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Contaminant Candidate List (CCL) and Regulatory Determination
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Contaminant Candidate List 5 - CCL 5

The Contaminant Candidate List (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). 

With the announcement of the Draft CCL 5 on July 19, 2021, EPA provided a period for public comment and consulted with EPA’s Science Advisory Board (SAB). Following minor revisions to address public comments and SAB’s review, EPA published the Final CCL 5 on November 14, 2022. 

Federal Register Notices

  • Federal Register Notice: Drinking Water Contaminant Candidate List 5 - Final (November 14, 2022)

  • Federal Register Notice: Drinking Water Contaminant Candidate List 5 – Draft (July 19, 2021) 

Read More About CCL 5

  • Overview of the CCL 5 Approach 

  • CCL 5 Technical Support Documents

  • CCL 5 Frequent Questions

  • Fact Sheet: Fifth Contaminant Candidate List (CCL 5) (pdf) (141.91 KB, October 2022, EPA 815-F-22-005)

  • Additional information is available in the docket folder EPA-HQ-OW-2018-0594 at regulations.gov.

CCL 5 Contaminants

The CCL 5 includes 66 chemicals, three chemical groups (per- and polyfluoroalkyl substances (PFAS), cyanotoxins, and disinfection byproducts (DBPs)), and 12 microbes, which were selected from a universe of chemicals used in commerce, pesticides, biological toxins, disinfection byproducts, and waterborne pathogens. Tables for the CCL 5 contaminants are provided below.

  • CCL 5 Chemical Contaminants List
Back photo is a microscopic image of Legionella (CDC) and the front image is an agar plate with Legionella growth (EPA)
  • CCL 5 Microbial Contaminants List
  • CCL and Regulatory Determination Home
  • Basic Information
  • Draft CCL 6
  • CCL 5
  • CCL 4
  • CCL 3
  • CCL 2
  • CCL 1
  • Regulatory Determination 4
  • Regulatory Determination 3
  • Regulatory Determination 2
  • Regulatory Determination 1
  • Types of Drinking Water Contaminants
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on November 14, 2022
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