On November 20, 2025, the U.S. Environmental Protection Agency (EPA) and the Department of the Army published their proposed rule to revise the definition of “waters of the United States” (WOTUS) under the Clean Water Act (CWA). Following more than a decade of litigation and WOTUS “repeal and replace” rulemaking, the current administration promotes this proposal as fully implementing the U.S. Supreme Court’s 2023 decision in Sackett v. EPA. In that case, the U.S. Supreme Court rejected the “significant nexus” test that extended WOTUS status to wetlands and other features if they were found by the agencies or courts to significantly affect the “chemical, physical, and biological integrity” of traditional navigable waters.

The proposed rule would establish a narrower scope of federal CWA jurisdiction through several revisions.

  • Actually Navigable and “Relatively Permanent” Water Bodies: Beyond traditionally navigable waters like rivers, lakes, and oceans, WOTUS jurisdiction would only extend to other tributaries, lakes, and ponds if they are standing or continuously flowing surface waters year-round or at least during a wet season.
  • Adjacent Wetlands: WOTUS wetlands would be limited to those abutting (touching) such jurisdictional waters and having continuous surface connections at least during their wet seasons.
  • Interstate Waters: Water features that simply cross state lines would no longer automatically qualify as WOTUS.
  • Clarify Exclusions: The definitions of excluded items such as ditches, prior converted cropland, and waste treatment systems would be clarified. Groundwater would be added to the expressly excluded features.
  • New Definitions: Other important terms like “tributary,” “continuous surface connection,” and “relatively permanent” would be newly defined.

Recent Guidance and Historical Context

This proposal follows a series of regulatory and judicial developments, including:

  • March 2025 Guidance: The EPA and the Army Corps issued field guidance on implementing the “continuous surface connection” standard post-Sackett.
  • 2023 Conforming Rule: After Sackett, the agencies amended the January 2023 WOTUS rule to remove the “significant nexus” test and align with the Court’s interpretation.
  • Prior Swings: The WOTUS definition has shifted over the course of multiple administrations – from the Obama administration’s 2015 Clean Water Rule, to the 2020 Navigable Waters Protection Rule issued during President Trump’s first term, and finally to the Biden-era revisions adopted in 2023.

Why It Matters

The definition of WOTUS determines which waters are subject to federal permitting and enforcement under the CWA, including:

  • Section 402 “NPDES” permits required for the point source discharge of pollutants, including certain stormwater discharges;
  • Section 404 “dredge and fill” permits required for construction and other activities disturbing wetlands; and
  • Section 311 oil spill prevention and response requirements.

What’s Next

Expect robust public engagement and continued litigation as this rule moves forward. While EPA and the Army Corps now have the Supreme Court’s direction thanks to Sackett, technical and legal disputes will inevitably arise. The agencies acknowledge that this proposed WOTUS definition would result in significant reductions to the WOTUS features subject to CWA permitting, though they have declined to quantify those ecological and regulatory impacts at this time.

The focus of the interpretive debate will likely shift to the revised rule’s new standard, “at least during the wet season,” serving as the temporal test that would be required for “relatively permanent” standing or continuously flowing surface water. Though undefined, the agencies indicate that they intend this season to include each extended period when a geographic feature has predictable, continuous surface hydrology, year after year, except for any periods of extreme drought.

Stakeholders should review the EPA’s proposed rule and fact sheets, take advantage of the agencies’ virtual meetings and other public outreach efforts, and consider submitting comments during the open period ending January 5, 2026. Robinson+Cole’s Environmental Practice Group will continue to monitor developments and provide updates concerning these and other CWA programs.