text: An estimated 26,000 U.S. sites are contaminated with PFASs. At least six million Americans are estimated to have drinking water containing PFASs above the safe limit published prior to 2022 by the U.S. Environmental Protection Agency (EPA). More than 200 million Americans are estimated to live in places where the tap water PFAS level (a combination of PFOA and PFOS levels) exceeds the 1 ppt (part per trillion) limit set in 2022 by the EPA.
  , the states of California, Connecticut, Massachusetts, Michigan, Minnesota, New Hampshire, New Jersey, New York, Vermont, and Wisconsin had enforceable drinking water standards for between two and six types of PFAS. The six chemicals (termed by the Massachusetts Department of Environmental Protection as PFAS6) are measured either individually or summed as a group depending on the standard; they are:
  * Perfluorooctanesulfonic acid (PFOS)
  * Perfluorooctanoic acid (PFOA)
  * Perfluorohexanesulfonic acid (PFHxS)
  * Perfluorononanoic acid (PFNA)
  * Perfluoroheptanoic acid (PFHpA)
  * Perfluorodecanoic acid (PFDA)
  EPA published non-enforceable drinking water health advisories for PFOA and PFOS in 2016. In March 2021 EPA announced that it would develop national drinking water standards for PFOA and PFOS. On December 27, 2021, EPA published a regulation requiring drinking water utilities to conduct monitoring for 29 compounds. The data are to be collected during 2023 to 2025. EPA will pay for the monitoring costs for small drinking water systems (those serving a population of 10,000 or fewer). The agency may use the monitoring data to develop additional regulations.
  In mid-2021 EPA announced plans to revise federal wastewater regulations (effluent guidelines) for several industries that manufacture PFASs or use PFASs in fabricating various products.
  In October 2021 EPA announced the PFAS Strategic Roadmap. It is a "whole-of-EPA" strategy and considers the full lifecycle of PFAS—including drinking water monitoring and risk assessment for PFOA and PFOS in biosolids (processed wastewater sludge used as fertilizer).
  The EPA issued health advisories for four specific PFASs in June 2022, significantly lowering their safe threshold levels for drinking water. PFOA was reduced from 70 ppt to 0.004 ppt, while PFOS was reduced from 70 ppt to 0.02 ppt. GenX's safe levels were set at 10 ppt, while PFBS were set to 2000 ppt. While not enforceable, these health advisories are intended to be acted on by states in setting their own drinking water standards.
  A formal EPA rule to add PFOA and PFAS as hazardous chemicals was first issued for comment in August 2022, which would require anyone discharging waste to monitor and restrict the release of these PFAS to set levels, and report when the wastewater exceeds it. It would also make grounds affected by high levels of PFIA or PFAS to be considered Superfund cleanup sites. The EPA formally established rules for these two chemicals.
  EPA has listed recommended steps that consumers may take to reduce possible exposure to PFAS chemicals.
  On 14 March 2023, EPA announced the proposed National Primary Drinking Water Regulation (NPDWR). This proposal includes new maximum contaminant levels (MCLs) in drinking water for six well-known PFAS: PFOA, PFOS, GenX, PFBS, PFNA, and PFHxS. While the proposal does not require any actions until its finalization, the EPA believes it will be implemented by late 2023. If these new restrictions are put into place, the EPA expects that they will prevent thousands of deaths and tens of thousands of PFAS-attributable illnesses. Along with legally enforceable MCLs, the EPA proposal will also require public water systems to actively monitor for the 6 PFAS, notify the public about the level of PFAS in the water supply, and take measures to reduce the level of PFAS in drinking water if they exceed the MCLs.
  Between 2016 and 2021 the U.S. Geological Survey (USGS) tested tap water from 716 locations across the United States, and reported in 2023 that the PFAS levels exceeded the EPA advisories in approximately 75% of the samples from urban areas and in approximately 25% of the rural area samples.
  In 2023, the American multinational 3M reached a US$10.3 billion settlement with a host of US public water systems to resolve water pollution claims tied to PFAS. Three other major chemicals companies – Chemours, DuPont and Corteva – have reached an agreement in principle for US$1.19 bn to settle claims they contaminated US public water systems with PFAS.