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  2. Contaminant Candidate List (CCL) and Regulatory Determination

Draft Contaminant Candidate List 6 - CCL 6

Announcement of the Draft CCL 6 

On April 02, 2026, EPA announced the draft Sixth Contaminant Candidate List (CCL 6). The CCL is a list of contaminants that are currently not subject to any proposed or promulgated national primary drinking water regulations but are known or anticipated to occur in public water systems. Contaminants listed on the CCL may require future regulation under the Safe Drinking Water Act (SDWA).

  • Federal Register Notice: Drinking Water Contaminant Candidate List 6 - Draft (April 06, 2026)
  • Additional information is available in the docket folder EPA-HQ-OW-2022-0946 at regulations.gov.

The draft CCL 6 includes 75 chemicals, 4 chemical groups (microplastics, pharmaceuticals, per- and polyfluoroalkyl substances (PFAS), and disinfection byproducts (DBPs), and 9 microbes. EPA is seeking comment on the draft CCL 6 and the process used to select the contaminants. Instructions on how to submit comments are included in the Federal Register notice.  Comments must be received on or before June 05, 2026.

Draft CCL 6 Support Documents and Additional Information

  • Overview of the CCL 6 Approach 
  • CCL 6 Frequent Questions
  • Draft CCL 6 Technical Support Documents
  • 2026 Human Health Benchmarks for Pharmaceuticals (HHB-Rx)

Close up of water molecules

Draft CCL 6 Chemicals

  • Chemical Contaminants List
Magnified image of a microbial drinking water contaminant

Draft CCL 6 Microbes

  • Microbial Contaminants List

Previous Request for Contaminant Nominations 

In developing the draft CCL 6, the EPA considered the nominations received from the public in response to the Agency's 2023 request to identify chemicals, microbes or other potential drinking water contaminants.

  • Federal Register Notice: Drinking Water Contaminant Candidate List 6 - Nominations (February 17, 2023) 

Contaminant Candidate List (CCL) and Regulatory Determination

  • Basic Information
  • Contaminant Candidate List 6
  • Contaminant Candidate List 5
  • Contaminant Candidate List 4
  • Contaminant Candidate List 3
  • Contaminant Candidate List 2
  • Contaminant Candidate List 1
  • Regulatory Determination 5
  • Regulatory Determination 4
  • Regulatory Determination 3
  • Regulatory Determination 2
  • Regulatory Determination 1
  • Types of Drinking Water Contaminants
Contact Us About the CCL and Regulatory Determinations
Contact Us About the CCL and Regulatory Determinations to ask a question, provide feedback, or report a problem.
Last updated on April 7, 2026
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