The US Supreme Court ruled Thursday that wetlands must be adjacent to and “indistinguishable” from protected waters in order to qualify for protection under the Clean Water Act (CWA). Delivering a decision in Sackett v. EPA, the Court sided with the appellants, prioritizing the rights of wetland owners whose property is not adjacent to protected waters. Ultimately, the ruling hinders the Environmental Protection Agency’s (EPA) ability to protect wetlands via the CWA.

In the majority opinion, the Court laid out a new test to determine whether a wetland qualifies for protection under the CWA. Previously, the Court of Appeals for the Ninth Circuit applied reasoning advanced by Justice Kennedy’s concurrence in Rapanos v. United States, finding that Sackett’s wetlands were subject to EPA regulations because they had a “significant nexus [with] navigable waters.” However, Thursday’s decision rejected this test and instead adopted the one used by the plurality in Rapanos. 

Writing for the court, Justice Alito said:

[Covered] “waters” may fairly be read to include only those wetlands that are “as a practical matter indistinguishable from waters of the United States,” such that it is “difficult to determine where the ‘water’ ends and the ‘wetland’ begins.” That occurs when wetlands have a “continuous surface connection to bodies that are ‘waters of the United States’ in their own right, so that there is no clear demarcation between ‘waters’ and wetlands.”

However, Justice Kavanaugh wrote a concurring opinion in which he joined the court’s judgment but disagreed with the new test. Kavanaugh’s concurrence was joined by Justices Sotomayor, Kagan and Jackson. Kavanaugh agreed with reversing the Ninth Circuit’s judgment and “significant nexus” test, but said that “the Court’s ‘continuous surface connection’ test departs from the statutory text, from 45 years of consistent agency practice, and from this Court’s precedents.”

With the Court’s new stringent test set as legal precedent for future regulations, several environmental groups have expressed disappointment in Thursday’s decision. According to a statement from Sierra Club Executive Director Ben Jealous, “American people deserve better than having their clean water sold to the highest bidder.” In a tweet, the Natural Resources Defense Council said “today’s Supreme Court ruling puts people and vulnerable communities in harm’s way.” EPA Administrator Michael S. Regan also issued a statement expressing his disappointment with the decision.

Thursday’s ruling comes after President Joe Biden expanded the definition of “waters of the United States” in an attempt to increase environmental protections.