2026-13263Proposed RuleSignificantWallet

EPA Expands Water Testing for New Chemicals

Published Date: 7/1/2026

Proposed Rule

Summary

The EPA is rolling out the sixth Unregulated Contaminant Monitoring Rule (UCMR 6) to check for new, sneaky chemicals in public drinking water. Big water systems serving 3,300+ people and some smaller ones will test for 30 different contaminants, including certain PFAS and pesticides, to keep our water safe. Comments and feedback are open until late August 2026, and the EPA will host fun online meetings to chat about the plan!

Analyzed Economic Effects

5 provisions identified: 2 benefits, 2 costs, 1 mixed.

Which water systems must test

The proposal would require public water systems (PWSs) to monitor for the UCMR 6 contaminants. Specifically, all community water systems (CWSs) and non-transient non-community water systems (NTNCWSs) serving 3,300 or more people would be required to conduct monitoring; all systems serving more than 10,000 people would be required to monitor; and a nationally representative sample of systems serving fewer than 3,300 people would be required to monitor.

EPA pays testing costs for small systems

The proposal notes that under the Safe Drinking Water Act (as amended by AWIA), the EPA must pay the reasonable cost of testing and laboratory analysis for applicable public water systems serving 10,000 or fewer people, subject to the availability of appropriations and appropriate laboratory capacity.

30 contaminants (including PFAS) to be tested

The EPA proposes that UCMR 6 would collect national occurrence data for 30 unregulated contaminants: seven ultrashort organofluorine compounds (including certain PFAS), three pesticide metabolites, 13 semivolatile organic compounds, and seven purgeable organic compounds. The occurrence data collected under UCMR 6 will be entered into the publicly available National Contaminant Occurrence Database (NCOD).

Monitoring timeline: 2028–2030 sampling

The proposal would set the UCMR 6 sample collection dates from January 2028 through December 2030. During that period, applicable public water systems would be required to collect and submit monitoring samples for the listed contaminants.

Key compliance and reporting deadlines

The proposal identifies proposed applicability and reporting dates: it proposes to use February 1, 2026 for determining which PWSs are subject to monitoring, and April 26, 2027 as a related applicability/contact date for large systems. The proposal also would set December 31, 2027 as the final date for PWSs to report specified contact, location inventory, and scheduling information.

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Key Dates

Published Date
Comments Due
7/1/2026
7/31/2026

Department and Agencies

Department
Independent Agency
Agency
Environmental Protection Agency
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