EPA’s Supplemental WOTUS Proposal: What Permit Applicants Should Know

On 9 September 2026, the Environmental Protection Agency (EPA) and the US Army Corps of Engineers published a supplemental proposal to revise the definition of “waters of the United States” (WOTUS) under the Clean Water Act.¹ The supplemental proposal builds on the agencies’ November 2025 proposed rule and responds to the Supreme Court’s 2023 decision in Sackett v. EPA, which significantly narrowed the scope of waters subject to federal jurisdiction under the Clean Water Act and established a new framework for determining which waters fall within that jurisdiction.

In Sackett, the Supreme Court rejected the “significant nexus” test previously used by the agencies to determine whether certain waters were subject to federal jurisdiction.² Instead, the Supreme Court concluded that the Clean Water Act extends to relatively permanent bodies of water connected to traditional interstate navigable waters and, in the case of wetlands, requires a continuous surface connection between the