Arizona Joins Nevada Lawsuit Over Colorado River Cuts

Arizona has moved to join Nevada’s lawsuit challenging the federal government’s post-2026 Colorado River operating plan, arguing that its environmental review is flawed and that the plan unfairly places mandatory water cuts on Lower Basin states while requiring none from the Upper Basin. Arizona says it wants federal enforcement of water-delivery obligations to Lake Mead and protection of its legal water rights; officials warn the plan could sharply reduce supplies, including water delivered through the Central Arizona Project, with serious consequences for the state’s economy. The legal challenge comes amid years of stalled negotiations over the river’s declining supply, though Arizona says it will continue working with Nevada and California on a Lower Basin conservation agreement for 2027 and 2028. Upper Basin states maintain that their water use already falls when river flows decline and that their legal obligations differ, leaving the dispute—and efforts to reach a seven-state agreement—unresolved.