California Water Views

On September 4, 2026, the U.S. Environmental Protection Agency (EPA) and U.S. Army Corps of Engineers released a supplemental proposal to revise the definition of “waters of the United States” (WOTUS) under the Clean Water Act.

This follows a November 2025 proposal that drew more than 220,000 comments and reflects the Agencies’ continued effort to align WOTUS with the Supreme Court’s 2023 Sackett v. EPA decision.

The supplemental proposal focuses on three core concepts:

• “Relatively permanent” waters – The Agencies propose to drop the “wet season” construct and instead tie jurisdiction largely to whether a feature is perennial, with limited exceptions for droughts and short dry spells.
• “Perennial” – The proposal offers two options for defining this new term: (1) water present every day of the year under ordinary conditions, or (2) surface water flowing continuously year‑round. The Agencies seek input on which better reflects Sackett.
• “Continuous surface connection” – For jurisdiction over wetlands, the new definition would require perennial surface water that is continuously connected to a jurisdictional water such that it is difficult to tell where one ends and the other begins, while allowing for brief interruptions from drought or routine dry periods.

The proposal also reaffirms several points from the Agencies’ 2025 proposal: interstate waters are not automatically jurisdictional simply because they cross state lines; certain ditches, prior converted cropland, and waste treatment systems remain excluded; and groundwater is not WOTUS.

For a more in depth review of this new development, please read our eAlert here.