EPA Releases Seventh Set of UCMR 5 Data

On March 11, EPA released its seventh set of national drinking water data collected under the fifth Unregulated Contaminant Monitoring Rule (UCMR 5) for a total of 30 chemical contaminants (29 PFAS and lithium). UCMR 5 was published on December 27, 2021, and large, midsize, and a nationally representative sample of small public water systems have been collecting data on these 30 chemical contaminants since January 1, 2023.

The seventh data release includes all results received for UCMR 5 since the start of monitoring through January 16, 2025. The released data represents approximately 66% of the total results EPA expects to receive by completion of data reporting in 2026. With the normal lag between sample collection, analysis, and reporting, the data represent approximately 7 (of 12) quarters of monitoring results (i.e., Q1 2023 through Q3 2024). The seventh data release includes approximately 1.4 million sample results for 7,800 public water systems. EPA is updating results in the UCMR 5 Data Finder, UCMR 5 Data Summary, and Occurrence Data Files. UCMR 5 resources and Q&A also reflect that six of the 29 PFAS for which monitoring data are being collected are part of the EPA’s final PFAS National Primary Drinking Water Regulation (NPDWR).

UCMR 5 seventh data release includes updates to:

1. UCMR 5 Data Finder – Allows the public, along with federal, state, and local agencies, to easily locate, view, and summarize specific UCMR 5 results, as well as download those results to an Excel (.xlsx) spreadsheet. Results can be filtered by multiple fields. A video demo is available.
2. Occurrence Data Text Files – Recommended for those interested in large-scale data processing using statistical or data analysis software. These files contain analytical results and the additional data element and ZIP Code information reported by participating public water systems.
3. UCMR 5 Data Summary – National summary statistics by contaminant, health effects information, data considerations, and data definitions for the UCMR 5 Data Finder and Occurrence Data Text Files.
4. UCMR 5 Website Q&A – Answers to common questions on accessing and understanding the UCMR 5 data, and on PFAS and lithium in drinking water.