Enforcement and Inspection

EPA and Army Corps of Engineers Post Updates to WOTUS

The EPA and the Department of the Army Corps of Engineers (Corps) posted proposed updates to the definition of waters of the United States (WOTUS) in the Federal Register on December 7, 2021.

The proposed rule would define WOTUS as:

  • Traditional navigable waters, interstate waters, and the territorial seas and their adjacent wetlands;
  • Most impoundments of WOTUS;
  • Tributaries to traditional navigable waters, interstate waters, the territorial seas, and impoundments that meet either the relatively permanent standard or the significant nexus standard;
  • Wetlands adjacent to impoundments and tributaries that meet either the relatively permanent standard or the significant nexus standard; and
  • “Other waters” that meet either the relatively permanent standard or the significant nexus standard.

“The rule defines the ‘relatively permanent standard’ as ‘waters that are relatively permanent, standing or continuously flowing and waters with a continuous surface connection to such waters,’” according to a Lexology article by Thompson Hine LLP. “The ‘significant nexus standard’ is defined as ‘waters that either alone or in combination with similarly situated waters in the region, significantly affect the chemical, physical, or biological integrity of traditional navigable waters, interstate waters, or the territorial seas (the foundational waters).’ The proposed rule plays a balancing act between including the coverage of the 2015 Obama-era rule, while setting aside the categorical inclusions that brought that rule to a halt via litigation. The result will likely be an uptick in agency case-by-case analyses, as the agencies seek to apply the multiple standards set forth in the new definition.”


The Clean Water Act (CWA) was enacted by Congress in 1972 to “restore and maintain the chemical, physical, and biological integrity of the Nation’s waters.” The only problem was the “Nation’s waters” was not defined, and that definition has been one of the most fiercely contested and misunderstood definitions under the EPA’s jurisdiction. And, to make it even more confusing, that jurisdiction is shared with the Corps.

The Obama administration attempted to define WOTUS by expanding its definition to clarify which bodies of water are automatically covered by the CWA and which must still be dealt with on a case-by-case basis. That rule defined “automatically protected waterways” as any that have a bed, a bank, and a high-water mark, according to VOX. This included many streams that remain dry part of the year.

The Trump administration’s definition made a clear distinction between federally protected wetlands and state-protected wetlands. Its definition of WOTUS pulled “back federal oversight of at least 51 percent of wetlands and 18 percent of streams — many of which had been protected since the Reagan administration,” according to E&E News.

For many, the Obama administration’s definition was overreaching, and the Trump administration’s definition did too little. Both Obama’s and Trump’s WOTUS definitions were extremely controversial and the subject of multiple court battles.

The problem with defining WOTUS is that “[t]he transition from water to solid ground is not necessarily or even typically an abrupt one. Rather, between open waters and dry land may lie shallows, marshes, mudflats, swamps, bogs—in short, a huge array of areas that are not wholly aquatic but nevertheless fall far short of being dry land,” the Executive Summary of the proposed rule says.

In 2020, the EPA and the Corps issued the Navigable Waters Protection Rule (NWPR), which “provided less protection and could have allowed far more impacts to the nation’s waters than any rule that preceded it,” the Executive Summary continues. The NWPR was vacated by a federal court decision on August 30, 2021, leaving the agencies with the pre-2015 regulations as their only available rules to enforce.

Although the agencies “are not currently implementing the NWPR, the agencies are aware that further developments in litigation over the rule could bring the rule back into effect,” states the proposed rule. “For these reasons, among others…, the agencies have decided that prompt replacement of the NWPR through the administrative rulemaking process is vital.”