Agencies Propose Latest Revision of Clean Water Act “Waters of the United States” Definition

EPA and the U.S. Army Corps of Engineers (USACE) recently proposed revisions to regulations defining the scope of waters covered under the Clean Water Act (CWA). For over 50 years, CWA regulations have been the subject of extensive rulemaking and litigation, primarily due to the contentious history surrounding the definition of “waters of the United States” (WOTUS). 

Following the 2023 Supreme Court decision in Sackett v. Environmental Protection Agency, which narrowed the scope of federal jurisdiction under the CWA, the agencies proposed further revisions to the CWA regulations.¹ These revisions aim to provide clarity, simplicity, consistency, and longstanding improvements to the regulatory program (the “Proposed Rule”). The comment period for this proposed rulemaking closed January 5, 2026.²

Proposed Changes

The Proposed Rule represents the agencies’ latest effort to address the complex history associated with the WOTUS definition and the CWA regulations. Under the agencies' recently proposed rule, the term “waters of the United States” would include: (1) traditional navigable waters and the territorial seas; (2) most impoundments of “waters of the United States;” (3) relatively permanent tributaries of traditional navigable waters, the territorial seas, and impoundments; (4) wetlands adjacent (i.e., having a continuous surface connection) to traditional navigable waters, impoundments, and tributaries; and (5) lakes and ponds that are relatively permanent and have a continuous surface connection to a traditional navigable water, the territorial seas, or a tributary.

The Proposed Rule includes the following notable revisions to the CWA regulations:

Removal of the interstate waters category from the definition of “waters of the United States.”

• Removal of “intrastate” from the paragraph (a)(5) category for lakes and ponds that are not identified in paragraph (a)(1) through (a)(4) that are relatively permanent, standing or continuously flowing bodies of water with a continuous surface connection to the waters identified in paragraph (a)(1) or (a)(3) of that section.
• Amendment of the exclusions for waste treatment systems, prior converted cropland, and certain ditches.
• Addition of an exclusion for groundwater.
• Addition of the definitions for the following:
  • “continuous surface connection”
  • “ditch”
  • “prior converted cropland”
  • “relatively permanent”
  • “tributary”
  • “waste treatment system”

Impacts on Virginia

Although the Proposed Rule would redefine federal jurisdiction under the WOTUS, it is important to note Virginia maintains its own jurisdiction over state waters, including wetlands. Many water bodies throughout the state remain subject to this jurisdiction due to Virginia’s expansive definition of “state waters” and its comprehensive regulatory framework. Under the Virginia State Water Control Law (SWCL), “state waters” are defined as “all water, on the surface and under the ground, wholly or partially within or bordering the Commonwealth or within its jurisdiction, including wetlands.”³ While the SWCL does not define surface water, the State Water Control Board (SWCB) has defined surface water as “all state waters that are not groundwater as groundwater is defined in § 62.1-255 of the Code of Virginia.”⁴

As a result, state waters in Virginia will continue to be subject to state-level regulations, including permitting and mitigation for impacts that fall under the Virginia Water Protection Permit Program.

Looking Forward

Despite Virginia’s comprehensive regulatory framework for state waters, regulated parties should carefully consider implications of the Proposed Rule on CWA § 404 permitting, CWA § 402 NPDES discharges and permitting, CWA release reporting and response, and the extent of Total Maximum Daily Load requirements, Oil Pollution Act and Spill Prevention, Control, and Countermeasure/ Facility Response Plan coverage. Furthermore, it is important to thoroughly assess the potential impacts on federal funding for current or pending projects involving waters that would no longer be classified as WOTUS. Stakeholders must remain informed and engaged to ensure project compliance and to effectively manage and protect water resources for the future.