Rapanos v. United States & Carabell v. United States

On November 17, 2025, the U.S. Environmental Protection Agency and Department of the Army announced the proposed rule Updated Definition of Waters of the “United States.” Learn more about the proposed rule.

The final "Revised Definition of 'Waters of the United States'" rule was published in the Federal Register on January 18, 2023, and the rule took effect on March 20, 2023. On August 29, 2023, the agencies issued a final rule amending the Code of Federal Regulations to conform the January 2023 Rule’s definition of “waters of the United States” to the Supreme Court decision in Sackett v. Environmental Protection Agency. The conforming rule amends the provisions of the agencies’ definition of “waters of the United States” in the January 2023 Rule that are invalid under the Supreme Court’s interpretation of the Clean Water Act in the Sackett decision. The conforming rule, "Revised Definition of 'Waters of the United States'; Conforming," became effective on September 8, 2023 upon publication in the Federal Register. In addition, the January 2023 Rule, as amended by the conforming rule, is not currently operative in certain states due to litigation, and the pre-2015 regulatory regime is being implemented instead consistent with the Supreme Court’s decision in Sackett. Please visit the Rule Status page for additional information about the status of the January 2023 Rule, as amended, and litigation. 

The agencies utilize the guidance listed below to implement the pre-2015 regulatory regime. Documents associated with guidance for implementing the definition of "waters of the United States" under the Clean Water Act following the Rapanos v. United States, and Carabell v. United States Supreme Court decision:

• Clean Water Act Jurisdiction Following the U.S. Supreme Court's Decision in Rapanos v. United States & Carabell v. United States (pdf) (1.03 MB, December 2, 2008)
• Questions and Answers Regarding the Revised Rapanos & Carabell Guidance (pdf) (75.55 KB, December 2, 2008)
• June 2007 Legal Memorandum (pdf) (280.82 KB, June 5, 2007)
  This guidance is superseded by the December 2008 guidance
• June 2007 Memorandum of Agreement regarding Coordination on Jurisdictional Determinations under Clean Water Act Section 404 in Light of the SWANCC and Rapanos Supreme Court Decisions (pdf) (114.17 KB, June 5, 2007)
• Rapanos v. United States - June 19, 2006 (pdf) (787.32 KB)