September 27, 2026.
The wetlands and waterways of Wisconsin's Leopold Wetland Management District are part of a national debate over how far federal Clean Water Act protections should extend.
The federal U.S. Fish and Wildlife Service manages nearly 13,500 acres of waterfowl production areas in 17 southeastern Wisconsin counties through the Leopold Wetland Management District. The district also administers conservation easements covering about 3,000 acres in 21 eastern Wisconsin counties. Its waterfowl production areas are open to wildlife-dependent recreation, including hunting, fishing, wildlife observation, photography and hiking, unless otherwise posted.
The U.S. Environmental Protection Agency and Department of the Army published a supplemental proposed rule in September 2026 seeking additional public comment on the definition of "waters of the United States," commonly called WOTUS, under the Clean Water Act. The agencies say the proposal is part of their effort to develop a final definition that fully implements the U.S. Supreme Court's 2023 decision in Sackett v. EPA.
How a Supreme Court lawsuit led to the proposed changes.
The current rulemaking follows a long-running legal dispute over federal authority to regulate wetlands.
In Sackett v. Environmental Protection Agency, the Supreme Court ruled in May 2023 that wetlands covered by the Clean Water Act must have a continuous surface connection to bodies of water covered by the Act, making it difficult to determine where the water ends and the wetland begins. The ruling rejected the broader "significant nexus" approach that federal regulators had previously used for some wetlands.
Following the ruling, the EPA and Department of the Army amended their 2023 WOTUS regulations to conform to the Court's decision. The September 2026 supplemental proposal is part of the agencies' continuing effort to develop a permanent federal definition consistent with Sackett.
What could change.
The supplemental proposal asks for comment on additional approaches to defining which wetlands and waters fall under federal Clean Water Act jurisdiction.
Among the issues being considered are definitions of "perennial," "relatively permanent" and "continuous surface connection." The proposal discusses perennial waters in terms of water that is present or continuously flowing throughout the year under ordinary conditions, while allowing for certain temporary interruptions.
The proposed changes could affect which wetlands and streams require federal permits or otherwise fall under federal Clean Water Act jurisdiction.
Potential scale of the change.
The potential impact has prompted concern from environmental organizations.
The Natural Resources Defense Council estimates that at least 94 percent of wetlands in the continental United States and about 79 percent of streams could be at risk of losing federal Clean Water Act protections under scenarios associated with the proposal.
Those figures are NRDC's analysis, not an EPA estimate.
Why Wisconsin wetlands matter.
According to the federal U.S. Fish and Wildlife Service, wetlands within the Leopold Wetland Management District provide habitat for waterfowl, grassland birds, pheasants, shorebirds, wading birds and other wildlife.
The agency manages the district's waterfowl production areas primarily to provide habitat for ducks and geese, while the wetlands and surrounding grasslands support many other species.
The district contains five watersheds. They include portions of the Wisconsin River, Rock River, Fox River and Milwaukee River watersheds. Lake Winnebago, the largest lake within the district's boundaries, flows into a Fox River tributary.
The Leopold Wetland Management District was established in 1993 and is named for conservationist Aldo Leopold.
Fish and Wildlife Service has its own federal role.
The WOTUS debate does not eliminate the separate authority of the U.S. Fish and Wildlife Service to manage federal conservation lands and wildlife habitat.
The Service administers the National Wildlife Refuge System and manages the Leopold district's waterfowl production areas for wildlife conservation. Federal law also gives the Service a role in the Clean Water Act process. Under Section 404, the Service can comment on applications submitted to the U.S. Army Corps of Engineers for permits involving the discharge of dredged or fill material into federally regulated waters.
The U.S. Army Corps of Engineers, rather than the Fish and Wildlife Service, generally administers the federal Section 404 dredge-and-fill permitting program. States may also administer approved Section 404 programs in certain waters.
Consequently, changing the definition of WOTUS would not remove the Fish and Wildlife Service's authority to manage the federally owned lands within the Leopold Wetland Management District. The principal question is whether particular waters qualify for the separate federal protections and permitting requirements of the Clean Water Act.
States can have their own wetlands protections.
The Sackett decision changed the scope of federal Clean Water Act jurisdiction. It did not prevent states from adopting or enforcing their own wetlands laws.
The EPA describes the federal Clean Water Act framework as one in which states and Tribes have important responsibilities for managing water resources. The federal WOTUS definition does not automatically become a state's definition of protected wetlands.
That means a wetland could fall outside federal WOTUS jurisdiction while remaining subject to Wisconsin state law or other applicable state, Tribal or local requirements.
The distinction is important: a change in federal jurisdiction does not automatically mean that a wetland becomes unregulated. It means the federal Clean Water Act would no longer provide that particular layer of protection.
Wisconsin Tribes have participated in WOTUS discussions.
Wisconsin Tribal Nations have previously participated in federal discussions concerning WOTUS.
For the current proposal, EPA and the Department of the Army specifically invite Tribal governments to request government-to-government consultation. The agencies acknowledge that changes in federal jurisdiction could affect Tribes differently from states because many Tribes rely on federal programs to administer Clean Water Act protections and some do not have the same regulatory programs or resources available to them.
There is no separate, longer comment deadline for Tribes under the current supplemental proposal. EPA says one-on-one meetings with Tribal governments must also be completed by the close of that comment period.
The U.S. Environmental Protection Agency and Department of the Army are accepting public comments through October 9, 2026, under Docket No. EPA-HQ-OW-2025-0322.
For Wisconsin residents and Tribal communities, the comment period provides an opportunity to describe specific wetlands, streams and waterways and explain their importance to wildlife, recreation, flooding, water quality, cultural resources or community life.
