The U.S. Supreme Court issued the latest in a series of rulings defining the scope of the federal Clean Water Act in 2023, in Sackett v. United States. Prior rulings also affected the reach of the Act, including SWANCC v. U.S. Army Corps of Engineers (2001) and Rapanos v. United States (2006), created great 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.