On 14 March 2023, the US EPA has come up with its new long-awaited drinking water standards to prevent water from Per- and poly fluroalkyl substances (PFAS) contamination. The new rule sets maximum contamination levels (MCLs) for six PFASs to safeguard public health. It would enforce separate standards for the almost disused PFOA and PFOS, as well as a combined limit for PFNA, PFHxS, PFBS and GenX.
In the current version of the proposed standard, MCLs separately regulate PFOA and PFOS at 4 part per trillion (ppt) which is realistic based on existing quantification and water treatment techniques. As a part of the proposal, mixtures of any of the four compounds to a hazard index of 1.0 which would indicate whether the combined amounts could pose a risk.
Water systems would need to be monitored for all six pollutants under the Safe Drinking Water Act (SDWA) regulation. Utility companies would have to inform the public and treat the water if levels were to surpass the limitations.