UCMR5 and the New PFAS Monitoring Requirements
The EPA’s Unregulated Contaminant Monitoring Rule 5 (UCMR5), effective 2023–2025, required all public water systems serving 3,300+ people to test for 29 PFAS and lithium. Smaller systems were required to test if they were selected in a nationwide sample. This monitoring requirement generated the most comprehensive national dataset on PFAS in U.S. drinking water ever collected — covering approximately 10,000 water systems.
With the finalization of PFAS MCLs in April 2024, ongoing compliance monitoring replaced UCMR’s one-time sampling. Systems must conduct initial compliance monitoring — collecting samples from each entry point to the distribution system — within 3 years and continue periodic monitoring thereafter. Systems exceeding MCLs must increase monitoring frequency and begin treatment planning.
Testing Methods and Laboratory Requirements
Compliance monitoring must use EPA-approved methods: Method 537.1 and/or Method 533 for the compounds regulated under the MCL rule. Laboratories must be state-certified for these methods to generate data usable for compliance purposes. The expansion of PFAS testing has strained laboratory capacity in some states, creating backlog issues for utilities trying to meet monitoring deadlines.
Quality assurance and quality control requirements for PFAS analysis are rigorous: method blanks, matrix spikes, and duplicate analyses are required to verify that laboratory procedures are not introducing contamination (a significant concern given PFAS ubiquity in lab environments) and that analytical methods are performing correctly for each sample batch.
Consumer Access to Results
Consumers can access their water utility’s PFAS test results through multiple channels: the Annual Water Quality Report (Consumer Confidence Report) that utilities must provide each year; state drinking water databases that post compliance monitoring results; and EPA’s UCMR5 data portal, which has national search capability.
If your utility detects PFAS above MCLs, it is required to notify you within 30 days and take corrective action. During the period between detection and treatment installation, utilities must provide alternative water supplies or point-of-use filters to affected customers. Contacting your utility’s customer service or the state drinking water program with questions about PFAS results is your right as a ratepayer.