Tenn. Comp. R. & Regs. 0400-45-01-.36

Current through October 22, 2024

Section 0400-45-01-.36 - DISINFECTANT RESIDUALS, DISINFECTION BYPRODUCTS, AND DISINFECTION BYPRODUCT PRECURSORS

(1) The requirements of this rule constitute national primary drinking water regulations.

General Requirements.

(a) The regulations in this rule establish criteria under which community water systems (CWSs) and non-transient, non-community water systems (NTNCWSs) which add a chemical disinfectant to the water in any part of the drinking water treatment process or which provide water that contains a chemical disinfectant, must modify their practices to meet MCLs and MRDLs in Rule 0400-45-01-.06 and must meet the treatment technique requirements for disinfection byproduct precursors in this rule.

(b) The regulations in this rule establish criteria under which transient NCWSs that use chlorine dioxide as a disinfectant or oxidant must modify their practices to meet the MRDL for chlorine dioxide in Rule 0400-45-01-.06.

(c) EPA has established MCLs for TTHM and HAA5 and treatment technique requirements for disinfection byproduct precursors to limit the levels of known and unknown disinfection byproducts which may have adverse health effects. These disinfection byproducts may include chloroform; bromodichloromethane; dibromochloromethane; bromoform; dichloroacetic acid; and trichloroacetic acid.

(2) Compliance dates.

(a) CWSs and NTNCWSs. Unless otherwise noted, systems must comply with the requirements of this rule as follows: Subpart H systems serving 10,000 or more persons must comply with this rule beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons and systems using only ground water not under the direct influence of surface water must comply with this rule beginning January 1, 2004.

(b) Transient NCWSs. Subpart H 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 beginning January 1, 2002. Subpart H systems serving fewer than 10,000 persons 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 beginning January 1, 2004.

(3) Each CWS and NTNCWS regulated under subparagraph (1)(a) of this rule must be operated by qualified personnel who meet the requirements specified by the Department.

(4) Control of disinfectant residuals. Notwithstanding the MRDLs in Rule 0400-45-01-.06, systems may increase residual disinfectant levels of chlorine and chloramines (but not chlorine dioxide) in the distribution system 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.

(5) Reserved

(6) Monitoring Requirements

(a) General requirements.

1. Systems must take all samples during normal operating conditions.

2. Systems after obtaining Department approval 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.

3. Failure to monitor in accordance with the monitoring plan required by this rule is a monitoring violation.

4. 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.

5. Systems may use only data collected under the provisions of this rule to qualify for reduced monitoring.

(b) Monitoring requirements for disinfection byproducts.

1. TTHMs and HAA5.

(i) Routine monitoring. Systems must monitor at the frequency indicated in the following table:

Routine Monitoring Frequency for TTHM and HAA5

Type of System	Minimum Monitoring Frequency	Sample location in the distribution system
Subpart H system serving at least 10,000 persons	Four water samples per quarter per treatment plant	At least 25 percent of all samples collected each quarter at locations representing maximum residence time. Remaining samples taken at locations representative of at least average residence time in the distribution system and representing the entire distribution system, taking into account number of persons served, different sources of water and different treatment methods.1
Subpart H systems serving 500 to 9,999 persons.	One water sample per quarter per treatment plant	Locations representing the maximum residence time.1
Subpart H systems serving fewer than 500 persons.	One 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 sample is taken) exceeds MCL, the system must increase monitoring to one sample per quarter, taken at a point reflecting the maximum residence time in the distribution system, until system meets reduced monitoring criteria in subpart (iv) of this part for reduced monitoring..
System using only ground water not under direct influence of surface water using chemical disinfectant and serving at least 10,000 persons	One water sample per quarter per treatment plant. 2	Locations representing maximum residence time.1
Systems using only ground water not under the direct influence of surface water using a chemical disinfectant and serving fewer than 10,000 persons	One sample per year per treatment plant2 during month of the warmest water temperature.	Locations representing maximum residence time.1 If the sample (or average of annual samples, if more than one sample is taken) exceeds the MCL, the system must increase monitoring to one sample per treatment plant per quarter, taken at a point reflecting the maximum residence time in the distribution system, until system meets criteria for reduced monitoring described in subpart (iv) of this part for reduced monitoring.

¹ If a system elects to sample more frequently than the minimum required, at least 25 percent of all samples collected each quarter (including those taken in excess of the required frequency) must be taken at locations that represent the maximum residence time of the water in the distribution system. The remaining samples must be taken at locations representative of at least average residence time in the distribution system.

² Multiple wells drawing water from a single aquifer may be considered one treatment plant for determining the minimum number of samples required, with Department approval in accordance with criteria approved by the Department.

