A federal judge in North Dakota on Wednesday blocked in 24 states the Biden administration’s newly effective definition of waters that can be regulated under the Clean Water Act.

U.S. District Judge Daniel Hovland, a George W. Bush appointee on retired status in the North Dakota District, issued a preliminary injunction in a case two dozen Republican state attorneys general brought against the U.S. Environmental Protection Agency and the Army Corps of Engineers.

The ruling for now blocks enforcement of a rule to expand what the EPA could consider “waters of the United States,” or WOT...