Clean Water Act Jurisdiction

The U.S. Supreme Court issued the latest in a decades-long series of rulings redefining the scope of the federal Clean Water Act in Sackett v. EPA (2023). United States. Numerous prior rulings likewise prompted reconsideration of and conflict over the scope of the Act. SWANCC v. U.S. Army Corps of Engineers (2001) and Rapanos v. United States (2006) in particular created uncertainty for landowners, environmental advocates, and regulators about whether many types of wetlands, small and intermittent streams, and other waters are subject to federal jurisdiction.

The U.S. Environmental Protection Agency and U.S. Army Corps of Engineers (the key federal regulatory agencies) issued multiple joint guidance documents to assist field staff, followed by regulations. In 2015 the Obama administration issued a rule defining the waters of the U.S., but in 2019 the Trump administration repealed that rule. In 2020, the Trump Administration issued a "navigable waters protection rule" that further limited coverage of the Clean Water Act. In 2021, the Biden Administration announced its proposal to repeal the 2020 rule, and did so in 2022 while contemplating further rulemaking. While Federal courts have put each of these competing regulatory actions on hold at various times, the Supreme Court's 2023 decision will necessarily affect federal rulemaking and decisions. ELI has conducted continuing research and evaluations aimed at understanding the implications of judicial and regulatory changes, including a substantial focus on the implications of these changes for state programs designed to protect wetlands and waters.


  • In response to the churn in rulemaking and in anticipation of Sackett v. EPA, ELI released a detailed look at the condition of state protections for non-federal wetlands and waters. State Protection of Nonfederal Waters: Turbidity Continues (article) 
  • In 2022-23, ELI examined alternative strategies states and tribes may use to protect non-federal waters. Filling the Gaps (working paper)

Prior ELI work in this area includes: