On April 21, 2020, U.S. EPA and the Army Corps of Engineers published the final Navigable Waters Protection Rule amending the definition of “Waters of the United States” (the “2020 WOTUS Rule”). Under the 2020 WOTUS Rule, four categories of jurisdictional WOTUS are subject to regulation under the Clean Water Act (CWA):

1. The territorial seas and traditional navigable waters,
2. Perennial and intermittent tributaries to those waters,
3. Certain lakes, ponds, and impoundments, and
4. Wetlands adjacent to jurisdictional waters

The 2020 WOTUS Rule also identifies 12 categories of water features that are excluded from the definition of WOTUS, including ephemeral features, groundwater, and several ditches. In an effort to provide clarity and maintain consistency with the express language of the Clean Water Act, the 2020 WOTUS Rule revises the definition of several key terms and includes newly defined key terms. Some of the new and revised key terms defined under the final 2020 WOTUS Rule include: “tributary”; “adjacent wetlands”; “upland”; “waste treatment system”; “perennial”; “intermittent”; and “ephemeral”.

The 2020 WOTUS Rule is effective on June 22, 2020. Once effective, the 2020 WOTUS Rule replaces the October 2019 “Step One Rule,” which repealed the 2015 WOTUS Rule and re-codified the pre-2015 rules. Litigation surrounding the 2015 WOTUS rule was plentiful and contentious. The 2020 WOTUS Rule is expected to face similar legal challenges.