Waters of the U.S.

On August 29, 2023, the U.S. Environmental Protection Agency (EPA) and Department of the Army (the agencies) issued a final rule to amend the final “Revised Definition of ‘Waters of the United States’” rule, published in the Federal Register on January 18, 2023. This final rule conforms the definition of “waters of the United States” to the U.S. Supreme Court’s May 25, 2023, decision in the case of Sackett v. Environmental Protection Agency. Parts of the January 2023 Rule are invalid under the Supreme Court’s interpretation of the Clean Water Act in the Sackett decision. Therefore, the agencies have amended key aspects of the regulatory text to conform it to the Court’s decision. The conforming rule, "Revised Definition of 'Waters of the United States'; Conforming," published in the Federal Register and became effective today 8 September 2023.

Where the January 2023 Rule is not enjoined, the agencies are implementing the January 2023 rule, as amended by the conforming rule. In the jurisdictions and for the parties where the January 2023 Rule is enjoined, the agencies are interpreting the phrase “waters of the United States” consistent with the pre-2015 regulatory regime and the Supreme Court’s decision in Sackett. The below map illustrates which definition of “waters of the United States” is generally operative in each state across the country as a result of litigation challenging the 2023 Rule. The map is also available at https://www.epa.gov/wotus/definition-waters-united-states-rule-status-and-litigation-update. As the litigation continues, EPA will update the map, when possible, to reflect the most current information that is made available to the EPA and the Army.

Information about “waters of the United States” is available on the EPA’s website and documents used to implement the pre-2015 regulatory regime are available here. The EPA has also posted webinars from September on the September 2023 conforming rule, as well as state and tribal webinars from November that cover the amended 2023 rule and the pre-2015 regulatory regime.

The U.S. Army Corps of Engineers has updated versions of the Automated Wetland Determination Data Sheets (ADS), to reflect revisions to the final 2022 National Wetland Plant List (NWPL). The updated ADS can be found here under the “General Information” dropdown. More info regarding the ADS and its utility in wetland delineation can be found here. 

The NWPL provides plant species wetland indicator status ratings, which are used in determining whether the hydrophytic vegetation factor is met when conducting wetland delineations under the Clean Water Act and wetland determinations under the Wetland Conservation Provisions of the Food Security Act. Other applications of the NWPL include wetland restoration, establishment, and enhancement projects. The list is effective as of 13 February 2024 and will be used in any wetland delineations performed after this date.

Completed wetland delineation/determination forms should reference the version of the NWPL used to complete the form. The final NWPL is available here (preferred browsers are Chrome and Firefox). While the web address for the NWPL website has not changed with this update, the website itself has undergone updates to enhance the utility of the NWPL.