Section 327IAC8-2.5-11. General requirements; stage 2 disinfection byproducts requirements

   (a) The requirements of this section and sections 12 through 20 of this rule establish monitoring and other requirements for achieving compliance with the following:

(1) MCLs based on LRAA for the following:

(A) TTHM.

(B) HAA5.

(2) MRDLs for:

(A) chlorine; and

(B) chloramines;

for certain consecutive systems.

  (b) The requirements of this section and sections 12 through 20 of this rule apply to CWSs and NTNCWS that:

(1) use a primary or residual disinfectant other than ultraviolet light; or

(2) deliver water that has been treated with a primary or residual disinfectant other than ultraviolet light.

  (c) Affected systems shall comply with the requirements in this section and sections 12 through 20 of this rule according to the schedule in the following table, based on system type:

(1) Table 11 provides compliance dates for the following:

(A) Systems that are not part of a combined distribution system and systems that serve the largest population in the combined distribution system.

(B) Other systems that are part of a combined distribution system.

Table 11

If you are this type of system:	The system shall comply with this section and sections 12 through 20 of this rule by:1
The following apply to systems that are not part of a combined distribution system and systems that serve the largest population in the combined distribution system:
System serving ≥ 100,000	April 1, 2012
System serving 50,000 - 99,999	October 1, 2012
System serving 10,000 - 49,999	October 1, 2013
System serving < 10,000	October 1, 2013 if no Cryptosporidium monitoring is required under 327 IAC 8-2.6-8(b)(1); or October 1, 2014 if Cryptosporidium monitoring is required under 327 IAC 8-2.6-8(b)(1)
The following applies to other systems that are part of a combined distribution system:
Consecutive system or wholesale system	The same time as the system with the earliest compliance date in the combined distribution system

¹The commissioner may grant up to an additional twenty-four (24) months for compliance with MCLs and operational evaluation levels if a PWS requires capital improvements to comply with an MCL.

(2) A PWS affected by this rule shall comply with the monitoring frequency specified in section 12(a)(2) of this rule and meet the following requirements:

(A) If a PWS is required to conduct quarterly monitoring, the monitoring must begin in the first full calendar quarter that includes the compliance date in Table 11.

(B) If a PWS is required to conduct monitoring at a frequency that is less than quarterly, the PWS shall begin monitoring in the calendar month:

(i) recommended in the initial distribution system evaluation report prepared under:

(AA) 40 CFR 141.601, as incorporated by reference in section 10(a)(2) of this rule; or

(BB) 40 CFR 141.602, as incorporated by reference in section 10(a)(3) of this rule; or

(ii) identified in the monitoring plan developed under section 13 of this rule;

not later than twelve (12) months after the compliance date in Table 11.

(3) Compliance calculations shall be done as follows:

(A) For a PWS that is required to conduct quarterly monitoring, the PWS shall make compliance calculations according to the following:

(i) At the end of:

(AA) the fourth calendar quarter that follows the compliance date specified in Table 11; and

(BB) each subsequent calendar quarter.

(ii) Compliance calculations must be done earlier than specified under item (i) if the LRAA calculated based on fewer than four (4) quarters of data would cause the MCL to be exceeded regardless of the monitoring results of subsequent quarters.

(B) For a PWS that is required to conduct monitoring at a frequency that is less than quarterly, the PWS shall make compliance calculations beginning with the first compliance sample taken after the compliance date.

(4) For the purpose of the schedule in Table 11, the commissioner may determine that a combined distribution system does not include certain of the following systems:

(A) Consecutive systems based on factors such as receiving:

(i) water from a wholesale system only on an emergency basis; or

(ii) only a small percentage and a small volume of water from a wholesale system.

(B) Wholesale systems based on factors such as delivering:

(i) water to a consecutive system only on an emergency basis; or

(ii) only a small percentage and small volume of water to a consecutive system.

  (d) The monitoring and compliance requirements for a PWS are as follows:

(1) For a PWS required to monitor quarterly to be in compliance with the MCLs in section 2(b)(1) of this rule, the following apply:

(A) The PWS shall:

(i) calculate LRAAs for:

(AA) TTHM; and

(BB) HAA5;

using monitoring results collected under this section and sections 12 through 20 of this rule; and

(ii) determine that each LRAA does not exceed the MCL.

(B) If a PWS fails to complete four (4) consecutive quarters of monitoring, the PWS shall calculate compliance with the MCL based on the average of the available data from the most recent four (4) quarters.

(C) If a PWS takes more than one (1) sample per quarter at a monitoring location, the PWS shall average all samples taken in a quarter at that location to determine a quarterly average to be used in the LRAA calculation.

(2) For a PWS required to monitor annually or less frequently to be in compliance with the MCLs in section 2(b)(1) of this rule, the following apply:

(A) The PWS shall determine that each sample taken is less than the MCL.

(B) If any sample exceeds the MCL, the PWS shall comply with the requirements of section 16 of this rule.

(C) If no sample exceeded the MCL, the sample result for each monitoring location is considered the LRAA for that monitoring location.

  (e) A PWS is in violation of the monitoring requirements of this section and sections 12 through 20 of this rule for each quarter that a monitoring result would be used in calculating an LRAA if the PWS fails to monitor. (Water Pollution Control Division; 327 IAC 8-2.5-11; filed May 7, 2010, 9:30 a.m.: 20100602-IR-327080198FRA)