Alabama Administrative Code › Title 335 - ALABAMA DEPARTMENT OF ENVIRONMENTAL MANAGEMENT › WATER DIVISION - WATER SUPPLY PROGRAM › Chapter 335-7-2 - PRIMARY DRINKING WATER STANDARDS › Section 335-7-2-.12 - Stage 2 Disinfection Byproducts

Current through Register Vol. 42, No. 9, June 28, 2024
Community and NTNC water systems that use a surface water
				  source, groundwater source or purchase water from another public water system
				  must monitor for disinfection byproducts (DBPs).
(a) Beginning January 1, 2012 systems must be
				in compliance with the TTHM and HAA5 MCLs [located in paragraph
				335-7-2-.11(a)]
				. Any site's locational running annual average that exceeds either MCL will be
				an MCL violation. Systems may be granted a compliance extension until January
				1, 2014 if the system requires capital improvements to comply with the MCLs.
				The system must enter into a binding contract, which would result in
				significant penalties to the system if the contract is not completed. All
				systems beginning January 1, 2012 must revert to routine monitoring until the
				system meets the reduced monitoring requirements below.
1. Systems must monitor during the month of
				the highest DBP concentrations.
2.
				Systems on quarterly monitoring must take dual samples sets every 90 days at
				each monitoring location.
3. The
				minimum number of samples, location of samples and sampling frequency are based
				upon the system's population and are in the following table. The sample
				locations must be at the locations identified in the system's Distribution
				System Evaluation (DSE) Report and cannot be moved without written approval
				from the Department. Systems that did not complete a DSE must monitor at the
				locations indicated in the system's monitoring plan. Systems must monitor
				according to the dates listed in the DSE Report or monitoring plan. In
				addition, surface water or ground water under the influence of surface water
				must collect one sample from the effluent of each treatment plant, prior to the
				first customer, at the same time the system conducts its DBP monitoring under
				this rule.
DBP Monitoring Frequency and Locations Beginning
				  January 1, 2012:
Source Water
								Type1
Population
Monitoring
								Frequency
Distribution System Monitoring
								Location
Total per monitoring
								period
Highest TTHM
								Locations
Highest HAA5
								Locations
Stage 1
								Locations
Surface
Water
								or
Ground
Water
Under
								the
Influence
of Surface
								Water
< 10,000
per quarter
2
1
1
10,000-49,999
per quarter
4
2
1
1
50,000-249,999
per quarter
8
3
3
2
250,000-999,999
per quarter
12
5
4
3
1,000,000- 4,999,999
per quarter
16
6
6
4
Ground
								Water
> 5,000,000
per quarter
20
8
7
5
< 500
per year
2
1
1
500-9,999
per year
2
1
1
10,000-99,999
per quarter
4
2
1
1
100,000-499,999
per quarter
6
3
2
1
> 500,000
per quarter
8
3
3
2
1 Systems that receive both surface
				  water and ground water must use the surface water section of the table to
				  determine monitoring requirements.
4. Systems may reduce monitoring to the level
				specified in the following table any time the LRAA is =0.040 mg/L for TTHM and
				=0.030 mg/L for HAA5 at all monitoring locations. Systems may only use
				monitoring data collected under this rule or rule
				335-7-2-.11 to qualify for
				reduced monitoring. In addition, the source water annual average TOC level,
				before any treatment, must be =4.0 mg/L at each treatment plant treating
				surface water or ground water under the influence of surface water.
Reduced Monitoring Frequency
Source
								Type
Population
Monitoring
								Freauency1
Distribution System Monitoring
								Location per Monitoring Period
Surface
Water
								or
Ground
Water
								Under
the
								Influence
of
								Surface
Water
< 10,000
per year
2 dual sample sets: one at the location and during
								the quarter with the highest TTHM single measurement, one at the location and
								during the quarter with the highest HAA5 single measurement
10,000-49,999
per quarter
2 dual sample sets at the locations with the
								highest TTHM and highest HAA5 LRAAs
50,000-249,999
per quarter
4 dual sample sets - at the locations with the two
								highest TTHM and two highest HAA5 LRAAs
250,000-999,999
Per quarter
6 dual sample sets - at the locations with the
								three highest TTHM and three highest HAA5 LRAAs
1,000,000-4,999,99 9
Per quarter
8 dual sample sets - at the locations with the four
								highest TTHM and four highest HAA5 LRAAs
>5,000,000
Per quarter
10 dual sample sets - at the locations with the
								five highest TTHM and five highest HAA5 LRAAs
Ground
								Water
< 500
every third year
1 TTHM and 1 HAA5 sample: one at the location and
								during the quarter with the highest TTHM single measurement, one at the
								location and during the quarter with the highest HAA5 single measurement; 1
								dual sample set per year if the highest TTHM and HAA5 measurements occurred at
								the same location and quarter.
