Section 327IAC8-2.5-7. Compliance requirements; disinfectants and disinfection byproducts

   (a) General compliance requirements for disinfectants and disinfection byproducts are as follows:

(1) Where compliance is based on a running annual average of monthly or quarterly samples or averages and the:

(A) 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; and

(B) 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 this rule 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 section 6 of this rule, any particular quarter's average will cause the running annual average of that system to exceed the MCL, the system is out of compliance at the end of that quarter.

  (b) Compliance requirements for disinfection byproducts are as follows:

(1) PWSs shall comply with the compliance requirements for TTHMs and HAA5 until the compliance date specified in section 11(c) of this rule as follows:

(A) For systems monitoring quarterly, compliance with MCLs in section 2(a) of this rule will be based on a running annual arithmetic average, computed quarterly, of quarterly arithmetic averages of all samples collected by the system according to section 6(b)(1) of this rule.

(B) For systems monitoring less frequently than quarterly, systems demonstrate MCL compliance according to the following:

(i) If the average of samples taken that year under section 6(b)(1) of this rule does not exceed the MCLs in section 2 of this rule.

(ii) If the average of the samples taken under item (i) exceeds the MCL, the system:

(AA) shall increase monitoring to once per quarter per treatment plant; and

(BB) is not 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 is in violation at the end of that quarter.

Systems 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.

(C) If the running annual arithmetic average of quarterly averages covering any consecutive four (4) quarter period exceeds the MCL, the system:

(i) is in violation of the MCL; and

(ii) shall notify the public under 327 IAC 8-2.1-7, in addition to reporting to the commissioner under section 8 of this rule.

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

(2) Compliance requirements for bromate will be based on a running annual arithmetic average, computed quarterly, of:

(A) monthly samples; or

(B) for months in which the system takes more than one (1) sample, the average of all samples taken during the month;

collected by the system according to section 6(b)(3) of this rule. If the average of samples covering any consecutive four (4) quarter period exceeds the MCL, the system is in violation of the MCL and shall notify the public under 327 IAC 8-2.1-7, in addition to reporting to the agency under section 8 of this rule. If a PWS fails to complete twelve (12) consecutive months of monitoring, compliance with the MCL for the last four (4) quarter compliance period must be based on an average of the available data.

(3) Compliance requirements for chlorite will be based on an arithmetic average of each three (3) sample set taken in the distribution system according to section 6(b)(2)(A)(ii) and 6(b)(2)(B) of this rule. If the arithmetic average of any three (3) sample sets exceeds the MCL, the system:

(A) is in violation of the MCL; and

(B) shall notify the public under 327 IAC 8-2.1-3 through 327 IAC 8-2.1-17, in addition to reporting to the commissioner under section 8 of this rule.

  (c) Compliance requirements for disinfectant residuals are as follows:

(1) Compliance requirements for chlorine and chloramines are as follows:

(A) Compliance will be based on a running annual arithmetic average, computed quarterly, of monthly averages of all samples collected by the system under section 6(c)(1) of this rule. If the average covering any consecutive four (4) quarter period exceeds the MRDL, the system:

(i) is in violation of the MRDL; and

(ii) shall notify the public under 327 IAC 8-2.1-7, in addition to reporting to the commissioner under section 8 of this rule.

(B) Where systems switch between the use of chlorine and chloramines for residual disinfection during the year:

(i) compliance must be determined by including all monitoring results of both chlorine and chloramines in calculating compliance; and

(ii) reports submitted under section 8 of this rule must clearly indicate which residual disinfectant was analyzed for each sample.

(2) Compliance requirements for chlorine dioxide are as follows:

(A) Compliance requirements for acute violations are as follows:

(i) Compliance will be based on consecutive daily samples collected by the system under section 6(c)(2) of this rule.

(ii) If any 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 exceed the MRDL, the system is in violation of the MRDL and shall:

(AA) take immediate corrective action to lower the level of chlorine dioxide below the MRDL; and

(BB) notify the public under the procedures for acute health risks in 327 IAC 8-2.1-3 through 327 IAC 8-2.1-17.

(iii) 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 result in the following:

(AA) Be considered an MRDL violation.

(BB) The system shall notify the public of the violation in accordance with the provisions for acute violations under 327 IAC 8-2.1-7 through 327 IAC 8-2.1-17, in addition to reporting to the commissioner under section 8 of this rule.

(B) Compliance requirements for nonacute violations are as follows:

(i) Compliance will be based on consecutive daily samples collected by the system under section 6(c)(2) of this rule.

(ii) If any 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 is in violation of the MRDL and shall:

(AA) take corrective action to lower the level of chlorine dioxide below the MRDL at the point of sampling; and

(BB) notify the public under the procedures for nonacute health risks in 327 IAC 8-2.1-7 through 327 IAC 8-2.1-17, in addition to reporting to the commissioner under section 8 of this rule.

(iii) 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 will result in the following:

(AA) Be considered an MRDL violation.

(BB) The system shall notify the public of the violation in accordance with the provisions for nonacute violations under 327 IAC 8-2.1-7, in addition to reporting to the commissioner under section 8 of this rule.

  (d) Compliance for disinfection byproduct precursors (DBPP) are as follows:

(1) Compliance will be determined as specified by section 9 of this rule.

(2) Systems may begin monitoring to determine whether Step 1 TOC removals can be met twelve (12) months before 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:

(A) does not monitor during this period; and

(B) then determines in the first twelve (12) months after the compliance date that it is not able to meet the Step 1 requirements in section 9(b)(2) 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 by section 9(b)(3) of this rule and is in violation.

(3) Systems may apply for alternate minimum TOC removal (Step 2) requirements any time after the compliance date, unless under subdivision (2) the system is not eligible.

(4) For systems required to meet Step 1 TOC removals, if the value calculated under section 9(c)(1)(D) of this rule is less than one and zero-hundredths (1.00), the system:

(A) is in violation of the treatment technique requirements under section 9 of this rule; and

(B) shall notify the public under 327 IAC 8-2.1-7 through 327 IAC 8-2.1-17, in addition to reporting to the commissioner under section 8 of this rule.

(Water Pollution Control Division; 327 IAC 8-2.5-7; filed May 1, 2003, 12:00 p.m.: 26 IR 2847; filed Oct 24, 2006, 3:03 p.m.: 20061122-IR-327050255FRA; filed May 7, 2010, 9:30 a.m.: 20100602-IR-327080198FRA)