The WSWC submitted comments to EPA and the Army Corps of Engineers on the Supplemental Notice of Proposed Rulemaking (SNPRM) on the updated definition of “Waters of the United States” (WOTUS) (91 FR 57284; Docket ID: EPA-HQ-OW-2025-0322). The letter reaffirmed the Council’s comments on the November 2025 proposed rule (90 FR 52498), with added emphasis that a one-size-fits-all national approach to Clean Water Act (CWA) regulation does not recognize the specific conditions and needs of the West.
The Council explained: “The West differs from the East both hydrologically and legally, and western states also differ from one another. Physical, hydrological, biological, and chemical differences between waters, both spatially and temporally, as well as considerable differences in legal doctrines that govern water in western states, mean that any federal effort to clarify CWA jurisdiction will inevitably impact each state differently.
“The WSWC urges the agencies to ensure that any final rule considers a regional approach to the definitions of terms such as ‘relatively permanent,’ with regions building upon existing classification systems based on hydrology, geology, and climate. Any final rule should also balance definitional clarity with flexibility in implementation to address the unique landscapes, flow regimes, and legal frameworks in various regions of the Nation.”
The Council deferred to its member states on the appropriate scope of “perennial,” “relatively permanent,” and “continuous surface connection,” noting that states are best positioned to understand their own landscapes, flow regimes, and seasonality. WSWC also offered to support a meeting or series of meetings to begin a joint federal, state, and tribal effort to map traditionally navigable waters.
As in its earlier comments, WSWC called for an enduring, broadly supported definition that treats states as co-regulators, a clear process for resolving jurisdictional disputes, joint mapping of jurisdictional waters, and no reduction in state water pollution control grant funding as a result of WOTUS changes.