Illinois has few remaining wetlands. A Trump administration proposal could decimate what’s left.

The Environmental Protection Agency calls wetlands “biological supermarkets” for the sheer abundance of food they supply to a broad range of species. Roughly 40 percent of all plants and animals rely on wetlands for some part of their lifecycle. These ecosystems also filter drinking water, blunt the force of flooding, and store vast amounts of carbon dioxide — functions that make them critical in efforts to combat climate change. But the EPA and Army Corps of Engineers are now moving to slash federal protections for the nation’s wetlands and streams, potentially leaving millions of acres of habitat in Illinois and the Midwest vulnerable to being dug up, filled in, or paved over.

At the heart of the proposal announced last week is a new, stricter definition to the long-debated legal term, “Waters of the United States,” the federal guidance that determines which bodies of water are protected under the 1972 Clean Water Act. The proposal codifies a 2023 Supreme Court decision that limits federal protection to wetlands that are so inseparable from larger, relatively permanent bodies of water like streams, rivers, and lakes that you can’t tell where one ends and the other begins. Under the proposed rule, wetlands must contain water during the “wet season” and must be connected to a major waterbody during that season. Effectively, the new definition excludes seasonal streams and wetlands, which remain dry for much of the year.

“We’re looking at up to 85 percent of the country’s wetlands losing their protected status under the Clean Water Act,” said Andrew Wetzler, the Natural Resources Defense Council’s senior vice president for nature. 

A 2025 analysis from the nonprofit environmental group found that approximately 70 million of the 84 million acres of wetlands across the country are at risk. Under the current regulations, developers must obtain a permit from the Army Corps of Engineers before destroying a wetland to ensure environmentally responsible practices. The new regulations will eliminate the need for a federal permit to build over wetlands, allowing developers to act with minimal environmental oversight, according to Weltzer. 

EPA Administrator Lee Zeldin defended the move in a statement, arguing it “protects the nation’s navigable waters from pollution, advances cooperative federalism by empowering states, and will result in economic growth across the country.” Agricultural, chemical, and mining industry groups also celebrated the EPA’s push to curb federal water protections.

“The Supreme Court clearly ruled several years ago that the government overreached in its interpretation of what fell under federal guidelines,” read a statement from Zippy Duval, the American Farm Bureau Federation’s president. “We are still reviewing the entire rule, but we are pleased that it finally addresses those concerns and takes steps to provide much-needed clarity.”

When Europeans settled the area in the 1700s, Illinois was home to more than 8 million acres of wetlands. The state has since lost about 90 percent of that terrain to agriculture, development, and urbanization. Illinois’ wetlands alone provide $419 million worth of residential flood protection annually, according to the University of Illinois Urbana-Champaign. 

Since the Supreme Court decision gutted federal protections for wetlands, states like Colorado have passed their own laws to safeguard their endangered ecosystems. Illinois lawmakers have attempted to introduce similar legislation, but have yet to succeed. 

“The vast majority of Illinois wetlands do not have federal protection,” said Robert Hirschfeld, director of water policy at the Prairie Rivers Network. “The loss of the federal Clean Water Act means it is open season on wetlands.”

A recent study from the University of Illinois Urbana-Champaign found that slashing the wetland protection could endanger the vast majority of the state’s dwindling wetlands.

“We determined that about 72 percent of Illinois wetlands, which is about 700,000 acres, no longer meet that criteria for continuous surface connection to relatively permanent waters in Illinois,” said Chelsea Peters, a PhD candidate in wetland ecology at the University of Illinois and a lead author of the study. “So they are not protected by the Clean Water Act.”

That figure could get higher depending on how regulators hash out wetness requirements. “The next best estimate is 90 percent,” she said. 

The proposal still has a long road ahead before being finalized. The EPA has opened a 45-day comment period for the public to weigh in on the proposed change. The EPA will consider these public comments before finalizing rule changes as early as the first quarter of next year.

This story was originally published by Grist with the headline Illinois has few remaining wetlands. A Trump administration proposal could decimate what’s left. on Nov 24, 2025.