U.S. EPA and U.S. Dept. of the Army Announce a Supplemental Notice of Proposed Rulemaking on Waters of U.S. Rule

On September 4, 2026, the U.S. Environmental Protection Agency and U.S. Department of the Army announced a Supplemental Notice of Proposed Rulemaking to gather public input on additional regulatory language defining Waters of United States (WOTUS) to be considered in conjunction with the November 20, 2025 proposed rule (click here for our Field Notes article). This revision to the earlier proposed rule aims to implement the 2023 Supreme Court decision in Sackett et ux v. USEPA and seeks to establish clearer standards for determining which water bodies fall under federal jurisdiction.

The supplemental proposal “offers an additional opportunity for public engagement on a limited number [emphasis ours] of new regulatory alternatives, to be considered alongside those in the 2025 proposed rule.” Once the proposed rule is published in the Federal Register, the agencies will accept public comments for 30 days.

The additional regulatory options for consideration include a proposed definition of “perennial” and alternatives for defining “relatively permanent” and “continuous surface connection.”

The conceptual framework desired to be consistent with the Sackett case is to allow federal jurisdiction over only “relatively permanent waterbodies” tied to interstate and navigable waters and the territorial seas, and those specific adjacent wetlands that possess a “continuous surface connection” to them. The Supreme Court’s decision in Sackett stated that the Clean Water Act’s jurisdiction “extends only to those wetlands with a continuous surface connection to bodies that are waters of the United States in their own right, so that they are indistinguishable from those waters.” The agencies are currently seeking comment on only the following three formal terms and one alternative concept:

• “Defining ‘perennial’ in the regulatory text to mean ‘having standing or continuously flowing water every day of the year during ordinary conditions’ or, alternatively, to mean ‘surface water flowing continuously year-round,’ consistent with the 2020 Navigable Waters Protection Rule.”
• “Defining ‘relatively permanent’ to focus on those waters that are perennial bodies of water, except during anomalous events such as drought or dry spell or due to a non-anomalous event resulting in temporary interruption for no more than 30 consecutive days in any given year such as low tide or a regularly occurring dry spell.”
• “Defining ‘continuous surface connection’ to mean 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, with an exception for temporary interruptions in the surface water connection as the result of anomalous events such as drought or dry spell or a temporary interruption in the surface water connection lasting no more than 30 consecutive days in any given year as a result of non-anomalous events such as low tide or a regularly occurring dry spell.”
• “As an alternative, revising the current category of jurisdictional waters for adjacent wetlands to include only wetlands that are indistinguishably part of a traditional navigable water, the territorial seas, a jurisdictional impoundment, or a jurisdictional tributary (e., when surface water in a wetland 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). This alternative would also result in deleting the definition of ‘adjacent.’”

These proposed alternative definitions eliminate reference to “wet season,” which was referenced in the earlier draft definitions of “continuous surface connection” and “relatively permanent” published in the November 20, 2025 draft rule.

Key Takeaways

These definitions would effectively eliminate all ephemeral and intermittent streams from federal jurisdiction, along with all wetlands that do not exhibit surface water year-round (such as groundwater-driven wetlands with no visible surface water and runoff-driven wetlands that are dry for extended periods of the year). These changes would only be effective at the federal level and would not affect state jurisdiction.

Next Steps

It is expected that the proposed rule will be published in the Federal Register in the next few business days, at which time the formal 30-day public comment period will commence. Typically, Final Rules are then published approximately 90 days later. Details about commenting can be found on EPA’s Waters of the United States website. For more information or to understand how this rulemaking could affect your projects, please contact your project manager or the staff listed below.

Resources

1. Supplemental Notice of Proposed Rulemaking: Updated Definition of Waters of the U.S., September 4, 2026
2. US. EPA’s Waters of the U.S. website