EPA's Region 6 Office
Serving: Arkansas, Louisiana, New Mexico, Oklahoma, Texas, and 66 Tribal Nations
The legal definition for navigable waters I defined generally under Clean Water (CWA) Section 502(7). EPA's regulatory definition can be found at 40 CFR 110.1
For the purpose of the 40 CFR Part 112, the term navigable waters means the waters of the United States, including the territorial seas, and includes:
- All waters that are currently used, were used in the past, or may be susceptible to use in the interstate or foreign commerce, including all waters subject to the ebb and flow of the tide.
- All interstate waters, including interstate wetlands, mudflats, and sandflats;
- All other waters such as interstate lakes, rivers, streams (including intermittent streams, wetlands, mudflats, sandflats, sloughs, prairie potholes, wet meadows, playa lakes, or natural ponds, the use, degration, or destruction of which could affect interstate or foreign commerce including any waters that could be used for recreational purposes, or from which fish, or shellfish could be taken and sold in interstate or foreign commerce; or that are used or could be used for industrial purposes by industries in interstate commerce
The CWA has been interpreted to cover all surface waters, including any waterway within the U.S. Also included are normally dry creeks through which water may flow and ultimately end up in public waters, such as a river, stream, tributary to a river or stream, lake reservoir, bay, gulf, sea, or ocean within or adjacent to the U.S. The CWA's jurisdictional reach may also include groundwater if it is directly connected hydrologically with surface waters.