(ii) Systems may reduce monitoring, except as otherwise provided, in accordance with the following table:

Reduced Monitoring Frequency for TTHM and HAA5

If you are a ...	You may reduce monitoring if you have monitored at least one year and your ...	To this level
Subpart H systems serving at least 10,000 persons which has a source water annual average TOC level before any treatment, 4.0mg/L.	TTHM annual average 0.040 mg/L and HAA5 annual average 0.030 mg/L.	One sample per treatment plant per quarter at distribution system location reflecting maximum residence time.
Subpart H system serving from 500 to 9,999 persons which has a source water annual average TOC level before any treatment. 4.0 mg/L.	TTHM annual average 0.040 mg/L and HAA5 annual average 0.030 mg/L.	One sample per treatment plant per year at distribution system location reflecting maximum residence time during month of warmest water temperature.
Subpart H system serving fewer than 500 persons		Subpart H systems serving fewer than 500 persons may not reduce its monitoring to less than one sample per treatment plant per year.
System using only ground water 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 sample per treatment plant per year at distribution system location reflecting maximum residence time during month of warmest water temperature.
System using only ground water 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 consecutive years OR TTHM annual average of 0.020 mg/L and HAA5 annual average 0.015 mg/L for one year.	One sample per treatment plant per three year monitoring cycle at distribution system location reflecting maximum residence time during month of warmest water temperature, with the three-year cycle beginning on January 1 following quarter in which system qualifies for reduced monitoring.

(iii) Monitoring requirements for source water TOC. In order to qualify for reduced monitoring for TTHM and HAA5 under subpart (ii) of this part, subpart H systems not monitoring under the provisions of subparagraph (d) of this paragraph must take monthly TOC samples every 30 days at a location prior to any treatment, beginning April 1, 2008 or earlier, if specified by the Department. In addition to meeting other criteria for reduced monitoring in subpart (ii) of this part, the source water TOC running annual average must be less than or equal to 4.0 mg/L (based on the most recent four quarters of monitoring) on a continuing basis at each treatment plant to reduce or remain on reduced monitoring for TTHM and HAA5. Once qualified for reduced monitoring for TTHM and HAA5 under subpart (ii) of this part, a system may reduce source water TOC monitoring to quarterly TOC samples taken every 90 days at a location prior to any treatment.

(iv) Systems on a reduced monitoring schedule may remain on that reduced schedule as long as the average of all samples taken in the year (for systems which must monitor quarterly) or the result of the sample (for systems which must monitor no more frequently than annually) is no more than 0.060 mg/L and 0.045 mg/L for TTHMs and HAA5, respectively. Systems that do not meet these levels must resume monitoring at the frequency identified in paragraph (b)(1)(i) of this section (minimum monitoring frequency column) in the quarter immediately following the monitoring period in which the system exceeds 0.060 mg/L or 0.045 mg/L for TTHMs and HAA5, respectively. For systems using only ground water not under the direct influence of surface water and serving 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 must go to the increased monitoring identified in subpart (i) of this part (sample location column) in the quarter immediately following the monitoring period in which the system exceeds 0.080 mg/L or 0.060 mg/L for TTHMs or HAA5 respectively.

(v) Systems on increased monitoring may return to routine monitoring if TTHM annual average is equal to or less than 0.040 mg/L and HAA5 is less than or equal to 0.030 mg/L.

(vi) The Department may return a system to routine monitoring at the Department's discretion.

2. Chlorite. Community and nontransient noncommunity water systems using chlorine dioxide, for disinfection or oxidation, must conduct monitoring for chlorite.

(i) Routine Monitoring

(I) Daily monitoring. Systems must take daily samples at the entrance to the distribution system. For any daily sample that exceeds the chlorite MCL, the system must take additional samples in the distribution system the following day at the locations required by subpart (ii) of this part, in addition to the sample required at the entrance to the distribution system.

(II) Monthly monitoring. Systems must take a three-sample set each month in the distribution system. The system must take one sample at each of the following locations: near the first customer, at a location representative of average residence time, and at a location reflecting maximum residence time in the distribution system. Any additional routine sampling must be conducted in the same manner (as three-sample sets, at the specified locations). The system may use the results of additional monitoring conducted under subpart (ii) of this part to meet the requirement for monitoring in this paragraph.

(ii) 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 is required to take three chlorite distribution system samples at the following locations: as close to the first customer as possible, in a location representative of average residence time, and as close to the end of the distribution system as possible (reflecting maximum residence time in the distribution system).

(iii) Reduced monitoring.

(I) Chlorite monitoring at the entrance to the distribution system required by item (i)(I) of this part may not be reduced.

