Proposed Revision to the Definition of “Waters of the United States”
By Timothy P. Atkinson, Esq.
The Clean Water Act of 1972 grants the federal government authority to regulate pollution in “waters of the United States,” commonly referred to as WOTUS. The precise meaning of this term determines which rivers, lakes, streams, and wetlands require federal permits for activities such as dredging, filling, or discharging pollutants.
On November 17, 2025, the U.S. Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers issued a proposed rule to revise the regulatory definition of WOTUS. The proposal was signed by EPA Administrator Lee Zeldin and Assistant Secretary of the Army (Civil Works) Adam Telle. The 186-page document responds directly to the Supreme Court’s 2023 decision in Sackett v. Environmental Protection Agency, which limited federal jurisdiction to wetlands that possess a continuous surface connection to relatively permanent bodies of water.
The proposed rule introduces several specific changes to the existing regulations (33 CFR 328.3 and 40 CFR 120.2):
- Eliminates interstate waters as a standalone category of jurisdictional waters.
- Removes the word “intrastate” from the category covering certain lakes and ponds.
- Adds regulatory definitions for the terms “relatively permanent,” “continuous surface connection,” “tributary,” “ditch,” “prior converted cropland,” and “waste treatment system.”
- Clarifies and narrows exclusions for waste treatment systems, prior converted cropland, ditches, and adds an explicit exclusion for groundwater.
Under the proposal, “relatively permanent” waters are defined as those that are standing or continuously flowing year-round or at least seasonally during a typical wet portion of the year. Wetlands qualify as waters of the United States only if they maintain a continuous surface connection to such relatively permanent waters, meaning the wetland and the water are indistinguishable without a clear physical barrier during normal wet conditions.
The agencies state that the revisions are intended to align the regulations with the Sackett decision, increase predictability for regulated entities, reduce permitting burdens, and respect state and tribal authority over land and water resources. The proposal also includes a Regulatory Impact Analysis that examines potential cost savings and forgone environmental benefits compared to the baseline of the Amended 2023 Rule.
The rule is currently a notice of proposed rulemaking. Public comments will be accepted for 45 days following official publication in the Federal Register (Docket ID No. EPA-HQ-OW-2025-0322). Two hybrid public meetings (in-person and virtual) will be held, with details available at https://www.epa.gov/wotus/public-outreach-and-stakeholder-engagement-activities. After reviewing comments, the agencies will publish a final rule.