Proposed New Definition of the “Waters of the United States” – What May Change and Why It Matters

The Environmental Protection Agency (EPA) and the Army Corps of Engineers have proposed revisions to the definition of the “waters of the United States” (WOTUS) in 90 Fed. Reg. 52498 (Nov. 20, 2025) to align with the U.S. Supreme Court’s 2023 decision in Sackett v. EPA and to clarify federal jurisdiction under the Clean Water Act (CWA). The agencies characterize the proposal as a clarification – not an expansion – focused on predictability and administrability.

Under the proposed rule, WOTUS would include (1) traditional navigable waters and the territorial seas; (2) most impoundments of WOTUS; (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.

Key Changes at a Glance

• Interstate waters removed as a standalone category: Interstate waters would only be WOTUS if they fall within another jurisdictional category in the definition (e.g., as traditional navigable waters, relatively permanent tributaries, or adjacent wetlands meeting the connection test).
• New and clarified definitions to implement Sackett: The proposal adds definitions for “relatively permanent,” “continuous surface connection,” and “tributary,” and removes “intrastate” from the lakes-and-ponds category to streamline the structure.
• Relatively permanent waters clarified: The agencies propose to define “relatively permanent” as “standing or continuously flowing bodies of surface water that are standing or continuously flowing year-round or at least during the wet season;” ephemeral features are excluded.
• Tributaries narrowed and made more objective: The agencies propose to define “tributary” as “a body of water with relatively permanent flow, and a bed and bank, that connects to a downstream traditional navigable water or the territorial seas, either directly or through one or more waters or features that convey relatively permanent flow.” Non-relatively-permanent features along the tributary path generally sever jurisdiction, with a limited exception for certain water transfers; connections through natural or artificial features count only if those features convey relatively permanent flow.
• Continuous surface connection defined: The agencies propose to define “continuous surface connection” as “having surface water at least during the wet season and abutting (i.e., touching) a jurisdictional water.” This proposed definition provides a two-prong test that requires both (1) abutment of a jurisdictional water, and (2) having surface water at least during the wet season.
• Lakes and ponds: Retains jurisdiction over relatively permanent lakes and ponds with a continuous surface connection to traditional navigable waters or to tributaries; removes “intrastate” as redundant.
• Exclusions clarified:
  • Waste treatment systems are defined and retained;
  • Prior converted cropland exclusion tied to an abandonment test (no agricultural use at least once in five years) with conservation/fallowing treated as continued use;
  • Ditches excluded when constructed or excavated entirely in dry land; channelized or relocated tributaries remain jurisdictional; and
  • Groundwater expressly excluded, including tile-drained groundwater.

What This Likely Means for Development Projects

• Proposed WOTUS definition will narrow scope of federal jurisdiction under the CWA of development projects that involve wetland impacts.
• More bright lines and documentation standards for establishing jurisdiction; if the agencies lack adequate information, determinations will trend non-jurisdictional under the proposed framework.

How to Engage: The proposal invites public comment received on or before January 5, 2026.

Bottom line: If finalized, the rule would narrow federal jurisdiction to relatively permanent waters and truly adjacent wetlands, remove interstate waters as a standalone category, and clarify tributary, wetlands, and exclusions frameworks – shifting more responsibility for non-jurisdictional features to States, Tribes, and localities.