Section 179-23-008 - 179 NAC 24 COMPLIANCE MONITORING LOCATION RECOMMENDATIONS008.01 A system's IDSE report must include its recommendations and justification for where and during what month(s) TTHM and HAA5 monitoring for 179 NAC 24 should be conducted. A system must base its recommendations on the criteria in 179 NAC 23-008.02 through 23-008.05.008.02 A system must select the number of monitoring locations specified in the following table. A system must use these recommended locations and/or the sites listed in 179 NAC 24-004 as 179 NAC 24 routine compliance monitoring locations, unless the Department requires different or additional locations. A system should distribute locations throughout the distribution system to the extent possible. Source water type | Population size category | Monitoring frequency1 | Distribution system monitoring location |
Total per monitoringperiod2 | HighestTTHMlocations | HighestHAA5locations | Existing 179 NAC 16 compliance locations |
Surface water and GWUDI | <500 | per year | 2 (1 TTHM, | 1 | 1 | -- |
500-3,300 | per quarter | 1 HAA5) | 1 | 1 |
3, 301-9,999 | per quarter | 2 (1 TTHM, | 1 | 1 | -- |
10, 000-49,999 | per quarter | 1 HAA5) | 2 | 1 | 1 |
50, 000-249,999 | per quarter | 2 Dual | 3 | 3 | 2 |
250, 000-999,999 | per quarter | 4 Dual | 5 | 4 | 3 |
1,000, 000-4,999,999 | per quarter | 8 Dual 12 | 6 | 6 | 4 |
>=5,000,000 | per quarter | 16 Dual 20 Dual | 8 | 7 | 5 |
Ground water | <500 | per year | 2 (1 TTHM, | 1 | 1 | -- |
500-9,999 | per year | 1 HAA5) | 1 | 1 | -- |
10, 000-99,999 | per quarter | 2 Dual | 2 | 1 | 1 |
100, 000-499,999 | per quarter | 4 Dual 6 Dual | 3 | 2 | 1 |
>=500,000 | per quarter | 8 Dual | 3 | 3 | 2 |
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 surface water and GWUDI 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 surface water and GWUDI 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 highest TTHM and HAA5 concentrations occur at the same location, and month.
008.03 Systems must recommend 179 NAC 24 compliance monitoring locations based on standard monitoring results, system specific study results, and 179 NAC 16 or 24 compliance monitoring results. Systems must follow the protocol in 179 NAC 23-008.03A through 23-008.03H. If required to monitor at more than eight locations, a system must repeat the protocol as necessary. If the system does not have existing 179 NAC 16 or 24 compliance monitoring results or if it does not have enough existing 179 NAC 16 or 24 compliance monitoring results, it must repeat the protocol, skipping the provisions of 179 NAC 23-008.03C and 23-008.03G as necessary, until it has identified the required total number of monitoring locations. 23-008.03A Location with the highest TTHM LRAA not previously selected as a 179 NAC 24 monitoring location.23-008.03B Location with the highest HAA5 LRAA not previously selected as a 179 NAC 24 monitoring location.23-008.03C Existing 179 NAC 16 average residence time compliance monitoring location (maximum residence time compliance monitoring location for ground water systems) with the highest HAA5 LRAA not previously selected as a 179 NAC 24 monitoring location.23-008.03D Location with the highest TTHM LRAA not previously selected as a 179 NAC 24 monitoring location.23-008.03E Location with the highest TTHM LRAA not previously selected as a 179 NAC 24 monitoring location.23-008.03F Location with the highest HAA5 LRAA not previously selected as a 179 NAC 24 monitoring location.23-008.03G Existing 179 NAC 16 average residence time compliance monitoring location (maximum residence time compliance monitoring location for ground water systems) with the highest TTHM LRAA not previously selected as a 179 NAC 24 monitoring location.23-008.03H Location with the highest HAA5 LRAA not previously selected as a 179 NAC 24 monitoring location.008.04 A system may recommend locations other than those specified in 179 NAC 23-008.03 if it includes a rationale for selecting other locations. If the Department approves the alternate locations, the system must monitor at these locations to determine compliance under 179 NAC 24.008.05 A system's recommended schedule must include 179 NAC 24 monitoring during the peak historical month for TTHM and HAA5 concentration, unless the Department approves another month. Once a system has identified the peak historical month and if it is required to conduct routine monitoring at least quarterly, it must schedule 179 NAC 24 compliance monitoring at a regular frequency of every 90 days or fewer.179 Neb. Admin. Code, ch. 23, § 008