02/10/2023 - Clean Water Act

2022 Revised Definition of Waters of the United States (WOTUS)

by Abby Husselbee

On December 30, 2022, EPA and the Army Corps of Engineers released their final rule revising the definition of “waters of the United States” (WOTUS). This final rule builds on the rule currently in effect and modifies some elements to reflect the agencies’ interpretations of the Clean Water Act, Supreme Court case law, and scientific and technical recommendations. The agencies have jurisdiction under the Clean Water Act to regulate “navigable waters,” which the statute defines as “the waters of the United States, including the territorial seas,” and the definition of WOTUS is used to determine which waters receive Clean Water Act protection. 

This final rule comes as the Supreme Court is considering Sackett v. EPA, which will likely clarify how EPA should determine if a wetland should be protected under the Clean WaterAct. While it will be important to assess the implications of the Sackett decision, the agencies’ final rule allows for either of the two tests the Court is considering—Justice Kennedy’s significant nexus test or Justice Scalia’s relatively permanent standard.

In this paper, I examine the agencies’ legal basis for the new definition of WOTUS in the final rule, compare the final rule’s regulatory language to the existing regulatory language, and explain the changes. You can read or download my paper here.

For more information on this rule you can read our Regulatory Tracker page, and you can subscribe to our Tracker Updates monthly email for this and other rules.