In a unanimous vote, the Supreme Court ruled on Thursday that the EPA had overstepped its authority with its attempt to massively expand its regulatory scope under the Clean Water Act.

The Court unanimously ruled for the plaintiffs in the case, styled Sackett v. EPA, who had challenged the agency’s ruling they could not make productive use of property they purchased decades ago using a rationale that would vastly expand the law’s original intent. As written, the Clean Water Act allows EPA to regulate the “navigable waters of the United States,” a term that had, prior to the agency’s overreach in the Sackett case, been held to mean a body of water that could be navigated by a vessel. 

For the last 17 years, the Sackett family has been entangled with the agency over some patches of sporadic wetlands that appear on their property during rainy seasons, which the EPA wishes to regulate under this “navigable body of water” clause. Writing for the majority in a more narrowly-divided concurring decision that will now govern the specific allowable interpretation of the law, Justice Samuel Alito holds that only wetlands that are “indistinguishable” from larger nearby bodies of water can be regulated under the Clean Water Act. 

“Wetlands that are separate from traditional navigable waters cannot be considered part of those waters, even if they are located nearby,” Alito wrote.