Contaminant Candidate List 5 (CCL 5)
On July 19, 2021, EPA published the Draft Fifth Contaminant Candidate List (CCL 5). 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 5 – Draft (July 19, 2021)
The Draft 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. EPA requested comment on the Draft CCL 5 and the process used to select the contaminants. The comment period closed on September 17, 2021.
Draft CCL 5 Summary Tables and Support Documents
- Draft CCL 5 Chemical Contaminants Table
- Draft CCL 5 Chemical Disinfection Byproducts Group Table
- Draft CCL 5 Microbial Contaminants Table
- Read the Draft CCL 5 Support Documents
Consultation with EPA's Science Advisory Board
On January 11, 2022, EPA initiated consultation meetings with the Science Advisory Board (SAB) for the Draft CCL 5. EPA will consider SAB feedback along with public comments in developing the Final CCL 5.
Previous Request for Contaminant Nominations
In developing the Draft CCL 5, EPA considered the nominations received from the public in response to the Agency’s 2018 request to identify chemicals, microbes or other potential drinking water contaminants.