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Waters of the United States (WOTUS) Rulemaking

About Waters of the United States

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Current Implementation of "Waters of the United States"

The definition of "waters of the United States" currently applicable is the definition promulgated in 1986/1988, implemented consistent with subsequent Supreme Court decisions and guidance documents. The 2015 revised regulatory definition of "waters of the United States" has been stayed nationwide by the U.S. Court of Appeals for the Sixth Circuit.  In response to this stay, EPA and the Department of the Army resumed nationwide use of the agencies’ prior regulations defining the term “waters of the United States.” 

On February 28, 2017, the President of the United States issued an Executive Order directing EPA and the Department of the Army to review and rescind or revise the 2015 Rule. The agencies are in the process of reviewing the 2015 Rule and considering a revised definition of "waters of the United States" consistent with the Executive Order.

On January 22, 2018, the Supreme Court held that the courts of appeals do not have original jurisdiction to review challenges to the 2015 Rule.  On January 31, 2018, the agencies signed a final rule adding an applicability date to the 2015 Rule. With this final rule, the agencies intend to maintain the legal status quo of pre-2015 implementation, thus providing continuity and certainty for regulated entities, states and tribes, and the public while the agencies continue to consider possible revisions to the 2015 Rule.

1986/1988 Regulatory Definition of "Waters of the United States"

40 CFR 230.3(s) The term waters of the United States means:

  1. All waters which are currently used, or were used in the past, or may be susceptible to use in interstate or foreign commerce, including all waters which are subject to the ebb and flow of the tide;
  2. All interstate waters including interstate wetlands;
  3. All other waters such as intrastate lakes, rivers, streams (including intermittent streams), mudflats, sandflats, wetlands, sloughs, prairie potholes, wet meadows, playa lakes, or natural ponds, the use, degradation or destruction of which could affect interstate or foreign commerce including any such waters:
    1. Which are or could be used by interstate or foreign travelers for recreational or other purposes; or
    2. (From which fish or shellfish are or could be taken and sold in interstate or foreign commerce; or
    3. Which are used or could be used for industrial purposes by industries in interstate commerce;
  4. All impoundments of waters otherwise defined as waters of the United States under this definition;
  5. Tributaries of waters identified in paragraphs (s)(1) through (4) of this section;
  6. The territorial sea;
  7. Wetlands adjacent to waters (other than waters that are themselves wetlands) identified in paragraphs (s)(1) through (6) of this section; waste treatment systems, including treatment ponds or lagoons designed to meet the requirements of CWA (other than cooling ponds as defined in 40 CFR 423.11(m) which also meet the criteria of this definition) are not waters of the United States.

Waters of the United States do not include prior converted cropland. Notwithstanding the determination of an area’s status as prior converted cropland by any other federal agency, for the purposes of the Clean Water Act, the final authority regarding Clean Water Act jurisdiction remains with EPA.

Guidance Documents on the Definition of "Waters of the United States"

Rapanos v. United States & Carabell v. United States

In 2007 and again in 2008, the agencies developed guidance for implementing the above 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.

Solid Waste Agency of Northern Cook County (SWANCC) v. United States

In 2001 and again in 2003, the agencies developed guidance to address the above definition of "waters of the United States" under the Clean Water Act following the SWANCC Supreme Court decision.

  • January 2003 Legal Memorandum discussing the scope of the Clean Water Act jurisdiction in light of the SWANCC ruling and related court decisions.
  • January 2001 Legal Memorandum describing which aspects of the regulatory definition of "waters of the United States" are and are not affected by SWANCC. This guidance is superseded by the 2003 guidance.


1989 Memorandum of Agreement - Allocates responsibilities between EPA and the Corps for determining the geographic scope of the 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 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 Interpretive Rule.

Supreme Court Rulings Related to Waters of the United States

Clean Water Rule

Related Information