Earlier this week, the U.S. EPA published the fifth Unregulated Contaminant Monitoring Rule (UCMR 5). Pursuant to the rule, all public water systems serving more than 10,000 people, as well as  public water systems serving between 3,300 and 10,000 people (but only if sufficient funding and lab capacity is available), will be required to conduct a 12-month long sampling program for 29 specified PFAS chemicals.  The rule will also require the same testing from 800 randomly selected systems that serve less than 3,300 people.

Nothing about the rule comes as a surprise.  Congress specifically instructed the agency to include the PFAS chemicals in this iteration of the UCMR in the National Defense Authorization Act for Fiscal Year 2020.

The rule is, however, indicative of the focus the federal government is putting on all things PFAS. Although monitoring will only be required for 29 of the thousands of PFAS chemicals, this limitation reflects technical considerations and not modesty of the government’s intention to act aggressively when it comes to PFAS in drinking water. The 29 included PFAS are all of those which can be detected with the two EPA-validated testing methods for PFAS, Methods 533 and 537.1.  It would not be surprising to see additional PFAS monitoring requirements imposed of public water systems, if and when methods for reliably detecting those chemicals gain acceptance with EPA.

Complete results from the monitoring program will not be known for some time. Sampling does not begin until the beginning of 2023 at the earliest, and it may last through the end of 2025 at some systems. EPA is already in the midst of setting drinking water standards for some PFAS. One question that this rule raises is how important the agency believes the results are to its ability to move forward with similar rulemakings for other PFAS. This is an issue we will be watching closely at Environmental Law Next.