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Waters of the United States

About Waters of the United States

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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 discretion 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 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 discretion 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, the Court rejected a claim of federal jurisdiction over non-navigable, isolated, intrastate ponds that lack a sufficient connection to traditional navigable waters, noting that the term ‘‘navigable’’ must be given meaning within the context and application of the statute. The Court held that the use of “isolated” non-navigable intrastate ponds by migratory birds was not by itself a sufficient basis for the exercise of federal regulatory authority under the Clean Water Act. 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 two federal district courts that reviewed the merits of the 2015 Clean Water Rule found that the rule suffered from certain errors and issued orders remanding the 2015 Clean Water Rule back to the agencies. Multiple other federal district courts preliminarily enjoined the 2015 Clean Water Rule, such that more than half of the states continued to implement the 1980s regulations and not the 2015 Clean Water Rule. 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 following document related to the 2015 Clean Water Rule is provided for informational purposes only.

The agencies replaced the 2019 Rule with the Navigable Waters Protection Rule in 2020.

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Current Implementation of “Waters of the United States

On June 9, 2021, EPA and Department of the Army announced their intent to initiate a new rulemaking process that restores the protections in place prior to the 2015 WOTUS implementation and develops a new rule to establish a durable definition of “waters of the United States.” This rulemaking process follows a review conducted by the agencies as directed by January 20, 2021 Executive Order 13990 on “Protecting Public Health and the Environment and Restoring Science to Tackle the Climate Crisis.” Further details of the agencies’ plans, including opportunity for public participation, will be conveyed in a forthcoming action.

On April 21, 2020, EPA and the Department of the Army (Army) published the Navigable Waters Protection Rule in the Federal Register to finalize a revised definition of “waters of the United States” under the Clean Water Act. The rule became effective on June 22, 2020, and is currently being implemented by EPA and the Army across the country. Read the final rule.

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. 

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Additional Past Guidance Documents on the Definition of “Waters of the United States”

Because the Navigable Waters Protection Rule is in effect across the country, the guidance materials listed below are no longer applicable. They are provided for informational purposes only.

  • January 2003 Legal Memorandum discussing the scope of the Clean Water Act jurisdiction in light of the SWANCC ruling and related court decisions.

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After finalizing the Navigable Waters Protection Rule, the agencies developed several memoranda applicable to the definition of “waters of the United States.” Those memoranda can be found here.

The memoranda listed below are also related to the definition of “waters of the United States” regardless of the regulations defining “waters of the United States.”

1989 Memorandum of Agreement - Allocates responsibilities between EPA and the Corps for determining the geographic scope of the CWA Section 404 program and the applicability of exemptions from regulation under Section 404(f).

1979 “Civiletti” Memorandum - U.S. Attorney General opinion on ultimate administrative authority under CWA Section 404 to determine the reach of navigable waters and the meaning of Section 404(f).

Clean Water Act Section 404 and Agriculture - Includes the 1990 Memorandum to the Field and the Memorandum withdrawing the March 2014 "U.S. Environmental Protection Agency and U.S. Department of the Army Interpretive Rule Regarding the Applicability of Clean Water Act Section 404(f)(l)(A)."

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Supreme Court Rulings Related to “Waters of the United States”

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