500-9,999
per year
1 TTHM and 1 HAA5 sample: one at the location and
								during the quarter with the highest TTHM single measurement, one at the
								location and during the quarter with the highest HAA5 single measurement; 1
								dual sample set per year if the highest TTHM and HAA5 measurements occurred at
								the same location and quarter
10,000-99,999
per year
2 dual sample sets: one at the location and during
								the quarter with the highest TTHM single measurement, one at the location and
								during the quarter with the highest HAA5 single measurement
100,000-499,999
per quarter
2 dual sample sets; at the locations with the
								highest TTHM and highest HAA5 LRAAs
>500,000
per quarter
4 dual sample sets at the locations with the two
								highest TTHM and two highest HAA5 LRAAs
1 Systems on quarterly monitoring must
				  take dual sample sets every 90 days.
5. Systems may remain on reduced monitoring
				as long as the TTHM LRAA is =0.040 mg/L and the HAA5 LRAA is =0.030 mg/L at
				each monitoring location for systems on quarterly reduced monitoring or each
				TTHM sample is =0.060 mg/L and each HAA5 LRAA is =0.045 mg/L for systems with
				annual or less frequent monitoring. In addition, the source water annual
				average TOC level, before any treatment must be =4.0 mg/L at each treatment
				plant treating surface water or ground water under the influence of surface
				water. Systems must return to routine monitoring if any of the levels are
				exceeded. The Department may return any system to routine monitoring at its
				discretion.
6. The following TOC
				monitoring requirements apply to systems qualifying for or on reduced TTHM and
				HAA5 monitoring. If a system is required to monitor for TOC per subparagraph
				335-7-2-.11(i)8.,
				monthly samples shall be taken every 30 days.
7. If a system is required to monitor
				annually or less the system must increase monitoring to dual samples sets once
				per quarter (taken every 90 days) at all locations if a TTHM sample is
				>0.080 mg/L or a HAA5 sample is >0.060 mg/L at any location. A system is
				in violation of the MCL when the LRAA exceeds the MCLs based upon four
				consecutive quarters of monitoring or the LRAA calculated based on fewer than
				four quarters of data if the MCL would be exceeded regardless of the monitoring
				results of subsequent quarters. Systems may return to routine monitoring once
				the systems has conducted increased monitoring for at least four consecutive
				quarters and the LRAA for every monitoring location is =0.060 mg/L for TTHM and
				is =0.045 mg/L for HAA5.
8. If a
				system fails to collect any required sample, the system has incurred a
				monitoring violation. The system will receive a monitoring violation for each
				quarter in which the missed monitoring result would have been used to determine
				compliance.
9. Systems on increased
				monitoring under rule
				335-7-2-.11 must remain on
				increased monitoring until the system meets the requirements of this rule for
				returning to routine monitoring.
10. Systems that are required to monitor
				quarterly must calculate LRAAs for TTHM and HAA5 using monitoring results
				collected under this rule and determine that each LRAA does not exceed the MCL.
				If the system does not collect four consecutive quarters of monitoring, the
				system must calculate compliance with the MCL based on the average of the
				available data from the most recent four quarters. If the system takes more
				than one sample per quarter at a monitoring location, they must average all
				samples taken in the quarter at that location to determine a quarterly average
				to be used in the LRAA calculation.
11. Systems that are required to monitor
				yearly or less frequently must determine that each sample taken is less than
				the MCL. If no sample exceeds the MCL, the sample result is considered the LRAA
				and the system is in compliance. If any sample exceeds the MCL the system is
				not in violation but must begin increased monitoring as outlined in this
				rule.
12. A system that is required
				to conduct quarterly monitoring must make compliance calculations at the end of
				the fourth quarter that follows the compliance date and at the end of each
				subsequent quarter or earlier if the LRAA calculated based on fewer than four
				quarters of data would cause the MCL to be exceeded regardless of the
				monitoring results of subsequent quarters.
(i)
				Systems that monitor less frequently than quarterly must determine compliance
				beginning with the first compliance sample taken after the compliance
				date.
(ii) Upon exceeding the MCL,
				the system will be required to submit a schedule to either establish a
				treatment process using the EPA approved best available technology to achieve
				compliance with the MCL or cease using the source of supply in conjunction with
				a Department issued compliance schedule.
13. Systems that did not complete a DSE must
				develop and implement a monitoring plan for TTHMs and HAA5s. The monitoring
				plan must be submitted to the Department by the applicable date in rule
				335-7-2-.13. Systems must
				identify and justify all monitoring locations.