(II) Chlorite monitoring in the distribution system required by item (i)(II) of this part may be reduced to one three-sample set per quarter after one year of monitoring where no individual chlorite sample taken in the distribution system under item (i)(II) of this part has exceeded the chlorite MCL and the system has not been required to conduct monitoring under subpart (ii) of this part. The system may remain on the reduced monitoring schedule until either any of the three individual chlorite samples taken quarterly in the distribution system under item (i)(II) of this part exceeds the chlorite MCL or the system is required to conduct monitoring under subpart (ii) of this part, at which time the system must revert to routine monitoring.

3. Bromate

(i) Routine monitoring. Community and nontransient noncommunity systems using ozone, for disinfection or oxidation, must take one sample per month for each treatment plant in the system using ozone. Systems must take samples monthly at the entrance to the distribution system while the ozonation system is operating under normal conditions.

(ii) Reduced monitoring.

(I) Until March 31, 2009, systems required to analyze for bromate may reduce monitoring from monthly to quarterly, if the system's average source water bromide concentration is less than 0.05 mg/L based on representative monthly bromide measurements for one year. 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 on representative monthly measurements. If the running annual average source water bromide concentration is greater than or equal to 0.05 mg/L, the system must resume routine monitoring required by subpart (i) of this part in the following month.

(II) Beginning April 1, 2009, systems may no longer use the provisions of item (I) of this subpart to qualify for reduced monitoring. A system required to analyze for bromate may reduce monitoring from monthly to quarterly, if the system's running annual average bromate concentration is less than or equal to 0.0025 mg/L based on monthly bromate measurements under subpart (i) of this part for the most recent four quarters, with samples analyzed using Method 317.0 Revision 2.0, 326.0 or 321.8. If a system has qualified for reduced bromate monitoring under item (I) of this subpart, that system may remain on reduced monitoring as long as the running annual average of quarterly bromate samples is less than or equal to 0.0025 mg/L based on samples analyzed using Method 317.0 Revision 2.0, 326.0, or 321.8. If the running annual average bromate concentration is >0.0025 mg/L, the system must resume routine monitoring required by subpart (i) of this part.

(c) Monitoring requirements for disinfectant residuals.

1. Chlorine and chloramines.

(i) 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 points in the distribution system and at the same time as total coliforms are sampled, as specified in Rule 0400-45-01-.07. 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 paragraphs (4) through (8) of Rule 0400-45-01-.41. Subpart H systems may use the results of residual disinfectant concentration sampling conducted under part 6 of subparagraph (b) of paragraph (5) of Rule 0400-45-01-.31 for unfiltered systems or part 3 of subparagraph (c) of paragraph (5) of Rule 0400-45-01-.31 for systems which filter, in lieu of taking separate samples.

(ii) Reduced monitoring. Monitoring may not be reduced.

2. Chlorine dioxide.

(i) Routine monitoring. Community, nontransient noncommunity, and transient noncommunity water systems that use chlorine dioxide for disinfection or oxidation must take daily samples at the entrance to the distribution system. For any daily sample that exceeds the MRDL, the system must take samples in the distribution system the following day at the locations required by subpart (ii) of this part, in addition to the sample required at the entrance to the distribution system.

(ii) Additional monitoring. On each day following a routine sample monitoring result that exceeds the MRDL, the system is required to take three chlorine dioxide distribution system samples. If chlorine dioxide or chloramines are 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 no disinfection addition points after the entrance to the distribution system (i.e., no booster chlorination), the system must take three samples as close to the first customer as possible, at intervals of at least six hours. If chlorine is used to maintain a disinfectant residual in the distribution system and there are one or more disinfection addition points after the entrance to the distribution system, (i.e., booster chlorination), the system must take one sample at each of the following locations: as close to the first customer as possible, in a location representative of average residence time, and as close to the end of the distribution system as possible (reflecting maximum residence time in the distribution system).

(iii) Reduced monitoring. Chlorine dioxide monitoring may not be reduced.

(d) Monitoring requirements for disinfection byproduct precursors DBPP).

1. Routine monitoring. Subpart H systems which use conventional filtration treatment (as defined in Rule 0400-45-01-.04) must monitor each treatment plant for TOC no later than the point of combined filter effluent turbidity monitoring and representative of the treated water. All systems required to monitor under this part must also monitor for TOC in the source water prior to any treatment at the same time as monitoring for TOC in the treated water. These samples (source water and treated water) are referred to as paired samples. At the same time as the source water sample is taken, all systems must monitor for alkalinity in the source water prior to any treatment. Systems must take one paired sample and one source water alkalinity sample per month per plant at a time representative of normal operating conditions and influent water quality.

2. Reduced monitoring. Subpart H systems with an average treated water TOC of less than 2.0 mg/L for two consecutive years, or less than 1.0 mg/L for one year, may reduce monitoring for both TOC and alkalinity to one paired sample and one source water alkalinity sample per plant per quarter. The system must revert to routine monitoring in the month following the quarter when the annual average treated water TOC is greater than or equal to 2.0 mg/L.

