11/21/2025

EPA Proposes New WOTUS Definition

On November 17, 2025,  the U.S. Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers (Corps) released a pre-publication proposed rule to revise yet again the definition of “waters of the United States” (WOTUS) under the Clean Water Act.

The proposed rule reflects the most recent change in the scope of WOTUS jurisdiction. Since the Supreme Court’s 2001 decision in Solid Waste Agency of Northern Cook County v. Army Corps of Engineers, EPA and the Corps have repeatedly shifted their interpretation of WOTUS, at times expanding it and at times narrowing it.

As we explained in our prior client alert, just months before the landmark decision in Sackett v. Environmental Protection Agency in 2023, in which the Supreme Court announced its narrowest definition of WOTUS to date, EPA and the Corps had published an expanded definition for WOTUS, particularly as it applied to wetlands.

In Sackett, the Supreme Court constrained the scope of WOTUS, finding federal jurisdiction over waterbodies includes only “relatively permanent, standing or continuously flowing bodies of water” and wetlands “that have a continuous surface connection” to those waters.

Subsequently, EPA and the Corps under the Biden administration were forced to issue a new final rule in September 2023, which narrowed the scope of wetlands that qualify as WOTUS, but seemed in conflict with the changes required by Sackett. The new proposed rule, this time from the Trump administration, is intended to provide further clarity about the Sackett decision and for several other areas of uncertainty.

In particular, the proposed rule makes the following changes:   

  • Eliminates the stand‑alone interstate waters category and removes “intrastate” from lakes and ponds; jurisdiction turns on permanence and connection to traditional navigable waters or the territorial seas.

  • Defines the following terms to help implement the Sackett decision:

    • “Continuous surface connection”: Wetlands must meet a two-part test to have a continuous surface connection and be jurisdictional: (1) they must abut a jurisdictional water, and (2) they must have surface water at least during the wet season. Under the proposed rule, culverts do not inherently sever the continuous surface connection.

    • “Relatively permanent waters”: Waterbodies that are relatively permanent are “standing or continuously flowing year-round or at least during the “wet season.”

    • “Tributary”: A tributary is a body of water with relatively permanent flow, and a bed and bank, that connects to a downstream traditional navigable water or the territorial seas, either directly or through one or more waters or features that convey relatively permanent flow.

  • Clarifies that ditches constructed or excavated entirely in dry land are not WOTUS, even if they have a relatively permanent flow and connect to jurisdictional waters. The only "ditches" that fall outside of this exclusion are tidal or navigable ditches (e.g., canals).

  • Clarifies that all components of waste treatment systems are not WOTUS.

  • Adds an explicit groundwater exclusion, codifying the historic understanding that groundwater is not WOTUS.

  • Clarifies that ephemeral waters are not jurisdictional because they are not relatively permanent.

The comment period on the proposed rule ends on January 5, 2026. For more information regarding the proposed rule, or for help in providing comments to EPA and the Corps, please contact Lisa Gilbreath (207.791.1397), Brian Rayback (207.791.1188), Michelle O’Brien (617.488.8146) or Georgia Bolduc (207.791.1249).