Clean Water Act Jurisdiction

The U.S. Supreme Court issued several rulings resulting in confusion over the scope of the federal Clean Water Act. 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.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 and changes in course. In 2015 the Obama administration issued a rule defining the waters of the U.S., but in 2019 the Trump administration repealed that rule.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 limits coverage of the Clean Water Act. In 2021, the Biden Administration announced its proposal to repeal the 2020 rule, and the U.S. government is currently operating under pre-2015 definitions largely instituted in the 1980s. 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 2006, ELI filed a “friend of the court” brief with the U.S. Supreme Court in Rapanos v. United States. ELI's amicus curiae brief represented ELI’s first (and only) participation in litigation. It focused on constitutional issues related to Clean Water Act jurisdiction. Justice Kennedy cited ELI’s brief favorably in his Rapanos concurrence, the opinion from the ruling that most courts and legal observers agree articulates the principal test for Clean Water Act jurisdiction.

  • In 2007, ELI published the Clean Water Act Jurisdictional Handbook. The updated 2012 version — Clean Water Act Jurisdictional Handbook (2d edition, 2012) has subsequently served as an accessible resource explaining the law, compiling the relevant scientific studies, and providing a set of jurisdictional checklists.

  • In 2007, ELI published Anchoring the Clean Water Act: Congress’s Constitutional Sources of Power to Protect the Nation’s Waters, which identifies the constitutional basis of Congress’s authority to protect waterways and explains what the Supreme Court has said about these constitutional powers in past cases.

  • In 2011, ELI published America’s Vulnerable Waters: Assessing the Nation’s Portfolio of Vulnerable Aquatic Resources since Rapanos v. United States, a report assessing what types of wetlands and waters are not being protected by the federal regulatory agencies since Rapanos. ELI examined U.S. Army Corps of Engineers and state regulatory practices to conduct this assessment. The report also evaluates which states lack regulatory programs for these waters. This report is a useful tool for state wetland professionals or conservation enthusiasts interested in filling gaps in federal regulation for vulnerable wetlands, streams, or other aquatic resources.

  • In 2013, ELI released a 50-state study identifying laws that can limit the ability of state agencies to protect wetlands, streams, and other water resources more broadly than federal law. The study, State Constraints: State-Imposed Limitations on the Authority of Agencies to Regulate Waters Beyond the Scope of the Federal Clean Water Act (May 2013), finds that over two-thirds of all U.S. states have versions of these “stringency” and property rights laws. This study was relied on by the EPA and Corps of Engineers in subsequent rulemakings.

  • After the January 2020 adoption of the "Navigable Waters Protection Rule" ELI identified the likely implications for state programs across the U.S.  In 2021-22 ELI is examining state and tribal opportunities to provide protection for waters and wetlands that are no longer waters of the United States.
  • The National Wetlands Newsletter, published by ELI since 1978, provided extensive coverage of the jurisdictional issue.