Supreme Court limits the EPA’s authority under the Clean Water Act

Enlarge / Wetlands like this may end up a complicated patchwork of regulated and unregulated areas thanks to the latest Supreme Court decision. (credit: Stefano Madrigali)

On Thursday, the US Supreme Court issued a ruling that severely limits the EPA's ability to regulate pollution under the Clean Water Act. The ruling applies to wetlands that are connected to bodies of water that fall under the Clean Water Act's regulatory scheme, with the court now ruling that those connections need to be direct and contiguous in order for the act to apply. This would remove many wetlands that are separated by small strips of land—including artificial structures like levees—from oversight by the EPA.

The decision is a somewhat unusual one, in that all nine justices agree that the people who originally sued the EPA should prevail. But there was a very sharply worded 5-4 disagreement over what the word "adjacent" means.

Whose waters are these?

The Clean Water Act was a major piece of environmental regulation, put in place due to the sometimes horrific pollution prevalent in the early 1970s. Its text applies regulations to the "waters of the United States," a term that has proven sufficiently vague that it has been the subject of a variety of lawsuits and federal regulatory policies over the years. A number of geographic features—seasonal streams, human-made water features, and marshlands without a direct connection to rivers—have all been subject to dispute.