On March 3, 2021, the Environmental Protection Agency (EPA) published the Fourth Regulatory Determinations in Federal Register, including a determination to regulate perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) in drinking water. Per the Safe Drinking Water Act, following publication of the Regulatory Determination, the Administrator shall propose a maximum contaminant level goal (MCLG) and a national primary drinking water regulation (NPDWR) not later than 24 months after determination and promulgate a NPDWR within 18 months after proposal (the statute authorizes a 9-month extension of this promulgation date). With this action, EPA intends to develop a proposed national primary drinking water regulation for PFOA and PFOS, and as appropriate, take final action. Additionally, EPA will continue to consider other PFAS as part of this action. This action provides a key commitment in EPA's 'PFAS Strategic Roadmap: EPA's Commitments to Action 2021-2024.