Compliance with Stage 2 DBPR
All systems subject to the Stage 2 DBPR must develop a Compliance Monitoring Plan. This plan will identify how systems intend to sample for compliance with the Stage 2 DBPR.
Systems must prepare a plan prior to the date they are required to begin their Stage 2 DBPR compliance monitoring and must keep their plan on file for state and public review.
Surface water and GWUDI systems (and their purchasers) with populations over 3,300 must submit their compliance monitoring plans for review and approval prior to beginning compliance monitoring.
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Stage 2 Compliance Monitoring Plan Requirements
The Compliance Monitoring Plan must include the following information:
- Monitoring locations
- Monitoring dates
- Compliance calculation procedures
Systems that Submitted an IDSE Report
Systems that conducted IDSE standard monitoring or a system specific study included the first two items, (monitoring locations and monitoring dates) in their IDSE Report. If these systems also included their compliance calculation procedures in their IDSE Report, then their IDSE Report can serve as their Compliance Monitoring Plan, and they will not need to submit a separate plan.
Systems that Did Not Submit an IDSE Report
Systems that received a Very Small Systems Waiver or a 40/30 Certification, and Non-transient Non-community systems were not required to submit an IDSE Report, and therefore they must prepare a Compliance Monitoring Plan.
In their Compliance Monitoring Plan, these systems must select their Stage 2 DBPR monitoring locations and dates and must discuss the compliance calculation procedures. Some of these systems can comply by updating their Stage 1 DBPR monitoring plan (i.e., identify additional locations for compliance monitoring by alternating locations with high TTHM and HAA5 levels until the required number of locations has been identified).
If a system has more Stage 1 DBPR sites than the number required for Stage 2 DBPR compliance monitoring, they must select sites by alternating between locations representing high TTHM and high HAA5 levels until the required number of Stage 2 DBPR compliance monitoring locations have been identified.
Use this worksheet to help you organize your Stage 1 data.
If a system has fewer Stage 1 DBPR sites than the number required by the Stage 2 DBPR, the system must begin by using the existing Stage 1 DBPR sites. They then must select additional locations by identifying sites in the distribution system with anticipated high DBP levels, alternating selection of locations representing high TTHM and high HAA5 levels,
starting with high TTHM. The system must include the rationale for identifying locations as having high levels of TTHM and HAA5 in their plan.
Get guidance on how to select high TTHM and high HAA5 sites in the absence of existing monitoring data.
Changes to a Monitoring Plan
If a system makes any changes in treatment, distribution system operations and layout, or other factors that may affect TTHM or HAA5 formation, these changes may warrant a modification to their monitoring locations. In this case the system must revise their Compliance Monitoring Plan. The system must consult with the State regarding the need for the changes and the most appropriate modifications. The revised sites must replace existing compliance monitoring locations with expected high TTHM or HAA5 levels.
Modifications to the Compliance Monitoring Plan may be initiated by the system, or the State may require the modifications. If the State becomes aware of major system changes (in the process of review of plans and specifications or during technical assistance, water system survey, or other system site visit), the State will consider if these system changes have a likelihood of affecting relative DBP levels in the distribution system.Systems changes that may warrant modifications to a system's monitoring plan may include:
- Adding or removing a source
- Adding or removing a booster chlorination site
- Adding or removing a storage tank
- Adding a new service area
- Changes to the primary or residual disinfectant site or type (but only if the change is expected to impact relative DBP levels in the distribution system).