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On November 20, 2025, the EPA and U.S. Army Corps of Engineers (the agencies) issued proposed revisions to the regulatory definition of “waters of the United States” (WOTUS), a term that outlines the scope of the Clean Water Act’s (CWA) jurisdiction. Updated Definition of ‘‘Waters of the United States,’’ 90 Fed. Reg. 52498. The proposed rule seeks to align the WOTUS definition with the Supreme Court’s May 25, 2023, decision in Sackett v. EPA and resolve certain implementation-related issues, most notably defining “relatively permanent” and “continuous surface connection,” both of which are specifically used in the Sackett decision to limit CWA jurisdiction.
In September 2023, the agencies published a final rule that amended the regulations defining WOTUS in response to the Supreme Court’s Sackett decision. As a result of the final rule, jurisdictional waters, with certain listed exclusions, are now: (1) traditional navigable waters, territorial seas, interstate waters; (2) impoundments of WOTUS; (3) tributaries of the aforementioned waters that are relatively permanent, standing or continuously flowing bodies of water; (4) wetlands having a continuous surface connection to WOTUS; and (5) intrastate lakes and ponds, streams, or wetlands that are relatively permanent, standing or continuously flowing bodies of water with a continuous surface connection to navigable waters, territorial seas, or interstate waters. 40 C.F.R. § 120.2(a); 33 C.F.R. § 328.3(a).
However, the agencies note in the preamble to the proposed rule that they have heard “numerous concerns raised by stakeholders” regarding the September 2023 rule, including that it “does not adequately comply” with the Sackett Court’s interpretation of the scope of CWA jurisdiction. Thus, the agencies are proposing to revise the September 2023 rule to implement the Sackett decision and reduce regulatory uncertainty by clarifying what constitutes WOTUS. In particular, the agencies are defining key terms such as “relatively permanent” and “continuous surface connection” and are further clarifying and expanding major exclusions.
Definition of “Relatively Permanent”
The proposed rule defines “relatively permanent” to mean “standing or continuously flowing bodies of surface water that are standing or continuously flowing year-round or at least during the wet season.” The phrase “at least during the wet season” is meant to include “extended periods of predictable, continuous surface hydrology occurring in the same geographic feature year after year in response to the wet season, such as when average monthly precipitation exceeds average monthly evapotranspiration.”
The agencies state that they intend to use metrics from the Web-based Water-Budget Interactive Modeling Program (WebWIMP), which are reported in an Army Corps of Engineers tool for informing wetlands delineations and jurisdictional determinations, “as a primary source for identifying the wet season.” The agencies also provide that this “wet season” approach “can be viewed as a bright line test, as it would provide a duration threshold requirement for which an abutting wetland or an abutting lake or pond must have surface water in order to be considered jurisdictional.” Further, “Unlike typical bright line approaches, … the agencies’ proposed approach would also allow for regional variation given the range in hydrology and precipitation throughout the country.”
Definition of “Continuous Surface Connection”
The agencies are not revising the definition of “adjacent,” which means “having a continuous surface connection,” but are proposing to define “continuous surface connection” to mean “having surface water at least during the wet season and abutting (i.e., touching) a jurisdictional water.” Thus, the agencies’ proposed definition of “continuous surface connection” provides a two-prong test that “requires both (1) abutment of a jurisdictional water; and (2) having surface water at least during the wet season.”
The proposed rule states the agencies intend that the term “wet season” in the definition of “continuous surface connection” be implemented in the same manner as described under the definition of “relatively permanent.”
Clarification and Expansion of Exclusions
In addition, the proposed rule clarifies and expands upon the regulatory status of certain exclusions, including by:
- Removing interstate waters and intrastate lakes and ponds from the WOTUS definition to make clear that such waters are not WOTUS unless they are otherwise jurisdictional.
- Explaining that “excluded ditches” means “those non-navigable ditches (including roadside ditches) that are constructed or excavated entirely in dry land, even if those ditches have relatively permanent flow and connect to a jurisdictional water.”
- Clarifying the “waste treatment system” and “prior converted cropland” exclusions through the addition of definitions for those terms.
- Underscoring that groundwater is not considered WOTUS through a proposed exclusion.
Comments on the proposed rule must be submitted by January 5, 2026. Stay tuned for further updates. For more information, contact Liskow attorneys Greg Johnson, Clare Bienvenu, Emily von Qualen, and Colin North, and visit Liskow’s The Louisiana Industrial Insights Hub to stay up-to-date on further WOTUS developments.
"With this proposed rule, the agencies intend to provide greater regulatory certainty and increase Clean Water Act program predictability and consistency by clarifying the definition of ‘waters of the United States.’"