(e) Bromide. Systems 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 year. The system must continue bromide monitoring to remain on reduced bromate monitoring.

(f) Monitoring plans. Each system required to monitor under this paragraph must develop and implement a monitoring plan. The system must maintain the plan and make it available for inspection by the Department and the general public no later than 30 days following the applicable compliance dates in paragraph (2) of this rule. All Subpart H systems serving more than 3300 people must submit a copy of the monitoring plan to the Department no later than the date of the first report required under paragraph (8) of this rule. The Department may also require the plan to be submitted by any other system. After review, the Department may require changes in any plan elements. The plan must include at least the following elements.

1. Specific locations and schedules for collecting samples for any parameters included in this rule.

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

3. 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.

(7) Compliance requirements.

(a) General requirements.

1. Where 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 will be treated as a monitoring 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 MRDLs for chlorine and chloramines, this failure to monitor will be treated as a monitoring violation for the entire period covered by the annual average.

2. All samples taken and analyzed under the provisions of this paragraph must be included in determining compliance, even if that number is greater than the minimum required.

3. If, during the first year of monitoring under paragraph (6) of this rule, any individual quarter's average will cause the running annual average of that system to exceed the MCL for total trihalomethanes, haloacetic acids (five) or bromate; or the MRDL for chlorine or chloramines, the system is out of compliance at the end of that quarter.

(b) Disinfection byproducts.

1. TTHMs and HAA5.

(i) For systems monitoring quarterly, compliance with MCLs in Rule 0400-45-01-.06 must be based on a running annual arithmetic average, computed quarterly, of quarterly arithmetic averages of all samples collected by the system as prescribed by part (6)(b)1 of this rule.

(ii) For systems monitoring less frequently than quarterly, systems demonstrate MCL compliance if the average of samples taken that year under the provisions of part (6)(b)1 of this rule does not exceed the MCLs in Rule 0400-45-01-.06. If the average of these samples exceeds the MCL, the system must increase monitoring to once per quarter per treatment plant and is not in violation of the MCL until it has completed one year of quarterly monitoring, unless the result of fewer than four quarters of monitoring will cause the running annual average to exceed the MCL, in which case the system is in violation at the end of that quarter. Systems required to increase to quarterly monitoring must calculate compliance by including the sample which triggered the increased monitoring plus the following three quarters of monitoring results.

(iii) If the running annual arithmetic average of quarterly averages covering any consecutive four-quarter period exceeds the MCL, the system is in violation of the MCL and must notify the public pursuant to Rule 0400-45-01-.19 and report to the Department pursuant to paragraph (8) of this rule.

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

2. Bromate. Compliance must be based on a running annual arithmetic average, computed quarterly, of monthly samples (or, for months in which the system takes more than one sample, the average of all samples taken during the month) collected by the system as prescribed by part (6)(b)3 of this rule. If the average of samples covering any consecutive four-quarter period exceeds the MCL, the system is in violation of the MCL and must notify the public pursuant to Rule 0400-45-01-.19, in addition to reporting to the Department pursuant to paragraph (8) of this rule. If a PWS fails to complete 12 consecutive months of monitoring, compliance with the MCL for the last four-quarter compliance period must be based on an average of the available data.

3. Chlorite. Compliance must be based on an arithmetic average of each three sample set taken in the distribution system as prescribed by item (6)(b)2(i)(II) and subpart (6)(b)2(ii) of this rule. If the arithmetic average of any three sample set exceeds the MCL, the system is in violation of the MCL and must notify the public pursuant to Rule 0400-45-01-.19, in addition to reporting to the Department pursuant to paragraph (8) of this rule.

(c) Disinfectant residuals.

1. Chlorine and chloramines.

(i) Compliance must be based on a running annual arithmetic average, computed quarterly, of monthly averages of all samples collected by the system under part (6)(c)1 of this rule. If the average of quarterly averages covering any consecutive four-quarter period exceeds the MRDL, the system is in violation of the MRDL and must notify the public pursuant to Rule 0400-45-01-.19, in addition to reporting to the Department pursuant to paragraph (8) of this rule.

(ii) In cases where systems switch between the use of chlorine and chloramines for residual disinfection during the year, compliance must be determined by including together all monitoring results of both chlorine and chloramines in calculating compliance. Reports submitted pursuant to paragraph (8) of this rule must clearly indicate which residual disinfectant was analyzed for each sample.

