Section 179-23-004 - STANDARD MONITORING004.01 Standard Monitoring Plan A system's standard monitoring plan must comply with 179 NAC 23-004.01A through 23-004.01D. The system must prepare and submit its standard monitoring plan to the Department according to the time frame in 179 NAC 23-003.01.
23-004.01A A system's standard monitoring plan must include a schematic of the system's distribution system (including distribution system entry points and their sources, and storage facilities), with notes indicating locations and dates of all projected standard monitoring, and all projected compliance monitoring.23-004.01B A system's standard monitoring plan must include justification of standard monitoring location selection and a summary of data the system relied on to justify standard monitoring location selection.23-004.01C A system's standard monitoring plan must specify the population served and system type: surface water/GWUDI, or ground water.23-004.01D A system must retain a complete copy of its standard monitoring plan including any Department modification of the system's standard monitoring plan, for as long as the system is required to retain its IDSE.004.02 Standard Monitoring 23-004.02A A system must monitor as indicated in the following table. A system must collect dual sample sets at each monitoring location. One sample in the dual sample set must be analyzed for TTHMs. The other sample in the dual sample set must be analyzed for HAA5. A system must conduct one monitoring period during the peak historical month for TTHM levels or HAA5 levels or the month of warmest water temperature. A system must review available compliance, study, or operational data to determine the peak historical month for TTHM or HAA5 levels or warmest water temperature. | Source water type | Population size category | Monitoring periods and frequency of sampling | Distribution system monitoring locations1 |
| Total per monitoring period | Near entry points | Average residence time | High TTHM locations | High HAA5 locations |
| Surface water and ground water under the direct influence of surface water | <500 consecutive systems | One (during peak historical month)2 | 2 | 1 | 1 |
| <500 non-consecutive systems | One (during peak historical month)2 | 2 | 1 | 1 |
| 500-3,300 consecutive systems | Four (every 90 days) | 2 | 1 | 1 |
| 500-3,300 non-consecutive systems | Four (every 90 days) | 2 | 1 | 1 |
| 3,301 - 9,999 | Four (every 90 days) | 4 | 1 | 2 | 1 |
| 10, 000-49,999 | Six (every 60 days) | 8 | 1 | 2 | 3 | 2 |
| 50, 000-249,999 | Six (every 60 days) | 16 | 3 | 4 | 5 | 4 |
| 250, 000-999,999 | Six (every 60 days) | 24 | 4 | 6 | 8 | 6 |
| 1,000, 000-4,999,999 | Six (every 60 days) | 32 | 6 | 8 | 10 | 8 |
| >=5,000,000 | Six (every 60 days) | 40 | 8 | 10 | 12 | 10 |
| Ground Water | <500 consecutive systems | One (during peak historical month)2 | 2 | 1 | 1 |
| <500 non-consecutive systems | One (during peak historical month)2 | 2 | 1 | 1 |
| 500-9,999 | Four (every 90 days) | 2 | 1 | 1 |
| 10, 000-99,999 | Four (every 90 days) | 6 | 1 | 1 | 2 | 2 |
| 100, 000-499,999 | Four (every 90 days) | 8 | 1 | 1 | 3 | 3 |
| >=500,000 | Four (every 90 days) | 12 | 2 | 2 | 4 | 4 |
1 A dual sample set (i.e., a TTHM and an HAA5 sample) must be taken at each monitoring location during each monitoring period.
2 The peak historical month is the month with the highest TTHM or HAA5 levels or the warmest water temperature.
23-004.02B Systems must take samples at locations other than the existing 179 NAC 16 or 24 monitoring locations. Monitoring locations must be distributed throughout the distribution system.23-004.02C If the number of entry points to the distribution system is fewer than the specified number of entry point monitoring locations, excess entry point samples must be replaced equally at high TTHM and HAA5 locations. If there is an odd extra location number, systems must take a sample at a high TTHM location. If the number of entry points to the distribution system is more than the specified number of entry point monitoring locations, the system must take samples at entry points to the distribution system having the highest annual water flows.23-004.02D Standard monitoring may not be reduced.004.03 IDSE Report IDSE reports must include the elements required in 179 NAC 23-004.03A through 23-004.03D. IDSE reports must be submitted to the Department according to the time frame in 179 NAC 23-003.01.
23-004.03A An IDSE report must include all TTHM and HAA5 analytical results from 179 NAC 16 or 24 compliance monitoring and all standard monitoring conducted during the period of the IDSE as individual analytical results and locational running annual averages (LRAAs) presented in a tabular or spreadsheet format acceptable to the Department. If changed from the standard monitoring plan submitted under 179 NAC 23-004.01, the report must also include a schematic of the distribution system, the population served, and system type: surface water/GWUDI or ground water.23-004.03B The IDSE report must include an explanation of any deviations from the system's approved standard monitoring plan.23-004.03C A system must recommend and justify 179 NAC 24 compliance monitoring locations and timing based on the protocol in 179 NAC 23-008.23-004.03D A system must retain a complete copy of its IDSE report submitted under 179 NAC 23-004 or 40 CFR 141 Subpart U for 10 years after the date that the report was submitted. If the Department modifies the 179 NAC 24 monitoring requirements that a system recommended in its IDSE report or if the Department approves alternative monitoring locations, the system must keep a copy of the Department's notification on file for 10 years after the date of the Department's notification. Systems must make the IDSE report and any Department notification available for review by the Department or the public.179 Neb. Admin. Code, ch. 23, § 004