What is the Unregulated Contaminant Monitoring Rule?

The U.S. Environmental Protection Agency (EPA) periodically requires public water systems throughout the nation to conduct monitoring under the Unregulated Contaminant Monitoring Rule (UCMR) for contaminants that may be present in drinking water but are not currently subjected to federal drinking water regulations.

EPA establishes a list of priority unregulated contaminants every five years that public water systems must monitor during a specified UCMR cycle, which typically runs for three calendar years. The results are used to inform future regulatory decisions at the federal level.

From Jan. 1, 2023, through Dec. 31, 2025, public water systems are conducting monitoring under the fifth UCMR (UCMR 5). EPA will release UCMR 5 monitoring data quarterly through 2026. 

What is UCMR 5? What is being monitored?

On Dec. 27, 2021, EPA published the requirements for UCMR 5 in the Federal Register. Between 2023 and 2025, public water systems sample for 30 chemical contaminants, including 29 per- and polyfluoroalkyl substances (PFAS) and lithium.

Who is required to monitor?

In Florida, a total of 414 public water systems are scheduled to participate in EPA's UCMR 5 monitoring program. This includes community water systems and non-transient, non-community water systems (e.g., schools, factories and hospitals that have their own water systems).

When are systems required to monitor?

One-third of participating systems in Florida will be required to monitor each year between 2023 and 2025.

Where can I find UCMR 5 results?

UCMR monitoring data will be uploaded quarterly on EPA's occurrence data webpage.

In addition, EPA rules require that all public water systems notify their customers on the availability of UCMR 5 results no later than 12 months after the results are known. Community water systems are also required to report UCMR 5 results in their annual consumer confidence reports.

Additional Information

Last Modified: Friday, Aug 18, 2023 - 07:59am