwater under the direct influence of surface water and that serves at least 10,000 persons.	Four (4) water samples per quarter per treatment plant.	At least twenty-five (25) percent of all samples collected each quarter at locations representing maximum residence time. Remaining samples shall be taken at locations representative of at least average residence time in the distribution system and representing the entire distribution system, taking into account the number of persons served, different sources of water, and different treatment methods.¹
A system that uses as its source surface water or groundwater under the direct influence of surface water and that serves from 500 to 9,999 persons.	One (1) water sample per quarter per treatment plant.	Locations representing maximum residence time.¹
A system that uses as its source surface water or groundwater under the direct influence of surface water and that serves fewer than 500 persons.	One (1) sample per year per treatment plant during month of warmest water temperature.	Locations representing maximum residence time.¹ If the sample, or average of annual samples if more than one (1) sample is taken, exceeds the MCL, system shall increase monitoring to one (1) sample per treatment plant per quarter, taken at a point reflecting the maximum residence time in the distribution system, until system meets reduced monitoring criteria in subparagraph 4 of this paragraph.
System using only groundwater not under direct influence of surface water, using chemical disinfectant, and serving at least 10,000 persons.	One (1) water sample per quarter per treatment plant².	Location representing maximum residence time.¹
System using only groundwater not under direct influence of surface water, using chemical disinfectant, and serving fewer than 10,000 persons.	One (1) sample per year per treatment plant² during month of warmest water temperature.	Locations representing maximum residence time.¹ If the sample, or average of annual samples, if more than one (1) sample is taken, exceeds the MCL, system shall increase monitoring to one (1) sample per treatment plant per quarter, taken at a point reflecting the maximum residence time in the distribution system, until the system meets criteria in subparagraph 4 of this paragraph for reduced monitoring.
¹If a system elects to sample more frequently than the minimum required, at least twenty-five (25) percent of all samples collected each quarter, including those taken in excess of the required frequency, shall be taken at locations that represent the maximum residence time in the distribution system. The remaining samples shall be taken at locations representative of at least average residence time in the distribution system. ²Multiple wells drawing water from a single aquifer may be considered one (1) treatment plant for determining the minimum number of samples required.

Reduced Monitoring Frequency for TTHM and HAA5
If the system type is:	And the system has monitored at least one (1) year and the	Then the system may reduce monitoring to this level:
System that uses as its source surface water or groundwater under the direct influence of surface water, that serves at least 10,000 persons, and that has a source water annual average TOC level, before treatment, of £4.0 mg/L.	TTHM annual average £0.040 mg/L and HAA5 annual average £0.030 mg/L.	One (1) sample per treatment plant per quarter at distribution system location reflecting maximum residence time.
System that uses as its source surface water or groundwater under the direct influence of surface water that serves from 500 to 9,999 persons, and that has a source water annual average TOC level, before treatment, of £4.0 mg/L.	TTHM annual average £0.040 mg/L and HAA5 annual average £0.030 mg/L.	One (1) sample per treatment plant per year at distribution system location reflecting maximum residence time during month of warmest water temperature. A system that uses as its source surface water or groundwater under the direct influence of surface water that serves fewer than 500 persons shall not reduce its monitoring to less than one (1) sample per treatment plant per year.
System using only groundwater not under direct influence of surface water, using chemical disinfectant, and serving at least 10,000 persons.	TTHM annual average £0.040 mg/L and HAA5 annual average £0.030 mg/L.	One (1) sample per treatment plant per year at distribution system location reflecting maximum residence time during month of warmest water temperature.
System using only groundwater not under direct influence of surface water, using chemical disinfectant, and serving fewer than 10,000 persons.	TTHM annual average £0.040 mg/L and HAA5 annual average £0.030 mg/L for two (2) consecutive years, or TTHM annual average £0.020 mg/L and HAA5 annual average £0.015 mg/L for one (1) year.	One (1) sample per treatment plant per three (3) year monitoring cycle at distribution system location reflecting maximum residence time during month of warmest water temperature, with the three (3) year cycle beginning on January 1 following quarter in which system qualifies for reduced monitoring.