2. Chlorine dioxide.

(i) Acute violations. Compliance must be based on consecutive daily samples collected by the system under this rule. If any daily sample taken at the entrance to the distribution system exceeds the MRDL, and on the following day one (or more) of the three samples taken in the distribution system exceed the MRDL, the system is in violation of the MRDL and must take immediate corrective action to lower the level of chlorine dioxide below the MRDL and must notify the public pursuant to the procedures for acute health risks in Rule 0400-45-01-.19, in addition to reporting to the Department pursuant to paragraph (8) of this rule. 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 will also be considered an MRDL violation and the system must notify the public of the violation in accordance with the provisions for acute violations under Rule 0400-45-01-.19, in addition to reporting to the Department pursuant to paragraph (8) of this rule.

(ii) Nonacute violations. Compliance must be based on consecutive daily samples collected by the system under part (6)(c)2 of this rule. If any two 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 is in violation of the MRDL and must take corrective action to lower the level of chlorine dioxide below the MRDL at the point of sampling and will notify the public pursuant to the procedures for nonacute health risks in Rule 0400-45-01-.19, in addition to reporting to the Department pursuant to paragraph (8) of this rule. 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 is also an MRDL violation and the system must notify the public of the violation in accordance with the provisions for nonacute violations under Rule0400-45-01-.19, in addition to reporting to the Department pursuant to paragraph (8) of this rule.

(d) Disinfection byproduct precursors (DBPP). Compliance must be determined as specified by subparagraph (9)(b) of this rule. Systems may begin monitoring to determine whether Step 1 TOC removals can be met 12 months prior to the compliance date for the system. This monitoring is not required and failure to monitor during this period is not a violation. However, any system that does not monitor during this period, and then determines in the first 12 months after the compliance date that it is not able to meet the Step 1 requirements in subparagraph (9)(b) of this rule and must therefore apply for alternate minimum TOC removal (Step 2) requirements, is not eligible for retroactive approval of alternate minimum TOC removal (Step 2) requirements as allowed pursuant to subparagraph (9)(c) of this rule and is in violation. Systems may apply for alternate minimum TOC removal (Step 2) requirements any time after the compliance date. For systems required to meet Step 1 TOC removals, if the value calculated under paragraph (9) of this rule is less than 1.00, the system is in violation of the treatment technique requirements and must notify the public pursuant to Rule 0400-45-01-.19, in addition to reporting to the Department pursuant to paragraph (8) of this rule.

(8) Reporting and recordkeeping requirements.

(a) Systems required to sample quarterly or more frequently must report to the Department within 10 days after the end of each quarter in which samples were collected, notwithstanding the provisions of Rule 0400-45-01-.18. Systems required to sample less frequently than quarterly must report to the Department within 10 days after the end of each monitoring period in which samples were collected.

(b) Disinfection byproducts. Systems must report the information specified in the following table:

If you are a	You must report 1
System monitoring for TTHM and HAA5 under the requirements of subparagraph (6)(b) of this rule on a quarterly or more frequent basis.	(1) The number of samples taken during the last quarter. (2) The location, date, 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 averages for the last four quarters. (5) Whether the MCL was exceeded.
System monitoring for TTHMs and HAA5 under the requirements of subparagraph (6)(b) of this rule less frequently than quarterly (but at least annually).	(1) The number of samples taken during the last year. (2) The location, date and result of each sample taken during the last monitoring period. (3) The arithmetic average of all samples taken during the last year. (4) Whether the MCL was exceeded..
System monitoring for TTHMs and HAA5 under the requirements of subparagraph (6)(b) of this rule less frequently than annually.	(1) The location, date, and result of the last sample taken. (2) Whether the MCL was exceeded.
Systems monitoring for Chlorite under subparagraph (6)(b) of this rule.	(1) The number of samples taken the last quarter. (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. (4) Whether the MCL was exceeded and in which month it was exceeded.
Systems monitoring for Bromate under the requirements of subparagraph (6)(b) of this rule.	(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. (4) Whether the MCL was exceeded.

(c) Disinfectants. Systems must report the following information specified in the following table:

If you are a	You must report
System monitoring for chlorine or chloramines under the requirements of subparagraph (6)(c) of this rule.	(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 months. (3) The arithmetic average of all monthly averages for the last twelve months. (4) Whether the MRDL was exceeded.
System monitoring for chlorine dioxide under the requirements of subparagraph (6)(c) of this rule.	(1) The dates, results, and locations of samples taken during the last quarter. (2) Whether the MRDL was exceeded. (3) Whether the MRDL was exceeded in any two consecutive daily samples and whether the resulting violation was acute or nonacute.

