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).
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.
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.
Ala. Admin. Code r. 335-7-2-.12
Author: Dennis D. Harrison
Statutory Authority:Code of Ala. 1975, §§ 22-23-33, 22-23-49, 22-22A-5, 22-22A-6.