EPA, Corps Release WOTUS Revisions
On September 4, 2026, the U.S. Environmental Protection Agency (EPA) released a pre-publication version of proposed revisions to the definition of “water of the United States” (WOTUS) in the context of federal Clean Water Act (CWA) implementation (Proposed Rule). The Proposed Rule is, in fact, the second time in less than a year that the EPA and U.S. Army Corps of Engineers (Corps) have released a proposed definition of WOTUS. The EPA and Corps (together, Agencies) previously published proposed revisions to the WOTUS definition on November 17, 2025 (2025 Proposal).
The 2025 Proposal would have removed from the definition WOTUS a number of features previously included as WOTUS, would have dispensed with providing automatic jurisdiction for interstate waters, and provided definitions for terms such as “continuous surface connection,” “ditch,” “prior converted cropland,” “relatively permanent,” “tributary,” and “waste system.” The 2025 Proposal received more than 220,000 public comments, and as stated in the preamble to the Proposed Rule, the Agencies determined that supplementing the 2025 proposal was warranted.
In the Proposed Rule, the Agencies seek public comment on alternative regulatory definitions for the terms “relatively permanent” and “continuous surface connection” than the definitions set forth in the 2025 Proposal, as well as a proposed new definition for the term “perennial.” Additionally, the Agencies confirm their intent to remove from automatic CWA jurisdiction interstate waters so that the mere fact that a water crosses state lines would not, by itself, cause that water to fall within the definition of WOTUS. The Agencies also confirm their previously proposed exclusions for waste treatment systems, prior converted cropland, and certain ditches. They again emphasize that groundwater is not WOTUS.
In the 2025 Proposal, the Agencies defined “relatively permanent” as “standing or continuously flowing bodies of surface water that are standing or continuously flowing year round or at least during the wet season.” The 2025 Proposal’s reliance on a defined “wet season” drew many comments expressing concern about how to interpret the phrase and its inherent ambiguity. The Agencies’ supplemental option for defining “relatively permanent” as set forth in the Proposed Rule would dispense with considerations of “wet season” and, instead, find a feature to be jurisdictional only where that feature is perennial. The Proposed Rule does provide certain exceptions from a requirement that a feature be perennial, such as where the flow dries up from anomalous drought or due to non-anomalous events like low tide or a dry spell.
To further provide clarity, the Proposed Rule also provides two possible definitions of the term “perennial,” for which the Agencies seek comment. Under the first option, the term “perennial” would mean a feature that has “standing or continuously flowing water every day of the year during ordinary conditions.” Under the section option, the term “perennial” would mean “surface water flowing continuously year-round.” In the preamble to the Proposed Rule, the Agencies emphasize their consideration of which definition of the term “perennial” most closely reflects the Supreme Court’s interpretation of the CWA in Sackett. They specifically solicit public comments regarding tools for interpreting these concepts for implementation, like metrics for determining whether a non-anomalous dry spell or anomalous drought is occurring.
Similar to its supplemental definition of the phrase “relatively permanent”, the Agencies’ are proposing an alternative definition of the phrase “continuous surface connection” that would not rely on considerations of the wet season. Under the 2025 Proposal, the definition of “continuous surface connection,” as that term is used to determine whether a wetland is jurisdictional, meant having surface water at least during the wet season and abutting a jurisdictional water. Under the Proposed Rule, the Agencies have dropped the wet season concept and, instead, would define “continuous surface connection as “perennial surface water in a wetland that is continuously connected with the surface water in the jurisdictional water such that it is difficult to determine where the jurisdictional water ends and the wetland begins.” The alternative definition set forth in the Proposed Rule also clarifies that:
[a] temporary interruption in the surface water connection may occur as the result of anomalous events such as drought or a dry spell. A temporary interruption in the surface water connection lasting for no more than a single period of up to 30 consecutive days in any given year may also occur as a result of non-anomalous events such as low tide or a regularly occurring dry spell.
In addition to seeking public comment on the alternative definition for “continuous surface connection,” the Agencies seek specific feedback on whether the U.S. Supreme Court’s decision in Sackett v. EPA (Sackett) would support inclusion of the terms “adjacent” or “abutting” in the definition of “continuous surface connection” or whether Sackett supports removing those terms entirely.
The Agencies will accept public comments on the Proposed Rule through October 9, 2026.
