Update, January 18, 2023: The Final Rule was issued today and will be effective March 20, 2023.

On December 30, 2022, the U.S. Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers (Corps) released a pre-publication version of the latest attempt at updating and codifying the definition of Waters of the U.S. (WOTUS). This rule attempts to codify the longstanding pre-2015 regulatory regime with guidance from Supreme Court case law such as Rapanos v. United States (2006). The changes in protections for WOTUS have been difficult to navigate with three new defining Rules and a host of related lawsuits and federal court decisions over the past seven years (since the implementation of the Clean Water Rule in 2015). The EPA is emphasizing that they believe this new Rule will be durable.

What’s the Same?

The definition of WOTUS should look familiar and includes traditional navigable waters, territorial seas, interstate waters, impoundments, tributaries, adjacent wetlands, and additional waters. The terms “wetland,” “adjacent,” and “ordinary high-water mark” remain the same as in the 1986 regulations. Although not defined in the Rule, the preamble explains that “a tributary includes rivers, streams, lakes, ponds, and impoundments, regardless of their flow regime, that flow directly or indirectly through another water or waters to a traditional navigable water, the territorial seas, or and interstate water.” (page 277, emphasis WSSI’s)

What’s New (but Still the Same)?

The post-Rapanos standards of “relatively permanent” and “significant nexus” have been added under the Final Rule.

The relatively permanent standard encompasses surface waters that have flowing water year-round or continuously during certain times of the year and does not include surface waters with flowing or standing water for only a short duration in direct response to precipitation (page 293). This idea is consistent with the Rapanos-related guidance although the term “seasonal” has been removed to allow for more clarity and those situations where flow may not follow naturally recurring annual or seasonal cycles.

The significant nexus standard is codified in this rule to be used to determine if waters are protected by the Clean Water Act. The term “significantly affect” has been added to the definitions in order to guide the significant nexus determination. “Significantly affect” for this Rule’s purpose means “a material influence on the chemical, physical, or biological integrity of waters identified in a paragraph (a)(1) of this section”. Under this rule, waters, including tributaries or wetlands, are evaluated either alone or in combination with other similarly situated waters in the region based on defined functions the evaluated waters perform and specific factors to considered to determine if there is a material influence on a traditional navigable water, the territorial seas, or an interstate water.

Exclusions have also been codified to provide clarity, consistency, and certainty to stakeholders. Many of these have, in practice, been used since the inception of the Clean Water Act. These exclusions include:

  • Prior converted cropland
  • Waste treatment systems
  • Ditches
  • Artificially irrigated areas
  • Artificial lakes and ponds
  • Artificial reflecting pools or swimming pools
  • Waterfilled depressions
  • Swales and erosional features

JDs Issued Under Previous Rules

This new rule confirms that any existing Approved Jurisdictional Determination (AJDs) – except AJDs issued under the vacated 2020 Navigable Waters Protection Rule (NWPR) – will remain valid to support regulatory actions, such as permitting, until the expiration date of the AJD.  While AJDs issued under the NWPR had already been with the vacatur, AJDs issued subsequently will remain valid under this rule.

What Does This Mean for My Projects?

While the rule is new, the information in it has been around for a while and generally reflects the current state of the federal view of jurisdictional waters. We therefore do not anticipate any significant changes to the features on which we currently see the agencies exert jurisdiction.  Additionally, any wetlands not considered jurisdictional under the new rule will continue to be covered by state regulatory authority such as in Maryland and Virginia, as well as in D.C.

WSSI Can Help

Contact your WSSI Project Manager or the staff listed below to discuss how this relates to your projects and any potential implications of the new Rule.



  • Ben Rosner, PWS, PWD, CE

    Director - Environmental Science

    Gainesville, VA

  • Rebecca Napier, PE

    Manager - Natural Resources

    Richmond, VA

  • Bob Kerr, PWS, PWD

    Director - Hampton Roads

    Virginia Beach, VA

  • Mike Klebasko, PWS, QFP

    Manager - Maryland Environmental Science

    Millersville, MD