EPA Releases Initial Nationwide Monitoring Data on PFAS

On March 14, 2023, the United States Environmental Protection Agency (EPA) announced a proposed National Primary Drinking Water Regulation (NPDWR) for six PFAS included in the fifth Unregulated Contaminant Monitoring Rule (UCMR 5) monitoring. If finalized, the proposal will require public water systems to monitor for these chemicals and maintain water quality with PFAS levels below these MCLs. It will also require public water systems to notify the public and reduce PFAS contamination if levels exceed the proposed regulatory standards. The proposed PFAS regulation does not require any actions until it is finalized. USEPA has projected that the rule will be finalized near the end of 2023 or early 2024 and, once finalized, drinking water systems will have three years from that date to comply with the new MCLs.

On August 17, 2023, the EPA released the first set of data collected under the UCMR 5. UCMR 5 will provide new data that will improve EPA’s understanding of the frequency and levels that PFAS and lithium are found in the nation’s drinking water systems, and help the Agency make determinations about future actions to protect public health under the Safe Drinking Water Act.

This initial data release represents approximately 7% of the total results that EPA expects to receive over the next three years. The Agency will update the results quarterly and share them with the public in EPA’s National Contaminant Occurrence Database (NCOD) until completion of data reporting in 2026.

Based on this limited initial set of data, EPA noted the following:

    • PFOA and PFOS are two of the most widely studied PFAS. One or each of these two PFAS was measured at or above EPA’s minimum reporting level (MRL), and therefore above EPA’s Health Advisory (HA) levels, in the first sampling event for 7.8-8.5% of PWSs with results to date.


    • The other two PFAS with EPA HA levels are HFPO-DA (“GenX chemicals”) and PFBS. HFPO-DA was measured above its HA level by 1 of 2,002 PWSs. PFBS was not found above its HA level.


    • HA levels have not been established for the other 25 PFAS that are part of UCMR 5.


  • EPA has not published a HA level for lithium but has calculated a Health Reference Level (HRL) for screening purposes. To date, 22% of PWSs have reported lithium results above the screening HRL.


For further information on the EPA national standard for PFAS in drinking water, refer to our original update published in March 2023.