EPA Proposed Rule Defining Waters of the U.S. (WOTUS) Confines Regulatory Reach as Dictated by Supreme Court

EPA released a proposal to update the definition of Waters of the United States (WOTUS) last month in an attempt to resolve years of regulatory uncertainty and attempts to align federal jurisdiction with the Supreme Court’s 2023 Sackett decision. Sackett explicitly held that “the CWA extends to only those wetlands that are `as a practical matter indistinguishable from waters of the United States.’” The Court stated that this test “requires the party asserting jurisdiction over adjacent wetlands to establish `first, that the adjacent [body of water constitutes] . . . water[s] of the United States,’” (i.e., a relatively permanent body of water connected to traditional interstate navigable waters); and second, that the wetland has a continuous surface connection with that water, making it difficult to determine where the “water” ends and the “wetland” begins.

The proposal also attempts to reduce regulatory burdens and associated costs with compliance. To achieve these aims, EPA proposes narrowing the scope of jurisdiction to relatively permanent waters and wetlands that maintain a continuous surface connection to such waters. The rule also refines key terms, including “relatively permanent” and “tributary,” and clarifies long-debated exclusions for features such as certain ditches, prior converted cropland, waste treatment systems, and groundwater. EPA maintains that these updates directly address longstanding stakeholder requests for clearer, more predictable standards that lessen compliance uncertainty and litigation risk. The agency defines “relatively permanent” to mean “standing or continuously flowing bodies of surface water that are standing or continuously flowing year-round or at least during the wet season.” The agency defines “tributary” to mean “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.” Further, the proposed definition of “tributary” clarifies that a “tributary does not include a body of water that contributes surface water flow to a downstream jurisdictional water through a feature such as a channelized non-jurisdictional surface water feature, subterranean river, culvert, dam, tunnel, or similar artificial feature, or through a debris pile, boulder field, wetland, or similar natural feature, if such feature does not convey relatively permanent flow.

EPA also underscored the rule’s economic implications, noting that improved regulatory clarity stands to benefit farmers, ranchers, and developers who rely on consistent water-related permitting frameworks. The full proposal is available in the Federal Register, with a 45-day public comment period, due January 5, 2026. Given how frequently WOTUS has shifted across administrations, many view this proposal as the closest attempt yet at establishing a durable, commonsense framework. The proposal, if made permanent and remains unchanged by subsequent administrations, will reduce the areas required to obtain a pesticide general permit under the Clean Water Act’s National Pollutant Discharge Elimination System (NPDES), which has been a burden to aerial applicators making pesticide applications over or near these waters since EPA promulgated the rule in 2011.