The U.S. Supreme Court on Monday unanimously declined a petition by Imperial Valley farmer Michael Abatti claiming he and a handful of other agricultural landowners, not the Imperial Irrigation District, held senior rights to Colorado River water that nearly 40 million people across the West depend on.

The decision likely is the last stop for a torturous legal battle that dates back to 2013. As the law stands, farmers have a guaranteed right to water delivery but not a special claim above other users like homes and geothermal plants.