Arizona has joined neighboring Nevada in legal action against the federal government over a controversial 10-year water management plan that imposes major cutbacks across the Southwest. Tom Buschatzke, director of the Arizona Department of Water Resources, announced Friday that the state filed a motion to intervene in the ongoing lawsuit initiated by Nevada.
Nevada originally filed its lawsuit in August to challenge the federal plan, arguing that shrinking water allocations would devastate Las Vegas and surrounding municipalities. Buschatzke echoed those concerns for his state, stating that the mandatory reductions outlined in the federal blueprint “would devastate Arizona’s economy.”
The expanding legal confrontation could ultimately reach the U.S. Supreme Court, threatening to further complicate negotiations among seven western states striving to establish a sustainable framework for sharing water from the rapidly depleting river system and its reservoirs.
In recent years, Arizona has relied on the Colorado River for 36 percent of its water supply, much of which is transported via the Central Arizona Project—a vast network of canals stretching from the river to the Phoenix and Tucson metropolitan regions. Under the challenged federal plan, much or all of the water delivered through the Central Arizona Project could face severe slashes. Because the canal system is relatively young compared to other regional aqueducts, it holds low-priority water rights, making it one of the first in line for reductions.
The Colorado River supplies water to approximately 35 million people across cities ranging from Denver to San Diego, alongside 30 Native tribes. Furthermore, about three-fourths of the water withdrawn from the river supports roughly 5 million acres of farmland, producing alfalfa for livestock as well as lettuce, broccoli, and other crops. Severe pressures on the system have mounted as the Rocky Mountains recorded their lowest snowpack on record this year, with the resulting deficit in snowmelt driving reservoir levels even lower.
Negotiators have held repeated talks over the past three years attempting to forge a seven-year agreement among all seven states to reduce consumption, but the three downstream states—California, Arizona, and Nevada—have remained deadlocked with the four upstream states of Colorado, Utah, New Mexico, and Wyoming.
Arizona, Nevada, and California have previously agreed with the federal government on interim cuts for a two-year horizon, planning to reduce water usage by 3.2 million acre-feet between now and the end of 2028. During this period, California is set to cut its Colorado River water consumption by approximately 12 percent, while Arizona will reduce its intake by about 31 percent and Nevada by 28 percent. Buschatzke noted that Arizona remains strongly committed to this interim agreement and is currently engaged in talks to finalize its details.
The core objection from the downstream states centers on the federal plan’s failure to require water reductions from Colorado, Utah, New Mexico, and Wyoming. Arizona Governor Katie Hobbs criticized the federal approach, stating that she would not accept a forced federal plan that resolves the crisis entirely on the backs of local families, farmers, and businesses.
“We are drawing a line in the sand,” Hobbs said, adding that the state took legal action because the federal government refuses to hold upstream states accountable for the water deliveries owed to Arizona while threatening draconian cuts.
Nevada Governor Joe Lombardo expressed support for his neighbor’s decision to join the litigation. Both states strongly object to the prospect of enduring much deeper cuts after 2028. The federal framework permits drastic water reductions between 2029 and 2036 if deemed necessary, potentially forcing the three downstream states to slash 3 million acre-feet per year—amounting to as much as 40 percent of their total allocation.
Buschatzke warned that the federal decision places the entire burden of sacrifice on three states, noting that such reductions could effectively dry up the Central Arizona Project. Meanwhile, California, which consumes more Colorado River water than any other state, has not indicated any plans to join the lawsuit.
Decades of persistent drought intensified by climate change have steadily diminished the river’s flow and severely depleted its major storage basins. Both Lake Mead and Lake Powell, the nation’s largest reservoirs, have dropped to unprecedented lows. Arizona officials had previously warned federal authorities that further declines in water flowing into Lake Mead would trigger the state’s right to sue for violations of the 1922 Colorado River Compact, a century-old agreement that divided the river’s water among the basin states and mandates that water released from upstream dams average at least 7.5 million acre-feet over any decade, in addition to allotments for Mexico.
