Nebraska Administrative Code
Topic - HEALTH AND HUMAN SERVICES SYSTEM
Title 179 - PUBLIC WATER SYSTEMS
Chapter 24 - STAGE 2 DISINFECTANTS AND DISINFECTION BYPRODUCTS (DBPs)
Section 179-24-004 - ROUTINE MONITORING

Universal Citation: 179 NE Admin Rules and Regs ch 24 ยง 004

Current through September 17, 2024

004.01 Monitoring

24-004.01A If a system submitted an IDSE report under 40 CFR 141 Subpart U or submits an IDSE report under 179 NAC 23, it must begin monitoring at the locations and months the system recommended in its IDSE following the schedule in 179 NAC 24-003.01, unless the Department requires other locations or additional locations after its review. If a system submitted a 40/30 certification under 40 CFR 141 Subpart U or it qualified for a very small system waiver under 40 CFR 141 Subpart U or it is a non-transient non-community water system serving <10,000 individuals, it must monitor at the location(s) and dates identified in its monitoring plan in 179 NAC 16-005.06, updated as required by 179 NAC 24-005.

24-004.01B A system must monitor at no fewer than the number of locations identified in the following table.
Source water type Population size category MonitoringFrequency1 Distributionsystemmonitoringlocation total permonitoringperiod2
Surface water and GWUDI <500 per year 2 individual
500-3,300 per quarter 2 individual
3, 301-9,999 per quarter 2 dual
10, 000-49,999 per quarter 4 dual
50, 000-249,999 per quarter 8 dual
250, 000-999,999 per quarter 12 dual
1,000, 000-4,999,999 per quarter 16 dual
>=5,000,000 per quarter 20 dual
Ground Water: <500 per year 2 individual
500-9,999 per year 2 dual
10, 000-99,999 per quarter 4 dual
100, 000-499,999 per quarter 6 dual
>=500,000 per quarter 8 dual

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.

24-004.01C If a system is an undisinfected system that begins using a disinfectant other than UV light, the system must consult with the Department to identify compliance monitoring locations for 179 NAC 24. The system must then develop a monitoring plan under 179 NAC 24-005 that includes those monitoring locations.

004.02 Monitoring Sites

24-004.02A Systems with existing data that have not conducted an IDSE must select compliance monitoring locations according to the recommendations in 179 NAC 23-008, and in consultation with the Department.

24-004.02B Systems with no existing data must select compliance monitoring locations (in consultation with the Department) by identifying sites in the distribution system with anticipated high DBP levels, using the following criteria and the protocol in 179 NAC 23-008.
1. Sites with anticipated high TTHM levels are:
a. Near the ends of the distribution system, at or before the last group of customers (particularly on smaller lines, far from major transmission lines),

b. In mixing zones where water from different sources combine within the distribution system,

c. In areas with low disinfectant residual, and

d. Downstream of storage facilities, but at or before the last group of customers.

2. Sites with anticipated high HAA5 levels are:
a. Near the ends of the distribution system, at or before the last group of customers (particularly on smaller lines, far from major transmission lines),

b. In mixing zones where water from different sources combine within the distribution system,

c. In areas with low but existing disinfectant residual, and

d. Downstream of storage facilities, but at or before the last group of customers.

24-004.02C TTHM samples sites should not be located at a dead end where there are no customers or immediately prior to booster disinfection.

24-004.02D HAA5 sample sites should not be located at a dead end where there are no customers, immediately prior to booster disinfection, where no disinfectant residual exists or in areas with biofilm problems.

004.03 After compliance monitoring data has been collected for two years (over eight consecutive quarters), the Department will evaluate the compliance monitoring data. After evaluating the data, the Department may require the system to conduct an IDSE if the system had any monitoring violations or if any individual sample exceeded 0.040 mg/L for TTHMs or 0.030 mg/L for HAA5s to determine if there is the possibility of higher distribution system DBP concentrations in areas that have not previously been monitored.

004.04 Analytical Methods

A system must use an approved method listed in 179 NAC 16-004 for TTHM and HAA5 analyses required in this chapter. Analyses must be conducted by the Department Public Health Environmental Laboratory (certified by EPA) or a laboratory that has entered into an agreement with the Department Laboratory as specified in 179 NAC 20.

Disclaimer: These regulations may not be the most recent version. Nebraska may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.