A California federal judge is weighing whether to block the Trump administration’s controversial water rule, as requested by more than a dozen states suing over the regulation.

The U.S. District Court for the Northern District of California spent three hours Thursday hearing arguments on whether to halt the Navigable Waters Protection Rule from taking effect on June 22, as planned.

A preliminary injunction will “prevent widespread harm to national water quality, and disruption” to water pollution control in cities and states while the claim is litigated, the 17-state coalition led by California and New York argued in a motion filed last month.

The rule “seriously undermines water quality and seriously is contrary” to the Clean Water Act, New York attorney Timothy L. Hoffman, representing the coalition, told Judge Richard Seeborg.