Definition of "Waters of the United States" under the Clean Water Act
- What are "Waters of the United States?"
- History of "Waters of the United States
- Current Implementation of Waters of the United States
- Supreme Court Rulings Related to Waters of the United States
What are "Waters of the United States?"
The 1972 amendments to the Clean Water Act established federal jurisdiction over “navigable waters,” defined in the Act as the “waters of the United States” (CWA Section 502(7)). Many Clean Water Act programs apply only to “waters of the United States.” The Clean Water Act provides authority for EPA and the U.S. Department of the Army (Army) to define “waters of the United States” in regulations.
History of "Waters of the United States"
“Waters of the United States” is a threshold term in the Clean Water Act and establishes the geographic scope of federal jurisdiction under the Act. Clean Water Act programs, including Water Quality Standards, TMDLs, and sections 311, 402, and 404 address “navigable waters,” defined in the statute as “the waters of the United States, including the territorial seas.”
The Clean Water Act does not define “waters of the United States”; rather, it provides authority for EPA and the U.S. Department of the Army to define “waters of the United States” in regulations.
Since the 1970s, EPA and the Department of the Army have defined “waters of the United States” by regulation. In the mid-1980s, both agencies promulgated a definition of “waters of the United States.”
Three Supreme Court decisions have addressed the definition of “waters of the United States.” In 1985, in United States v. Riverside Bayview Homes, Inc., the U.S. Supreme Court deferred to the Corps’ assertion of jurisdiction over wetlands adjacent to a traditional navigable water, stating that adjacent wetlands may be regulated as "waters of the United States" because they are ‘‘inseparably bound up’’ with navigable waters and ‘‘in the majority of cases’’ have ‘‘significant effects on water quality and the aquatic ecosystem’’ in those waters.
In Solid Waste Agency of Northern Cook County v. U.S. Army Corps of Engineers (SWANCC) in 2001, a 5-4 Court held that the use of "nonnavigable, isolated, intrastate waters" by migratory birds was not by itself a sufficient basis for the exercise of Federal authority under the Clean Water Act. SWANCC, 531 U.S. at 172. The Court noted that in Riverside Bayview, it had "found that Congress' concern for the protection of water quality and aquatic ecosystems indicated its intent to regulate wetlands 'inseparably bound up with the "waters" of the United States'" and that "[i]t was the significant nexus between the wetlands and 'navigable waters' that informed [the Court's] reading of the Clean Water Act" in that case. Id. at 167. In 2001 and again in 2003, the agencies developed guidance to address the definition of “waters of the United States” under the Clean Water Act following the SWANCC decision.
The Court most recently interpreted the term ‘‘waters of the United States’’ in Rapanos v. United States in 2006. A four-Justice plurality stated that ‘‘waters of the United States’’ ‘‘include[ ] only those relatively permanent, standing or continuously flowing bodies of water ‘forming geographic features’ that are described in ordinary parlance as ‘streams[,] . . . oceans, rivers, [and] lakes,’” and ‘‘wetlands with a continuous surface connection’’ to a ‘‘relatively permanent body of water connected to traditional interstate navigable waters.’’ In a concurring opinion, Justice Kennedy took a different approach, concluding that ‘‘to constitute ‘navigable waters’ under the Act, a water or wetland must possess a ‘significant nexus’ to waters that are or were navigable in fact or that could reasonably be so made.’’ He stated that adjacent wetlands possess the requisite significant nexus if the wetlands ‘‘either alone or in combination with similarly situated lands in the region, significantly affect the chemical, physical, and biological integrity of other covered waters more readily understood as ‘navigable.’’’ The four dissenting Justices, who would have affirmed the court of appeals' application of the agencies' existing regulation, concluded that the term "waters of the United States" encompasses all tributaries and wetlands that satisfy either the plurality's standard or Justice Kennedy's. Following Rapanos, in 2007 and again in 2008, the agencies developed additional guidance for implementing the "waters of the United States" definition.
The agencies amended their regulations defining “waters of the United States” in 2015 in the Clean Water Rule: Definition of "Waters of the United States."
The 2015 Clean Water Rule was repealed by the 2019 Rule, which reinstated the 1980s regulations, implemented consistent with the U.S. Supreme Court cases and applicable guidance.
The agencies replaced the 2019 Rule with the Navigable Waters Protection Rule (NWPR) in 2020. The agencies are in receipt of the U.S. District Court for the District of Arizona's August 30, 2021 order vacating and remanding the Navigable Waters Protection Rule in the case of Pascua Yaqui Tribe v. U.S. Environmental Protection Agency. In light of this order, the agencies have halted implementation of the NWPR nationwide and are interpreting "waters of the United States" consistent with the pre-2015 regulatory regime.
For additional information, see the History of the Effects of Litigation Over Recent Definitions of "Waters of the United States" (pdf) .
On December 30, 2022, the agencies announced the final "Revised Definition of 'Waters of the United States'" rule which will be effective 60 days after it is published in the Federal Register. More information about the final rule is available here.
Current Implementation of "Waters of the United States"
The Environmental Protection Agency and U.S. Army Corps of Engineers ("the agencies") are in receipt of the U.S. District Court for the District of Arizona’s August 30, 2021, order vacating and remanding the Navigable Waters Protection Rule (NWPR) in the case of Pascua Yaqui Tribe v. U.S. Environmental Protection Agency. In light of this order, the agencies have halted implementation of the NWPR nationwide and are interpreting “waters of the United States” consistent with the pre-2015 regulatory regime.
On December 30, 2022, the agencies announced the final "Revised Definition of 'Waters of the United States'" rule which will be effective 60 days after it is published in the Federal Register. The agencies developed this rule with consideration of the relevant provisions of the Clean Water Act and the statute as a whole, relevant Supreme Court case law, and the agencies’ technical expertise after more than 45 years of implementing the longstanding pre-2015 “waters of the United States” framework. This rule also considers the best available science and extensive public comment to establish a definition of “waters of the United States” that supports public health, environmental protection, agricultural activity, and economic growth. More information about the final rule is available here.
If a state, tribe, or an entity has specific questions about a pending jurisdictional determination or permit, please contact a local U.S. Army Corps of Engineers District office or EPA.
Learn more about the agencies' current implementation of "waters of the United States."
- Supreme Court decision in National Association of Manufacturers v. Department of Defense et al. – January 22, 2018
- Supreme Court decision in Rapanos v. U.S. and Carabell v. U.S. - June 19, 2006
- Supreme Court decision in Solid Waste Agency of Northern Cook County v. U.S. Army Corps - January 9, 2001
- Supreme Court decision in United States v. Riverside Bayview Homes, Inc. - December 4, 1985