On November 17, 2025, the U.S. Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers (USACE) jointly issued a proposed rule aimed at providing a "common-sense" clarification of the definition of "waters of the United States" under the Clean Water Act. This rule was co-authored and analyzed by Charles Jacobi, an environmental analyst, and Merrit Cowden, an environmental project manager, both from the engineering and land planning firm Kimley-Horn, headquartered in Raleigh, North Carolina, with both working out of the firm's Fort Worth, Texas office. The views expressed are solely those of the authors.

Overall, the proposed rule aims to define and clarify the scope of federal jurisdiction over the Clean Water Act permitting process—an area that has been fraught with ambiguity over the past several years. According to an EPA fact sheet, the proposed rule would ensure that federal jurisdiction focuses on "relatively permanent, standing or continuously flowing bodies of water."

This language aligns with the U.S. Supreme Court's landmark 2023 decision in Sackett v. EPA. That decision significantly narrowed the bounds of federal jurisdiction by limiting Clean Water Act jurisdiction to "relatively permanent bodies of water" and wetlands with a "continuous surface connection" to such waters.

Reinforcing the Sackett Decision's Principles

The terms "relatively permanent" and "continuous surface connection" are central to this rule. The proposed rule explicitly reaffirms the original intent of the Sackett decision: relatively permanent waters should exist at least during the "wet season." The start, end, and duration of the wet season vary by geographic region, influenced by factors such as hydrology, environment, and topography, but the term is intended to describe predictable, long-term hydrological conditions within a region.

In simple terms, if a water body does not exhibit relative permanence during the wet season in a specific geographic area, it is likely not considered a federally jurisdictional water. This principle applies to tributaries, ponds, lakes, and pools. For example, in an area where the wet season is expected to last three months, a seasonal stream that only exhibits continuous flow for one month of the year would likely not be deemed jurisdictional; any adjacent wetlands, ponds, or pools connected to it could also be deemed non-jurisdictional.

Furthermore, the new rule requires wetlands to meet a new two-part test: in addition to existing during the wet season, the covered water body must also be adjacent to another jurisdictional water. Prior to the Sackett decision, wetlands could be deemed jurisdictional if they had a "significant nexus" to a jurisdictional water. At that time, analysts had to evaluate the flow characteristics and functions of a stream's "relatively permanent reaches" to determine if they had a substantial effect on the chemical, physical, or biological integrity of jurisdictional waters.

Given that the pre-Sackett language was overly broad, focusing jurisdiction on relative permanence and surface connection to jurisdictional waters is an attempt to simplify the analysis process for consultants, landowners, public agencies, and other stakeholders.

Significant Exclusion for Ditches

The new rule also provides clear guidance on the definition of "excluded ditches" and proposes significant changes to which ditches can be considered jurisdictional waters. The proposed rule excludes "ditches constructed or excavated in dry land" from jurisdiction.

According to the Federal Register text, even if such ditches connect to other jurisdictional waters, as long as they are constructed or excavated in dry land, they are not subject to jurisdiction under the proposed rule. This is a significant change: ditches constructed or excavated in dry land, even if they exhibit relatively permanent flow, do not meet jurisdictional requirements—whereas, as previously noted, relatively permanent flow is typically the core benchmark for determining jurisdiction.

Additionally, groundwater has historically not been considered a jurisdictional water, and the new rule reaffirms this exclusion by including "groundwater drained through subsurface drainage systems" within the definition of groundwater. This language is intended to exclude subsurface drainage systems, including tile drains and French drains, from jurisdiction.

The Path Forward

If the proposed rule is finalized—the public comment period ended on January 6, 2026, and the final rule is currently being developed—the regulatory path will provide greater certainty for developers, consultants, landowners, and other stakeholders. The text released by the EPA and USACE appears to reduce the number of water features subject to Clean Water Act jurisdiction.

When assessing jurisdiction, the proposed rule leaves very little room to deviate from the "relative permanence" and "continuous surface connection" benchmarks established by the Sackett decision. Landowners and other stakeholders will have a clearer understanding of which water features fall under jurisdiction and what parameters their projects must meet before being subject to the Clean Water Act. Overall, developers and consultants are expected to gain greater clarity in determining which aquatic features on a potential project site are likely or unlikely to be considered jurisdictional waters.