(a) Monitoring. (1) If you submitted an IDSE report, you must begin monitoring at the locations and months you have recommended in your IDSE report submitted under Sec. 141.605 following the schedule in Sec. 141.620(c), unless the State requires other locations or additional locations after its review. If you submitted a 40/30 certification under Sec. 141.603 or you qualified for a very small system waiver under Sec. 141.604 or you are a nontransient noncommunity water system serving <10,000, you must monitor at the location(s) and dates identified in your monitoring plan in Sec. 141.132(f), updated as required by Sec. 141.622.
(1) If you submitted an IDSE report, you must begin monitoring at the locations and months you have recommended in your IDSE report submitted under Sec. 141.605 following the schedule in Sec. 141.620(c), unless the State requires other locations or additional locations after its review. If you submitted a 40/30 certification under Sec. 141.603 or you qualified for a very small system waiver under Sec. 141.604 or you are a nontransient noncommunity water system serving <10,000, you must monitor at the location(s) and dates identified in your monitoring plan in Sec. 141.132(f), updated as required by Sec. 141.622.
(2) You must monitor at no fewer than the number of locations identified in this paragraph (a)(2). ----------------------------------------------------------------------------------------------------------------
Distribution
system
monitoring
Source water type Population size category Monitoring Frequency \1\ location total
per monitoring
period \2\----------------------------------------------------------------------------------------------------------------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............... 20Ground 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 you are an undisinfected system that begins using a disinfectant other than UV light after the dates in subpart U of this part for complying with the Initial Distribution System Evaluation requirements, you must consult with the State to identify compliance monitoring locations for this subpart. You must then develop a monitoring plan under Sec. 141.622 that includes those monitoring locations.
(b) Analytical methods. You must use an approved method listed in Sec. 141.131 for TTHM and HAA5 analyses in this subpart. Analyses must be conducted by laboratories that have received certification by EPA or the State as specified in Sec. 141.131. [71 FR 488, Jan. 4, 2006, as amended at 74 FR 30958, June 29, 2009]