Understanding WOTUS and Navigable Waters in 2026
Federal Clean Water Act (CWA) coverage is narrowing after the Supreme Court’s Sackett v. Environmental Protection Agency (Sackett) decision (2023) and a 2025 Environmental Protection Agency (EPA)/U.S. Army Corps of Engineers (USACE) proposal to align waters of the United States (WOTUS) with that ruling. Expect fewer federally regulated wetlands, more state-by-state differences, and continued uncertainty through 2026.
What counts as “navigable waters” today?
Post-Sackett, WOTUS includes traditional navigable waters, territorial seas, certain interstate waters, impoundments, tributaries that are relatively permanent, and adjacent wetlands that directly abut those waters through a continuous surface connection. Non-jurisdictional ditches do not create adjacency.
Recent changes
- Supreme Court decision in Sackett (May 2023): The CWA covers only waters that are relatively permanent and wetlands with a continuous surface connection to those waters. The Supreme Court rejected the “significant nexus” test.
- Conforming amendments (September 2023): EPA and the USACE removed the significant nexus standard, revised the definition of "adjacent," and clarified that interstate wetlands aren't automatically WOTUS.
- Field guidance (March 2025): EPA and the USACE directed that non-jurisdictional ditches, swales, pipes, and culverts don't create a continuous surface connection. Wetlands must directly abut the water.
- Proposed rule (November 2025): EPA and the USACE proposed definitions for “relatively permanent,” “tributary,” and “continuous surface connection.” If finalized, federal coverage will narrow further.
Where each rule applies
Implementation is split:
- The 2023 amended rule is in effect in 24 states, D.C., and territories.
- The pre-2015 regime and Sackett apply in 26 states, including Alabama, Alaska, Arkansas, Florida, Georgia, Idaho, Indiana, Iowa, Kansas, Louisiana, Mississippi, Missouri, Montana, Nebraska, New Hampshire, North Dakota, Ohio, Oklahoma, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, West Virginia, and Wyoming.
Kentucky now follows the 2023 amended rule except for certain litigants. Always check EPA’s “Current Implementation of Waters of the United States” page to check state status before filing permits.
Why it matters to industry and commerce
- Permitting: WOTUS defines whether projects need Section 404 (dredge/fill) and Section 402 (National Pollutant Discharge Elimination System) permits. A narrower federal scope can reduce federal permitting, but state and tribal programs may still apply.
- Design: Wetlands separated by berms or uplands and connected only by ditches or culverts likely do not qualify as WOTUS. Early jurisdictional determinations (JDs) and hydrologic documentation are critical.
- Risk: Multistate portfolios face uneven rules due to individual states having their own regulatory framework. The 2025 proposal could further limit federal reach, shifting responsibility to states. Multistate industry and commerce should prepare for state variability and litigation-driven changes.
The legal and regulatory arc: Why definitions keep changing
- Statute: The CWA regulates “navigable waters,” defined as “waters of the United States,” but doesn't define WOTUS.
- Court history: Court decisions have repeatedly reshaped and narrowed the definition of WOTUS. United States v. Riverside Bayview Homes, Inc. (1985) upheld adjacent wetlands; the scope narrowed when Solid Waste Agency of Northern Cook County v. U.S. Army Corps of Engineers (2001) limited isolated waters. Rapanos v. United States (2006) deepened uncertainty by introducing two competing tests, “relatively permanent” vs. “significant nexus,” leaving regulators and courts with ambiguity.
- Rulemaking swings:
- The 2015 Clean Water Rule broadened coverage.
- The 2020 Navigable Waters Protection Rule narrowed it, but the rule was later vacated.
- The 2023 WOTUS Rule was reshaped by Sackett and amended in August 2023.
- Current alignment: The 2023 amendments and 2025 proposal aim to match the Supreme Court’s standards.
Pending actions to watch in 2026
- Final rule: The 2025 proposal’s comment period closed on January 5, 2026. A final rule could standardize terms and further narrow jurisdiction.
- Litigation: Courts may lift or expand injunctions, changing which states apply which regime.
- Funding: Fiscal Year 2025 operations rely on continuing resolutions; WOTUS changes will come through rulemaking, not budget riders.
Practical steps for EHS and project teams
- Confirm your state’s regime before scoping.
- Request or update JDs early; document permanence and direct abutment.
- Track the 2025 proposal and submit comments where unclear.
Key to Remember: WOTUS and “navigable waters” definitions are narrowing, reducing some federal burdens but increasing state variability. For industrial and commercial projects, early jurisdictional work and state-specific permitting plans are essential to protect schedules and budgets.




















