(d) Disinfection byproduct precursors and enhanced coagulation or enhanced softening. System must report the information specified in the following table:

If you are a	You must report
System monitoring monthly or quarterly for TOC under the requirements of subparagraph (6)(d) of this rule and required to meet the enhanced coagulation or enhanced softening requirements in part (9)(b)2 or 3 of this rule.	(1) The number of paired (source and treated water, prior to continuous disinfection) samples taken during the last quarter. (2) The location, date and results 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 part (9)(c)1 of this rule. (5) Whether the system is in compliance with the enhanced coagulation or enhanced softening percent removal requirements in subparagraph (9)(b) of this rule for the last four quarters.
System monitoring monthly or quarterly for TOC under the requirements of subparagraph (6)(d) of this rule and meeting one or more of the alternative compliance criteria in part (9)(a)2 or 3 of this rule.	(1) The alternate compliance criteria the system is using. (2) The number of paired samples taken during the last quarter. (3) The location, date, and results of each paired sample and association alkalinity taken during the last quarter. (4) The running annual arithmetic average based on monthly averages (or quarterly samples) of source water TOC for systems meeting a criterion in subpart (9)(a)2(i) or (iii) of this rule or of treated water TOC for system meeting the criterion in subpart (9)(a)2(ii) of this rule. (5) The running annual arithmetic average based on monthly averages (or quarterly samples) of source water SUVA for systems meeting the criterion in subpart (9)(a)2(v) of this rule or of treated water SUVA for system meeting the criterion in subpart (9)(a)2(vi) of this rule. (6) The running annual average of source water alkalinity for systems meeting the criterion in subpart (9)(a)2(iii) of this rule and of treated water alkalinity for systems meeting the criterion in subpart (9)(a)3(i) of this rule. (7) The running annual average for both TTHM and HAA5 for systems meeting the criterion in subpart (9)(a)2(iii) or (iv) of this rule. (8) The running annual average of the amount of magnesium hardness removal (as CaCO3, in mg/L) for systems meeting the criterion in subpart (9)(a)3(ii) of this rule. (9) Whether the system is in compliance with the particular alternative compliance criterion in part (9)(a)2 or 3 of this rule.

(9) Treatment technique for control of disinfection byproduct (DBP) precursors.

(a) Applicability.

1. Subpart H systems using conventional filtration treatment (as defined in Rule 0400-45-01-.04) must operate with enhanced coagulation or enhanced softening to achieve the TOC percent removal levels specified in subparagraph (b) of this paragraph unless the system meets at least one of the alternative compliance criteria listed in part 2 or 3 of this subparagraph.

2. Alternative compliance criteria for enhanced coagulation and enhanced softening systems. Subpart H systems using conventional filtration treatment may use the alternative compliance criteria in subparts (i) through (vi) of this part to comply with this subparagraph in lieu of complying with subparagraph (b) of this paragraph. Systems must still comply with monitoring requirements in subparagraph (6)(d) of this rule.

(i) The system's source water TOC level, measured according to part (5)(d)3 of this rule, is less than 2.0 mg/L, calculated quarterly as a running annual average.

(ii) The system's treated water TOC level, measured according to part (5)(d)3 of this rule, is less than 2.0 mg/L, calculated quarterly as a running annual average.

(iii) The system's source water TOC level, measured according to part (5)(d)3 of this rule, is less than 4.0 mg/L, calculated quarterly as a running annual average; the source water alkalinity, measured according to part (5)(d)1 of this rule, is greater than 60 mg/L (as CaCO₃), calculated quarterly as a running annual average; and either the TTHM and HAA5 running annual averages are no greater than 0.040 mg/L and 0.030 mg/L, respectively; or prior to the effective date for compliance in paragraph (2) of this rule, the system has made a clear and irrevocable financial commitment not later than the effective date for compliance in paragraph (2) of this rule to use of technologies that will limit the levels of TTHMs and HAA5 to no more than 0.040 mg/L and 0.030 mg/L, respectively. Systems must submit evidence of a clear and irrevocable financial commitment, in addition to a schedule containing milestones and periodic progress reports for installation and operation of appropriate technologies, to the Department for approval not later than the effective date for compliance in paragraph (2) of this rule. These technologies must be installed and operating not later than June 16, 2005. Failure to install and operate these technologies by the date in the approved schedule will constitute a violation of National Primary Drinking Water Regulations.

(iv) The TTHM and HAA5 running annual averages are no 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.

(v) The system's source water SUVA, prior to any treatment and measured monthly according to part (5)(d)4 of this rule, is less than or equal to 2.0 L/mg-m, calculated quarterly as a running annual average.

(vi) The system's finished water SUVA, measured monthly according to part (5)(d)4 of this rule, is less than or equal to 2.0 L/mg-m, calculated quarterly as a running annual average.

3. Additional alternative compliance criteria for softening systems. Systems practicing enhanced softening that cannot achieve the TOC removals required by part (9)(b)2 of this rule may use the alternative compliance criteria in subparts (9)(a)3(i) and (ii) of this rule in lieu of complying with subparagraph (9)(b) of this rule. Systems must still comply with monitoring requirements in subparagraph (6)(d) of this rule.

