Revisions To Establish the Sixth Unregulated Contaminant Monitoring Rule (UCMR 6) for Public Water Systems
Key claim: The EPA is proposing UCMR 6, which would require public water systems to monitor seven ultrashort organofluorine compounds (including certain PFAS), three pesticide metabolites, and 20 additional organic compounds not currently subject to national primary drinking water regulations.
Abstract
(Proposed Rule · Environmental Protection Agency) The U.S. Environmental Protection Agency (EPA or agency) is proposing the sixth Unregulated Contaminant Monitoring Rule (UCMR 6). Under the Safe Drinking Water Act (SDWA), the UCMR program gathers data about unregulated contaminant occurrence in drinking water. The proposed UCMR 6 would require public water systems (PWSs) to collect national occurrence data for seven ultrashort organofluorine compounds (including certain PFAS), three pesticide metabolites, 13 semivolatile organic compounds, and seven purgeable organic compounds. Subject to the availability of appropriations, the EPA will require all community and non-transient non-community water systems (CWSs and NTNCWSs) serving 3,300 or more people, and a representative sample of PWSs serving fewer than 3,300 people, to conduct monitoring. These contaminants are not currently subject to national primary drinking water regulations (NPDWRs), and the EPA is proposing to require the collection of drinking water occurrence data to inform agency decisions. The data collected will be publicly available. The EPA is also announcing two public meetings (via webinar) to discuss this proposal of the sixth Unregulated Contaminant Monitoring Rule (UCMR 6).
Why this matters
UCMR cycles are the primary mechanism by which EPA generates nationwide occurrence data used to decide whether to set enforceable drinking water standards, so the contaminants added in UCMR 6 signal which chemicals are candidates for future regulation. Including ultrashort-chain organofluorines is notable because these PFAS are highly mobile in water and have largely evaded prior monitoring, while adding pesticide metabolites and additional organics expands the compliance and analytical burden on public water systems.