Arizona is joining Nevada in a legal battle over the future of the Colorado River.
The Arizona Department of Water Resources announced on Friday that it has signed on to Nevada's lawsuit against the federal government over new Colorado River cuts.
The legal action comes after years of failed negotiations among seven Western states over how to divide the Colorado River's dwindling water supply.
In August, the federal government finalized a new operation plan that required Nevada, Arizona and California to reduce their water use, while imposing no mandatory reductions for the four "Upper Basin" states: Colorado, Utah, Wyoming and New Mexico.
Why did Nevada decide to sue? Southern Nevada Water Authority manager explains: Nevada sues feds over Colorado River cuts: 'We weren't looking for a fight'Officials in Nevada and now Arizona have argued that the Upper Basin states should also be required to contribute to conservation efforts mandated by the federal government. Nevada filed its lawsuit in August, challenging the process used to develop the new operating guidelines.
The Upper Basin states maintain that they already use less water when river flows decline and that their legal obligations differ from those of downstream states.
Arizonas decision to join our lawsuit is an important step in challenging a federal plan that unfairly burdens the Lower Basin and fails to require the Upper Basin to make meaningful reductions," Gov. Joe Lombardo wrote on Friday. "Nevada will not accept a framework that puts our water supply and the future of our communities at risk."
What does this mean for you?The outcome will have significant consequences for millions of people who rely on Colorado River water.
The lawsuit argues the federal government's new rules could cut up to 71% of Nevada's Colorado River water supply, threatening the water security of more than 2.3 million residents in the Las Vegas valley. Meanwhile, Nevada has already reduced its Colorado River water consumption by more than 40% since 2002 even as the Las Vegas valley's population grew by 875,000 people.
While the federal government's new operating framework took effect October 1, reductions to Arizona's water deliveries are scheduled to begin January 1, 2027.
Even deeper cuts remain possible in subsequent years under the federal government's 10-year framework. The legal dispute adds another layer of uncertainty as Nevada and its neighboring states work to secure a long-term agreement governing one of the West's most important water sources.
Experts warn Colorado River system is heading toward water bankruptcy
