The Biden administration had already said it plans to repeal the Trump-era rule and issue new regulations defining which waterways are federally protected under the Clean Water Act. But the Trump rule remained in place in the meantime, and environmental groups, Native American tribes and others said it could lead to the loss of wetlands, damage wildlife habitat and allow businesses and farmers to pollute waterways.

U.S. District Court Judge Rosemary Marquez in Arizona, an Obama appointee, sided with those groups on Monday, determining that the Trump administration’s rule last year improperly limited the scope of clean water protections. Marquez said the Environmental Protection Agency had ignored its own findings that small waterways can affect the well-being of the larger waterways they flow into.

The EPA, now headed by Biden appointee Michael Regan, said it is reviewing the decision and declined to comment. In June, Regan said the agency planned to issue a new rule that protects water quality while not overly burdening small farmers.

The water rule — sometimes called “waters of the United States” or WOTUS — has long been a point of contention. In 2015, the Obama administration expanded federal protection to nearly 60% of the nation’s waterways. Because the Obama rule also faced several legal challenges, Monday’s decision puts back in place a 1986 standard — which is broader in scope than the Trump rule but narrower than Obama’s — until new regulations are issued.

Read more about the rollback of clean water rules