Microbial/Disinfection Byproducts Rules Updates

By Robert Hollander, P.E.

As a result of findings from the Third Six-Year Review of National Primary Drinking Water Regulations (NPDWR), as required under the Safe Drinking Water Act, subsequent litigation (i.e. 2020 Waterkeepers Alliance v EPA settlement agreement), and informed by additional data and information from the 4th Six Year Review (evaluation currently underway) the U.S. Environmental Protection Agency has initiated an effort to review microbial and disinfection byproduct rules with the intent of finding opportunities for better public health protection and publish a notice of final rulemaking by September 30, 2027.

Rules reviewed by EPA

The review includes requirements in the following rules:

• Surface Water Treatment Rule, 1989 (54 FR 27486)
• Interim Enhanced Surface Water Treatment Rule, 1998 (63 FR 69478)
• Stage 1 Disinfectants and Disinfection Byproducts Rule, 1998 (63 FR 69390)
• Long-Term 1 Enhanced Surface Water Treatment Rule, 2002 (67 FR 1812)
• Stage 2 Disinfectants and Disinfection Byproducts Rule, 2006 (71 FR 388)

Five Topic Areas

EPA conducted a series of meetings in 2021 to review topics to be addressed in the review, informed by a series of issue papers. Five topic areas were identified. These are as follows:

• Disinfectant Residual Levels and Opportunistic Pathogens (including Legionella)
• Regulated and Unregulated Disinfection Byproducts and Consecutive Drinking Water Systems
• Distribution System Issues/Tools and Finished Drinking Water Storage
• Source Water Protection Considerations and Precursor Treatment/Removal
• Sanitary Surveys and Water Safety Plans

Upon completion of the stakeholder meetings EPA requested that the National Drinking Water Advisory Council (NDWAC) provide recommendations to EPA on potential improvements to the MDBP rules. In addition, EPA also requested the NDWAC to convene a Microbial and Disinfection Byproducts Rule Revision Working Group (MDBP Rule Revisions WG) that will develop specific recommendations for the NDWAC to consider.

EPA Consensus Recommendation Topics

EPA is seeking consensus recommendations, where possible, on the following topics:

• Disinfectant residuals and opportunistic pathogens
• Regulated and unregulated DBPs
• Finished water storage facilities
• Distribution system water quality management
• Source water approach, including DBP precursor removal
• Mischaracterized ground water under the direct influence of surface water (GWUDI) systems
• Sanitary Surveys
• Water Safety Plans
• Consecutive and small systems

There will an emphasis on environmental justice and concerns of and impacts to disadvantaged and historically underserved communities as part of the process.

How will this affect SAMS?

The MDBP Rule Revisions WG held their first meeting on May 23, 2022. It is anticipated meetings will continue into the middle of 2023. We will keep you updated on discussion topics and potential future regulatory developments.
NJBSoft is watching these developments and will update SAMS compliance databases to meet client needs when they are final and become effective.


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