On January 18, 2023, the U.S. Environmental Protection Agency (“EPA”) and the Department of the Army published a new final rule to re-define “waters of the United States” (“WOTUS”) under the Federal Clean Water Act (“CWA”). Although the rule is set to take effect March 20, 2023, the looming U.S. Supreme Court decision in Michael Sackett, et ux v. EPA, et al., Docket No. 21-454(2022) could establish additional legal precedent as to what constitutes WOTUS and could enable further legal challenges to the rule. If the rule goes into effect, it would broaden the types of water bodies subject to CWA regulation, while providing some clarity with regard to some newly excluded water features.