The Environmental Protection Agency (EPA) and Army Corps of Engineers have officially released a revised definition of “Waters of the United States” (WOTUS) which determines the scope of federal regulation under the Clean Water Act (CWA). The comment period for the revision will be open until April 15, 2019. The revised definition and comment submission information can be accessed here.
What would the redefinition do?
The redefinition would create six categories of regulated waters and eleven categories of exempted waters.
The six categories that would be regulated:
- Traditional
navigable waters, including the territorial seas;
- The previously separated categories of “navigable waters” and “territorial seas” would be merged, but regulation of these waters would not be altered.
- Tributaries
that contribute perennial or intermittent flow to such waters;
- Tributaries would not include any surface features that only flow as the result of precipitation. Ephemeral flows like dry washes and arroyos would be excluded.
- Certain
ditches;
- Only ditches that also satisfy the conditions of the tributary definition, and ditches constructed in an adjacent wetland would be included.
- Certain
lakes and ponds;
- Lakes and ponds that satisfy the conditions of traditional navigable waters would be included.
- Lakes and ponds that contribute a perennial or intermittent flow to other jurisdictional waters would also be included.
- Impoundments
of otherwise jurisdictional waters; and
- The redefinition would not alter the regulation of impoundments.
- Wetlands
adjacent to other jurisdictional waters.
- Wetlands would satisfy the requirement of adjacency if they “abut” or have a “direct hydrological surface connection” with other jurisdictional waters.
The eleven categories of waters that would be exempted:
- Waters or water features that are not identified in the six categories of regulated waters.
- Groundwater, including groundwater drained through subsurface drainage systems.
- Ephemeral features and diffuse stormwater run-off.
- Certain ditches.
- Prior converted cropland.
- Artificially irrigated areas that would revert to upland if artificial irrigation ceases.
- Certain artificial lakes and ponds constructed in upland.
- Certain water-filled depressions created incidental to mining or construction activity and pits excavated for the purpose of obtaining fill, sand, or gravel.
- Stormwater control features excavated or constructed in upland to convey, treat, infiltrate, or store stormwater run-off.
- Wastewater recycling structures constructed in upland.
- Waste treatment systems.
The background of WOTUS

The definitions of “Navigable Waters” and “Waters of the United States” have changed multiple times since the creation of the CWA in 1972. The most recent redefinition occurred in 2015 and expanded CWA scope, including increased jurisdiction regarding ephemeral water features and water features adjacent but lacking direct hydrological connections to jurisdictional waters.

Source: Environmental Protection Agency
Since its introduction, the 2015 definition has faced litigation regarding its validity under the Constitution and the CWA. As a result, the rule has been blocked in 28 States and is currently only recognized in 22 States, the District of Columbia, and U.S. Territories. In states where the 2015 rule is blocked, the EPA’s less-inclusive 1988 definition of “Waters of the United States” remains in effect.
On February 28, 2017, President Trump signed the Executive Order “Restoring the Rule of Law, Federalism, and Economic Growth by Reviewing the `Waters of the United States’ Rule.” This order began the process of developing the currently proposed redefinition. The intention of this redefinition as stated in the Executive Order is “to ensure that the Nation’s navigable waters are kept free from pollution, while at the same time promoting economic growth, minimizing regulatory uncertainty, and showing due regard for the roles of the Congress and the States under the Constitution.”
The official revised WOTUS definition was released on February 14, 2019 and the comment period on the rule will be open until April 15, 2019. The latest fact sheets, infographics, supporting documents, information on the revision can be accessed here on the EPA’s website.