EPA Proposes to Further Scale Back Federal Jurisdiction Over WOTUS
On September 4, 2026, the U.S. Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers (Corps) issued a supplemental proposed rule to further revise the definition of “waters of the United States” (WOTUS). The proposal would further narrow federal jurisdiction under the Clean Water Act (CWA) by replacing the “wet season” test for determining covered waters with a new requirement that the body of water be at least “perennial” to qualify as WOTUS.
EPA and Corps Seek to Clarify Key Definitions
The agencies’ November 2025 proposal to use states’ “wet seasons” to determine jurisdiction and apply certain exclusions generated significant confusion and concern in comments submitted during the ongoing rulemaking.
The proposal defined “relatively permanent” waters as “standing or continuously flowing bodies of surface water that are standing or continuously flowing year-round or at least during the wet season,” explaining that the phrase “at least during the wet season” was intended to encompass extended periods of predictable, continuous surface hydrology occurring in the same geographic feature year after year.
The November 2025 proposal also defined “continuous surface connection” as “having surface water at least during the wet season and abutting (i.e., touching) a jurisdictional water.” Thus, the proposed definition established a two-prong test that requires both a surface connection to a jurisdictional water and the presence of surface water at least during the wet season.
In an effort to provide greater clarity, the agencies are now seeking comments on revised definitions of “relatively permanent,” “perennial,” and “continuous surface connection.”
“Relatively Permanent” Would Mean Perennial
The agencies propose a supplemental definition for “relatively permanent” to mean “perennial bodies of water.” That definition would also state that “[a] body of water does not lose its relatively permanent status if it dries up for no more than a single period of up to 30 days in any given year as a result of non-anomalous events resulting in a temporary interruption such as low tide or a regularly occurring dry spell.”
Thus, if a body of water experiences an interrupted flow for two periods in any given year, and each period consists of 10 consecutive days, the water body would not qualify as relatively permanent. The agencies anticipate that most intermittent streams would not meet the supplemental “relatively permanent” definition.
Additionally, the agencies propose to define “perennial” as “having standing or continuously flowing water every day of the year during ordinary conditions.” They also seek comment on whether to define “perennial” to simply mean “surface water flowing continuously year-round.”
A Narrower Approach to “Continuous Surface Connection”
Finally, EPA and the Corps are seeking comment on a revised definition of “continuous surface connection,” a term that arises from the Supreme Court’s 2023 decision in Sackett v. EPA. While the November 2025 proposal defined “continuous surface connection” as having surface water at least during the wet season and touching a jurisdictional water, they now seek comment on an alternative definition that would require “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 agencies anticipate that most wetlands currently considered jurisdictional as adjacent wetlands would not satisfy the supplemental definition of “continuous surface connection,” because most wetlands do not contain perennial surface water.
What Happens Next?
This proposed supplemental rule is the latest development in a 20-year effort to define the scope of federal authority over wetlands under the CWA. We have extensively covered the evolving scope of WOTUS jurisdiction across administrations, including in our prior client alert and the related alerts linked therein.
Once the supplemental proposal is published in the Federal Register, the agencies will accept public comments for 30 days. 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), Michelle O’Brien (617.488.8146), or Georgia Bolduc (207.791.1249).