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Water: Wetlands

Clean Water Act Definition of "Waters of the United States"

Waters of the US Banner 1: flooded neighborhood
faucet pouring clean water into a clear glass
a large irrigation system in the middle of a field
a crane standing in wetlands
close-up photo of a crab under water
a large flock of geese flying above a wetland area
a person kayaking in a still lake with fall colored trees in the background
lakefront property with a dock and gazebo
a man standing in a river fishing

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Since 1972, the Clean Water Act has protected our health and environment by reducing the pollution in waterways. But over the past decade, interpretations of Supreme Court rulings have removed some critical waters from federal protection, and caused confusion about which waters and wetlands are protected from pollution and development.  As a result, many important waters now lack clear protection under the law, and businesses and regulators face uncertainty and delay.

Last April, the U.S. Environmental Protection Agency and U.S. Army Corps of Engineers released draft guidance to clarify protection of waters through clearer, less burdensome guidelines for determining which water bodies are to be kept safe from pollution and destruction.

About 230,000 public comments were received on the draft guidance and many of them recommended that EPA propose a rule to clarify Clean Water Act protections for waters of the U.S., in large part because a rule would increase regulatory clarity, consistency, predictability and effectiveness. The EPA and the Army Corps of Engineers have begun the process of proposing a rule to clarify the waters of the U.S. that are protected under the Clean Water Act.

The agencies are fully committed to a rulemaking process that is transparent and inclusive of all stakeholders. The agencies anticipate proposing a rule for public comment in 2012.  The anticipated focus of the proposed rule is on protection of smaller waters that feed into larger ones, to keep downstream water safe from upstream pollutants.  The focus will also be on reaffirming protection for wetlands that filter pollution and store water and help keep communities safe from floods.

More information on the Clean Water Act is available at Summary of the Clean Water Act.

Learn More About The Guidance

Background Information

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Previous EPA Statements on Waters of the US

Relevant Information about Water

Legal Background on Waters of the US

Regulatory Definition of Waters of the U.S.

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, prairiepotholes, wet meadows, playa lakes, or natural ponds, the use, degradation or destruction of which could affect interstate or foreign commerce including any such waters:

    4. (i) Which are or could be used by interstate or foreign travelers for recreational or other purposes; or
    (ii)(From which fish or shellfish are or could be taken and sold in interstate or foreign commerce; or
    (iii) 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 inparagraphs (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.

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