Opinion of the Court
Notice: This opinion is subject to formal revision before publication in the preliminary print of the United States Reports. Readers are requested to notify the Reporter of Decisions, Supreme Court of the United States, Washington, D. C. 20543, of any typographical or other formal errors, in order that corrections may be made before the preliminary print goes to press.
SUPREME COURT OF THE UNITED STATES
No. 21–454
MICHAEL SACKETT, ET UX., PETITIONERS v. ENVIRONMENTAL PROTECTION AGENCY, ET AL.
ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE NINTH CIRCUIT
[May 25, 2023]
Justice Alito delivered the opinion of the Court.
This case concerns a nagging question about the outer reaches of the Clean Water Act (CWA), the principal federal law regulating water pollution in the United States.[1] By all accounts, the Act has been a great success. Before its enactment in 1972, many of the Nation’s rivers, lakes, and streams were severely polluted, and existing federal legislation had proved to be inadequate. Today, many formerly fetid bodies of water are safe for the use and enjoyment of the people of this country.
There is, however, an unfortunate footnote to this success story: the outer boundaries of the Act’s geographical reach have been uncertain from the start. The Act applies to “the waters of the United States,” but what does that phrase mean? Does the term encompass any backyard that is soggy enough for some minimum period of time? Does it reach “mudflats, sandflats, wetlands, sloughs, prairie potholes, wet meadows, [or] playa lakes?”[2] How about ditches, swimming pools, and puddles?
