Politics
Arizona backs Nevada challenge to federal Colorado River rules
Arizona is joining Nevada’s lawsuit challenging the federal framework for managing the Colorado River after 2026. The states say the plan puts too much of the burden on the Lower Basin and was developed through a flawed environmental review process.
Arizona will join Nevada’s lawsuit challenging the federal government’s plan for Colorado River operations after 2026, the state announced Oct. 16, 2026. The legal challenge disputes how the federal framework was developed and how it would divide water-reduction responsibilities among the basin states.
Nevada Gov. Joe Lombardo welcomed Arizona’s decision, arguing that the plan places an unfair burden on the Lower Basin while failing to require substantial cuts from the Upper Basin. He said Nevada would continue to pursue a negotiated agreement but would oppose a framework that he believes risks the state’s water supply and communities.
John Entsminger, general manager of the Southern Nevada Water Authority, said Arizona and Nevada share concerns about the federal Environmental Impact Statement and the process under the National Environmental Policy Act. He said decisions affecting the river should follow a transparent, science-based and legally sound process.
Entsminger also said the water authority remains committed to working with Arizona and California on an agreement to reduce near-term demands on Lake Mead. He said cooperation among the Lower Basin states could help support a broader, lasting agreement among all seven Colorado River Basin states.
The dispute comes as federal officials set out rules for river operations after 2026, when the current operating guidelines expire. The Colorado River supplies water to communities, farms and economies across the West, making negotiations over how to share shortages consequential for states throughout the basin.