The EPA is responsible for identifying maximum contaminant levels (MCLs) to regulate drinking water, as outlined in the Safe Drinking Water Act. As of June 2020, there are no federal regulations on the maximum levels of PFAS allowed in drinking water.

The EPA has established a non-enforceable health advisory level of 70 parts per trillion (ppt) for the sum of PFOA and PFOS. Health advisories are non-regulatory and provide technical information to state agencies and other public health officials on health effects, analytical methodologies, and treatment technologies associated with drinking water contamination. The EPA is working toward determining future PFAS regulations; visit the agency’s webpage on EPA Actions to Address PFAS to learn more. 

In the absence of federal limits, states such as California have established their own regulatory limits on PFAS. In the state of California,  the state Department of Drinking Water has established notification levels of 6.5 ppt for PFOS and 5.1 ppt for PFOA, and response levels of 10 ppt for PFOA and 40 ppt for PFOS. Other states such as Arizona currently rely solely upon the EPA health advisory level to assess and determine necessary actions related to PFOA and PFOS.