In July 2021 the Environmental Protection Agency (EPA) published the draft fifth Contaminant Candidate List (CCL5) for public review and comment. On October 28, 2022 EPA signed off on the final CCL5. EPA posted a pre-Federal Register publication copy of the final CCL5.
The “CCL 5 includes 66 chemicals, 3 chemical groups (cyanotoxins, disinfection byproducts (DBPs), and per- and polyfluoroalkyl substances (PFAS), and 12 microbial contaminants.”
The CCL5 list of chemicals begins on page 15 of the enclosed. The list of chemical groups begins on page 18, and the list of microbials is on page 19.
EPA CCL5 webpage:
Within 18 months of enactment of the 1996 Safe Drinking Water Act Amendments, and then every five years thereafter, EPA is required to propose and finalize a CCL. Constituents are included on the CCL that “…are not subject to any proposed or promulgated national primary drinking water regulation, which are known or anticipated to occur in public water systems, and which may require regulation….” After publication of the CCL, EPA then goes through a review process (referred to as a Regulatory Determination) and makes an assessment as to whether a drinking water regulation should be promulgated for at least five of the constituents on the CCL.