On January 18, 2023, U.S. EPA and the Army Corps published new regulations in the Federal Register redefining the Clean Water Act term “navigable waters,” also known as “waters of the United States.” This version of the regulations repeals the Navigable Waters Protection Rule adopted in the final year of the Trump Administration and adopts a broader definition of “WOTUS” that is mainly based on the regulations adopted by the agencies in the mid-1980s, but it also incorporates the ”relatively permanent” and “significant nexus” concepts expressed in the plurality and concurring opinions in Rapanos v. United States, 547 U.S. 715 (2006).

On January 25, the Federalist Society hosted a video teleforum featuring Kevin Minoli and yours truly, in which we offered an overview and some analysis of the new rule and discussed what impact the pending Supreme Court decision in Sackett v. EPA may have on the new regulation.

Here are some charts that I prepared that compare the new regulation to the 2020 regulations that it replaces, and the 1986 regulations that it is largely based on.

Litigation is already pending against this new regulation, in one suit brought by a coalition of trade associations, and another brought by Texas Attorney General Ken Paxton. In our teleforum, Kevin had some interesting observations on one of the issues, which is whether the definition of “significant nexus” in the final rule just published is a logical outgrowth of the proposed rule under the Administrative Procedure Act.


As has become the norm with this critical element of the Clean Water Act over the past three administrations, you will need to stay tuned for further litigation developments.

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