PFAS in drinking water are not currently regulated in the United States, however six perfluorinated compounds were monitored under EPA’s Third Unregulated Contaminant Monitoring Rule. The PFAS monitored under UCMR3 included: PFOS, PFOA, perfluorononanoic acid (PFNA), perfluorohexanesulfonic acid (PFHxS), perfluoroheptanoic acid (PFHpA) and perfluorobutanesulfonic acid (PFBS).
Following the UCMR3 testing, in May 2016, the EPA released health advisories for perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), making a lifetime health advisory for each compound, or a sum total of the two, of 0.07 parts per billion. In February 2020, the EPA proposed regulatory determinations for PFOS and PFOA in drinking water.