(i) Softening that results in lowering the treated water alkalinity to less than 60 mg/L (as CaCO₃), measured monthly according to part (5)(d)1 of this rule, and calculated quarterly as a running annual average.

Softening that results in removing at least 10 mg/L of magnesium hardness (as CaCO3), measured monthly according to part (5)(d)6 of this rule and calculated quarterly as a running annual average.

(b) Enhanced coagulation and enhanced softening performance requirements.

1. Systems must achieve the percent reduction of TOC specified in part (9)(b)2 of this rule between the source water and the combined filter effluent, unless the Department approves a system's request for alternate minimum TOC removal (Step 2) requirements under part (9)(b)3 of this rule.

2. Required Step 1 TOC reductions, indicated in the following table, are based upon specified source water parameters measured in accordance with subparagraph (5)(d) of this rule. Systems practicing softening are required to meet the Step 1 TOC reductions in the far-right column (Source water alkalinity >120 mg/L) for the specified source water TOC:

Step 1 Required Removal of TOC in Percent Removal by Enhanced Coagulation and Enhanced Softening for Subpart H Systems Using Conventional Treatment ^{1, 2}

Source Water TOC, mg/L	Source Water Alkalinity,mg/L as CaCO3
	0-60	>60-120	1203
2.0-4.0	35.0%	25.0%	15.0%
4.0-8.0	45.0%	35.0%	25.0%
8.0	50.0%	40.0%	30.0%

¹ Systems meeting at least one of the conditions in subparts (9)(a)(2)(i) through (vi) of this rule are not required to operate with enhanced coagulation.

² Softening systems meeting one of the alternative compliance criteria in part (9)(a)3 of this rule are not required to operate with enhanced softening.

³ Systems practicing softening must meet the TOC removal requirements in this column.

3. Subpart H conventional treatment systems that cannot achieve the Step 1 TOC removals required by part (9)(b)2 of this rule due to water quality parameters or operational constraints must apply to the Department, within three months of failure to achieve the TOC removals required by part 2 of this subparagraph, for approval of alternative minimum TOC (Step 2) removal requirements submitted by the system. If the Department approves the alternative minimum TOC removal (Step 2) requirements, the Department may make those requirements retroactive for the purposes of determining compliance. Until the Department approves the alternate minimum TOC removal (Step 2) requirements, the system must meet the Step 1 TOC removals contained in part 2 of this subparagraph.

4. Alternate minimum TOC removal (Step 2) requirements. Applications made to the Department by enhanced coagulation systems for approval of alternative minimum TOC removal (Step 2) requirements under part (9)(b)3 of this rule must include, as a minimum, results of bench- or pilot-scale testing conducted under subpart (9)(b)4(i) of this rule and used to determine the alternate enhanced coagulation level. The submitted bench or pilot scale testing must be used to determine the alternate enhanced coagulation level.

(i) Alternate enhanced coagulation level is defined as coagulation at a coagulant dose and pH as determined by the method described in subpart (9)(b)4(i) through (v) of this rule such that an incremental addition of 10 mg/L of alum (as aluminum) (or equivalent amount of ferric salt) results in a TOC removal of 0.3 mg/L. The percent removal of TOC at this point on the TOC removal versus coagulant dose curve is then defined as the minimum TOC removal required for the system. Once approved by the Department, this minimum requirement supersedes the minimum TOC removal required by the table in part 2 of this subparagraph. This requirement will be effective until such time as the Department approves a new value based on the results of a new bench- and pilot-scale test. Failure to achieve Department-set alternative minimum TOC removal levels is a violation of National Primary Drinking Water Regulations.

(ii) Bench- or pilot-scale testing of enhanced coagulation must be conducted by using representative water samples and adding 10 mg/L increments of alum (as aluminum) (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 as CaCO3)	Target pH
0-60	5.5
>60-120	6.3
>120-240	7.0
>240	7.5

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

(iv) The system may operate at any coagulant dose or pH necessary (consistent with other NPDWRs) to achieve the minimum TOC percent removal approved under part (9)(b)3 of this rule.

(v) If the TOC removal is consistently less than 0.3 mg/L of TOC per 10 mg/L of incremental alum dose (as aluminum) at all dosages of alum (or equivalant addition of iron coagulant), the water is deemed to contain TOC not amenable to enhanced coagulation. The system may then apply to the Department for a waiver of enhanced coagulation requirements.

(c) Compliance calculations.

1. Subpart H systems other than those identified in part (9)(a)2 or 3 of this rule must comply with requirements contained in part (9)(b)2 or 3 of this rule. Systems must calculate compliance quarterly, beginning after the system has collected 12 months of data, by determining an annual average using the following method:

(i) Determine actual monthly TOC percent removal, equal to:

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

(ii) Determine the required monthly TOC percent removal (from either the table in (b)2 of this paragraph or from part (9)(b)3 of this rule).

