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. 

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.
Back photo is a microscopic image of Legionella (CDC) and the front image is an agar plate with Legionella growth (EPA)

Contaminant Candidate List (CCL) and Regulatory Determination

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Last updated on January 4, 2024