The US Supreme Court has restricted the Environmental Protection Agency’s (EPA) ability to regulate certain wetlands under the Clean Water Act, in a case named Sackett v. EPA. The judgment stated that the EPA’s interpretation of the wetlands that the Act covers was inconsistent with the legislation’s text and structure, and that the law only extends to “wetlands with a continuous surface connection to bodies of water that are ‘waters of the United States’ in their own right.” This decision reverses a previous ruling by the U.S. Court of Appeals for the 9th Circuit, which supported the EPA.

In a split decision, the court ruled unanimously in favor of the Sacketts, the Idaho landowners who initiated the case, but was divided 5-4 regarding the reasoning. The majority opinion by Justice Samuel Alito was supported by Chief Justice John Roberts and Justices Clarence Thomas, Neil Gorsuch, and Amy Coney Barrett.

In a concurring opinion, Justice Brett Kavanaugh, joined by Justices Sonia Sotomayor, Elena Kagan, and Ketanji Brown Jackson, criticized the majority’s “continuous surface connection” test, saying it deviates from the Act’s text, decades of consistent agency practice, and past court precedents. Kavanaugh warned this interpretation could lead to long-protected wetlands falling outside the law’s scope, leading to significant impacts on water quality and flood control nationwide. For example, wetlands separated by levees along the Mississippi River would no longer be regulated, and protection of the Chesapeake Bay could be diminished. Kavanaugh concluded that the court’s interpretation would generate regulatory uncertainty and have real-world implications.

The Supreme Court’s decision case will have broad implications for environmental regulation, water quality, and flood control in the United States.