Jump to main content or area navigation.

Contact Us

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

You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more.

Clean water is the nation's most valuable natural resource and is relied on for drinking, recreation, manufacturing, energy development, agriculture, commercial fishing, tourism, and many other purposes that are essential to public health and the economy.

Since 1972, the Clean Water Act has protected our health and environment by reducing the pollution in streams, lakes, rivers, wetlands and other waterways. But over the past decade, interpretations of Supreme Court rulings have removed some waters from federal protection, and caused confusion about which waters and wetlands remain protected.  

In April 2011, the EPA and the U.S. Army Corps of Engineers released draft guidance to clarify protection of waters under the Clean Water Act. About 230,000 public comments on the draft guidance were received by the agencies. Most recognized the importance of effective implementation of the Clean Water Act to protect human health and water quality.

EPA and the Army Corps of Engineers have submitted final guidance to clarify protection of waters under the Clean Water Act to the Office of Management and Budget for federal interagency review. The guidance will provide more predictable and consistent procedures for identifying waters and wetlands protected under the Clean Water Act.

The guidance is focused on protection of smaller waters that feed into larger ones, to keep downstream water safe from upstream pollutants. The focus is also on reaffirming protection for wetlands that filter pollution and store water and help keep communities safe from floods.

The guidance will not extend federal protection to any waters not historically protected under the Clean Water Act and will be fully consistent with the law, including decisions of the Supreme Court. The guidance will also maintain all of the existing exemptions for agricultural discharges and waters, and also identify specific types of water bodies to which it does not apply – areas like artificial lakes and ponds, and many types of drainage and irrigation ditches.

EPA and the Corps of Engineers have also heard requests from Congress, industry organizations, environmental groups, states and the public for rulemaking to further clarify the requirements of the Clean Water Act consistent with decisions of the Supreme Court. The agencies propose to finalize the guidance and to continue work on a rulemaking.

Learn More About The Guidance

Background Information

Select from the list below to expand the view and read further information on that topic.

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, 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:

    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 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.

Jump to main content.