On April 6, 2026, EPA published a request for comments on its draft Sixth Contaminant Candidate List (CCL 6).

CCL 6 is a draft list of contaminants that are currently not subject to proposed or promulgated national primary drinking water regulations (NPDWRs), which are applicable to public water systems under the Safe Drinking Water Act (SDWA), and are being considered for regulation under the SDWA. In particular, CCL 6 includes:

• Seventy-five chemicals;

• Four chemical groups (disinfection byproducts (DBPs), microplastics, per- and polyfluoroalkyl substances (PFAS), and pharmaceuticals); and

• Nine microbes.

Regarding PFAS, EPA is proposing regulation of all PFAS, excluding those that are already subject to NPDWRs at the time the final CCL 6 is published, that meet the structural definition of PFAS that was also used in CCL 5. That structural definition of PFAS includes chemicals that contain at least one of the following three structures:

(1) R-(CF2)-CF(R′)R′′, where both the CF2 and CF moieties are saturated carbons, and none of the R groups can be hydrogen;

(2) R-CF2OCF2-R′, where both the CF2 moieties are saturated carbons, and none of the R groups can be hydrogen; and

(3) CF3C(CF3)RR′, where all the carbons are saturated, and none of the R groups can be hydrogen.

EPA’s request for comments can be found here, and the public comment must be received by June 5, 2026.