The Environmental Protection Agency has released its long-awaited proposed rule addressing levels of PFAS in drinking water across the United States.

Regulation of PFAS raises many complicated and difficult issues, as these are chemicals that have long been incorporated into articles of commerce for decades, making them somewhat ubiquitous.

The proposed rule is not surprising for those who have been following the issues of pending federal PFAS regulation. It will, however, present challenges, both technical and in terms of the public’s understanding of what PFAS in drinking water may mean.

Unlike the health advisory limits that EPA made public last summer, this proposal would establish legally enforceable levels for six PFAS substances known to occur in drinking water. EPA is, for the time being, advising communities and water purveyors to follow applicable state requirements (in those states that have them).  When the final federal standard goes into effect, states will be required to have a standard that is no less strict than the federal limits.

While there are multiple PFAS that will be covered by EPA’s proposed rule, a water system could exceed the federal standard when only one is present if it’s present in sufficient concentration. EPA has concluded that PFOA and PFOS are likely carcinogens and that there is no level for these contaminants that does not present a risk of adverse health effects. Accordingly, EPA is proposing an MCL of 4 parts per trillion (4 ppt), the lowest level based on the ability to reliably measure and remove these contaminants from drinking water.

The proposed rule would require that all community water systems and non-transient, non-community water systems conduct initial monitoring within three years after the rule is promulgated. The monitoring must be conducted at the entry point to the distribution system. Based on their size and source water, systems must conduct initial monitoring either twice or quarterly during a 12-month period based on the size of the system’s customers and whether the source is ground or surface waters.

In order to reduce costs for systems, they would be allowed to use previously collected monitoring data to satisfy the initial monitoring requirements, if the sampling was conducted using EPA Methods 533 or 537.1 as part of UCMR 5 or other state-level or other appropriate monitoring campaigns. Many state and federal monitoring programs currently meet the initial monitoring requirements. EPA is proposing not to allow composite samples, an approach in which equal volumes of water from multiple entry points are combined into a single container and analyzed as a mixture. EPA is not proposing to grant waivers from these requirements, but will be taking public comment on this question.

The proposed rule would require water systems to provide public notification on an MCL violation as soon as practicable, but no later than 30 days after the system learns of the violation.

Much more to follow on this; our environmental law team is staying on top of these developments both from a regulatory and litigation perspective.