Contributed by Annie McIlwain P.E., Principal, PPM Consultants
Big changes are brewing over at the EPA. In a move that could reshape how we protect our waterways, the agency just announced its planning to revise the definition of “Waters of the United States” (WOTUS) under the Clean Water Act. If that phrase sounds dry (pun intended), stick with me—because it actually determines what kinds of streams, wetlands, ponds, and ditches the federal government can regulate. This new push comes in response to the 2023 Supreme Court ruling in Sackett v. EPA, which significantly narrowed the scope of waters eligible for federal protection. Now, the EPA is hitting the reset button and promising to work with stakeholders to come up with a version of WOTUS that’s, as they put it, “clear, simple, and enduring.”
For now, they’re guiding states to use the pre-2015 definition—but that’s no small change. The 2015 rule (also called the Clean Water Rule) had clarified that federal protections extended to streams and wetlands “with a significant nexus to navigable waters,” which included things like seasonal tributaries and isolated wetlands. The idea was to recognize how even small or temporary water bodies connect to larger ecosystems. But the Sackett ruling knocked out the “significant nexus” test, so the EPA has to find a new way forward.
The Clean Water Act of 1972 aimed to restore and maintain the integrity of the nation’s waters, but it left the term “navigable waters” vaguely defined. Over the years, the EPA and the U.S. Army Corps of Engineers have worked to clarify this through regulations and guidance. Key Supreme Court decisions, such as United States v. Riverside Bayview Homes (1985), Solid Waste Agency of Northern Cook County v. U.S. Army Corps of Engineers (2001), and Rapanos v. United States (2006), have influenced the interpretation of WOTUS, often leading to shifts in regulatory scope.
In 2015, the Obama administration introduced the Clean Water Rule to provide a clearer definition of WOTUS, extending protections to smaller streams and wetlands. However, this rule faced legal challenges and was repealed by the Trump administration, which replaced it with the Navigable Waters Protection Rule in 2020, narrowing the scope of federal water protections. The Biden administration later sought to restore broader protections, but the 2023 Sackett decision limited federal authority to waters with a continuous surface connection to navigable waters.
As the EPA gears up (again) to rewrite the WOTUS rule, all eyes are on what comes next—and let’s be honest, it’s going to be a political balancing act on a tightrope. The agency says it wants a definition that brings “clarity” for farmers, developers, and landowners while still protecting the nation’s waters. Sounds great on paper, but that balance is notoriously hard to strike. With Trump back in the driver’s seat of environmental policy, many are expecting the pendulum to swing hard in the direction of deregulation. Think: fewer wetlands under protection, more leeway for agriculture and real estate, and a serious scaling back of federal oversight.
I anticipate that we could see something similar to the 2020 Navigable Waters Protection Rule—Trump’s version of WOTUS—which ditched protections for ephemeral streams (those that only flow during rainfall) and isolated wetlands. That rule was praised by industry groups for “cutting red tape” and slammed by environmentalists who warned it opened the floodgates—literally—for pollution. If history repeats itself, we might be looking at a definition that prioritizes economic development over ecosystem connectivity. In the end, this rule won’t just decide what puddle counts as protected—it’ll shape the future of how we manage water, land use, and climate resilience across the country.
If you are curious what this could mean for your facility, please feel free to reach out to me at annie.mcilwain@ppmco.com. We are here to help!