(iii) Divide the value in subpart (9)(c)1(i) of this rule by the value in subpart (9)(c)1(ii) of this rule.

(iv) Add together the results of subpart (9)(c)1(iii) of this rule for the last 12 months and divide by 12.

(v) If the value calculated in subpart (9)(c)1(iv) of this rule is less than 1.00, the system is not in compliance with the TOC percent removal requirements.

2. Systems may use the provisions in subparts (9)(c)2(i) through (v) of this rule in lieu of the calculations in subparts (9)(c)1(i) through (v) of this rule to determine compliance with TOC percent removal requirements.

(i) In any month that the system's treated or source water TOC level, measured according to part (5)(d)3 of this rule, is less than 2.0 mg/L, the system may assign a monthly value of 1.0 (in lieu of the value calculated in subpart (9)(c)1(iii) of this rule) when calculating compliance under the provisions of part (9)(c)1 of this rule.

(ii) In any month that a system practicing softening removes at least 10 mg/L of magnesium hardness (as CaCO₃), the system may assign a monthly value of 1.0 (in lieu of the value calculated in subpart (9)(c)1(iii) of this rule) when calculating compliance under the provisions of part (9)(c)1 of this rule.

(iii) In any month that the system's source water SUVA, prior to any treatment and measured according to part (5)(d)4 of this rule, is less than or equal to 2.0 L/mg-m, the system may assign a monthly value of 1.0 (in lieu of the value calculated in subpart (9)(c)1(iii) of this rule) when calculating compliance under the provisions of part (9)(c)1 of this rule.

(iv) In any month that the system's finished water SUVA, measured according to part (5)(d)4 of this rule, is less than or equal to 2.0 L/mg-m, the system may assign a monthly value of 1.0 (in lieu of the value calculated in subpart (9)(c)1(iii) of this rule) when calculating compliance under the provisions of part (9)(c)1 of this rule.

(v) In any month that a system practicing enhanced softening lowers alkalinity below 60 mg/L (as CaCO₃), the system may assign a monthly value of 1.0 (in lieu of the value calculated in subpart (9)(c)1(iii) of this rule) when calculating compliance under the provisions of part (9)(c)1 of this rule.

3. Subpart H systems using conventional treatment may also comply with the requirements of this paragraph by meeting the criteria in part (9)(a)2 or 3 of this rule.

(d) Treatment technique requirements for DBP precursors. The Administrator identifies the following as treatment techniques to control the level of disinfection byproduct precursors in drinking water treatment and distribution systems: For Subpart H systems using conventional treatment, enhanced coagulation or enhanced softening.

(10) For purposes of determining enhanced coagulation notwithstanding the provisions of paragraph (9) of this rule the following procedure shall be in force for parent and consecutive systems:

(a) In addition to other prescribed monitoring, all parent (water wholesalers) and consecutive systems using surface water or ground water that has experienced noncompliance with the maximum contaminant levels or exceedances of operational evaluation levels for disinfection byproducts or other systems designated by the Department shall conduct quarterly monitoring for chlorine, pH, disinfection byproducts and other water quality indicators as necessary at or near the master meter having the highest annual arithmetic mean concentration for THMs or HAA5s with all systems reporting their test results to each other. Parent and consecutive systems shall coordinate sampling activities so that samples are collected on the same date or a date prescribed by the department. This paragraph does not apply to emergency or temporary connections.

(b) Based on paragraph (7) of Rule0400-45-01-.38; upon determination of an exceedance of the maximum, contaminant level or operational evaluation level trend calculated by the method described in paragraph (7) of Rule 0400-45-01-.38 in the consecutive system the following measures shall be required:

1. If the parent system TTHM or HAA5 analytical results at or near the master meter are 60% or less of the maximum contaminant limit for THMs and HAA5, no action is required by the parent system. The consecutive system(s) must submit an operational evaluation report to the Department within 90 days of the end of the quarter the operational evaluation calculation is made.

2. If the parent system and/or consecutive system TTHM or HAA5 test results are greater than 60% of the maximum contaminant limit for THMs or HAA5s at the master meter, both the parent system and consecutive system(s) are required to jointly submit the required operational evaluation report including the steps to be implemented to eliminate future exceedances and a schedule for implementation for Department approval.

Tenn. Comp. R. & Regs. 0400-45-01-.36

Original rule filed August 1, 2012; effective October 30, 2012. Rule was previously numbered 1200-05-01. Amendments and new rules filed November 24, 2015; effective 2/22/2016.

Authority: T.C.A. §§ 68-221-701 et seq. and 4-5-201 et seq.