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  2. Six-Year Review of Drinking Water Standards

Public Engagements: Potential Revisions of the Microbial and Disinfection Byproducts Rules

EPA is currently seeking public input and information to inform potential regulatory revisions of eight National Primary Drinking Water Regulations (NPDWRs) included in Microbial and Disinfection Byproducts (MDBP) rules following the Six-Year Review 3.

EPA hosted an initial two-day virtual public meeting in October 2020 to solicit input on further improving public health protection from MDBPs in drinking water. Throughout 2021, EPA also sought input relevant to any potential rule revisions through a series of public meetings focusing on specific topics identified through public comments and information.

Following the public meetings, EPA is continuing to provide the public with an opportunity to send written input to EPA in the public docket at www.regulations.gov Docket ID: EPA-HQ-OW-2020-0486. EPA will consider the data and/or information provided at the previous meetings, comments submitted to the docket, comments on the Six-Year Review 3 Federal Register notice, and information gathered at other future stakeholder engagements in its determination on how to proceed with any potential rule revisions.

Additional questions or comments about the public engagements can be submitted to MDBPRevisions@epa.gov.


Public Engagement Information

National Drinking Water Advisory Council

EPA provided a charge to the National Drinking Water Advisory Council (NDWAC), a Federal Advisory Committee (FAC) established under the Safe Drinking Water Act, to provide the agency with advice and recommendations on key issues related to potential revisions to MDBP rules. To support the work of the NDWAC, EPA asked the Council to form a working group that includes individuals with a variety of backgrounds and expertise.  Learn more about and the NDWAC Letter to the Administrator on Potential Revisions to MDBP Rules and the MDBP Rule Revisions Working Group.

2021 Public Meeting Series Information

  • May 20, 2021: Disinfectant Residual Levels and Opportunistic Pathogens (including Legionella)
    • Meeting materials and summary for the May meeting are posted to the public docket at www.regulations.gov Docket ID: EPA-HQ-OW-2020-0486.
    • Final May Meeting Agenda 
  • June 24, 2021: Regulated and Unregulated Disinfection Byproducts and Consecutive Drinking Water Systems
    • Meeting materials and summary for the June meeting are posted to the public docket.
    • Final June Meeting Agenda
  • July 15, 2021: Distribution System Issues/Tools and Finished Drinking Water Storage
    • Meeting materials and summary for the July meeting are posted to the public docket.
    • Final July Meeting Agenda
  • August 10, 2021: Source Water Protection Considerations and Precursor Treatment/Removal
    • Meeting materials and summary for the August meeting are posted to the public docket.
    • Final August Meeting Agenda
  • September 29, 2021: Sanitary Surveys and Water Safety Plans
    • Meeting materials and summary for the September meeting are posted to the public docket.
    • Final September Meeting Agenda
  • November 18, 2021: Meeting Series Summary
    • Meeting materials for the November meeting are posted to the public docket.
    • Final November Meeting Agenda

October 2020 Meeting Information

  • Final Meeting Agenda
  • Federal Register Notice: Microbial and Disinfection Byproducts Rules: Public Meeting to Inform Potential Rule Revisions
  • Meeting materials can be found in the public docket.

Six-Year Review of Drinking Water Standards

  • Statutory Requirements
  • Learn About Six-Year Review Elements
  • Six-Year Review 4
  • Six-Year Review 3
  • Six-Year Review 2
  • Six-Year Review 1
Contact Us About the Six Year Review of Drinking Water Standards
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on February 24, 2025
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