Section 327IAC8-2.5-12. Routine monitoring; stage 2 disinfection byproducts requirements

   (a) The following are the routine monitoring requirements for a PWS to comply with section 11 of this rule, this section, and sections 13 through 20 of this rule:

(1) A PWS shall comply with monitoring location and schedule requirements as follows:

(A) If a PWS submitted an initial distribution system evaluation (IDSE) report as required under section 10 of this rule, the PWS shall:

(i) begin monitoring at the locations and months:

(AA) recommended in the IDSE report submitted under 40 CFR 141.605, as incorporated by reference in section 10(a)(6) of this rule; and

(BB) following the schedule in section 11(c) of this rule; or

(ii) monitor according to the directive of the:

(AA) commissioner; or

(BB) EPA;

if either requires other locations or additional locations after review of the PWS's IDSE report.

(B) A PWS shall monitor at the location or locations and dates identified in the monitoring plan submitted in accordance with section 6(f) of this rule and updated as required by section 13 of this rule if the PWS meets one (1) of the following:

(i) The PWS submitted a 40/30 certification under 40 CFR 141.603, as incorporated by reference in section 10(a)(4) of this rule.

(ii) The PWS qualified for a very small system waiver under 40 CFR 141.604, as incorporated by reference in section 10(a)(5) of this rule.

(iii) The PWS is an NTNCWS serving fewer than ten thousand (10,000) people.

(2) A PWS shall monitor at not fewer than the number of locations identified in the following table:

Table 12
Source Water Type	Population Size Category	Monitoring Frequency1	Distribution System Monitoring Locations Total per Monitoring Period2
Subpart H	< 500	per year	2
	500-3,300	per quarter	2
	3,301-9,999	per quarter	2
	10,000-49,999	per quarter	4
	50,000-249,999	per quarter	8
	250,000-999,999	per quarter	12
	1,000,000-4,999,999	per quarter	16
	≥ 5,000,000	per quarter	20
Ground water	< 500	per year	2
	500-9,999	per year	2
	10,000-99,999	per quarter	4
	100,000-499,999	per quarter	6
	≥ 500,000	per quarter	8
1 All systems must monitor during month of highest DBP concentrations.
2 Systems on quarterly monitoring must take dual sample sets every 90 days at each monitoring location, except for Subpart H systems serving 500-3,300. Ground water systems serving 500-9,999 on annual monitoring must take dual sample sets at each monitoring location. All other systems on annual monitoring and Subpart H systems serving 500-3,300 are required to take individual TTHM and HAA5 samples (instead of a dual sample set) at the locations with the highest TTHM and HAA5 concentrations, respectively. For systems serving fewer than 500 people, only one location with a dual sample set per monitoring period is needed if the highest TTHM and HAA5 concentrations occur at the same location and month.

(3) If an undisinfected PWS begins using a disinfectant other than UV light after the dates according to 40 CFR 141.600 through 40 CFR 141.605, as incorporated in section 10(a)(6) of this rule, for complying with the IDSE requirements, the PWS shall do the following:

(A) Consult with the commissioner to identify compliance monitoring locations for section 11 of this rule, this section, and sections 13 through 20 of this rule.

(B) Develop a monitoring plan under section 13 of this rule that includes the monitoring locations identified under clause (A).

  (b) A PWS shall use analytical methods approved under section 5 of this rule for TTHM and HAA5 analyses in section 11 of this rule, this section, and sections 13 through 20 of this rule. Analyses must be conducted by laboratories that have received certification by EPA or the commissioner as specified in section 5 of this rule. (Water Pollution Control Division; 327 IAC 8-2.5-12; filed May 7, 2010, 9:30 a.m.: 20100602-IR-327080198FRA; filed Feb 25, 2013, 8:36 a.m.: 20130327-IR-327110667FRA)