Arizona is poised to shoulder the largest share of Colorado River water cuts under new federal operating guidelines designed to stabilize a river system pushed to historic lows by more than two decades of drought.
The U.S. Department of the Interior’s 2027-2028 Operating Guidelines call for 1.25 million acre-feet of annual reductions in Colorado River use among the Lower Basin states of Arizona, California and Nevada. Under the plan, Arizona’s allocation would be reduced by 760,000 acre-feet annually, compared with 440,000 acre-feet for California and 50,000 acre-feet for Nevada.
For perspective, the Arizona Department of Water Resources estimates that one acre-foot can supply roughly three Phoenix-area homes for a year.
The Colorado River cuts come amid increasingly dire conditions on the Colorado River. According to the Bureau of Reclamation, the basin has endured 26 years of unprecedented drought, and a record-low snowpack during the winter of 2025-2026 pushed combined storage in Lake Mead and Lake Powell below any level seen since before Lake Powell began filling in 1963. Both reservoirs reached record-low elevations in August 2026.
The federal guidelines also call for at least 700,000 acre-feet of additional system conservation in Lake Mead through 2028.
The plan, however, is drawing criticism from Arizona water leaders.
“Today we also heard from the federal government that our major reservoirs, Lake Mead and Lake Powell, are in crisis,” said Brenda Burman, Central Arizona Project general manager. “Both lakes are in Arizona, and we want them both healthy for our communities. But the framework presented is flawed. Lake Mead should not be sacrificed to protect Lake Powell or other Upper Basin reservoirs, and every state that relies on the river should be part of the solution. The Colorado River needs to be treated as the system it is.”
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What the cuts mean for Arizona
Despite the size of Arizona’s Colorado River cuts, most Phoenix- and Tucson-area residents are unlikely to see immediate changes when they turn on their faucets.
Central Arizona water providers have spent years preparing for deeper Colorado River shortages by developing backup supplies, storing water underground and creating transfers and exchange agreements. Some communities can also rely on Salt and Verde river supplies.
The new rules are nevertheless significant for Arizona because the Colorado River remains a critical water source for municipalities, agriculture, tribes and businesses across the state.
The federal government’s intervention follows years of negotiations among the seven Colorado River Basin states — Arizona, California, Nevada, Colorado, New Mexico, Utah and Wyoming — that failed to produce consensus on long-term operating rules.
Instead, the Interior Department will implement a two-year operating interval beginning Oct. 1 as part of a broader 10-year Decision Framework running through 2036. The framework anticipates new operating guidelines generally every two years unless the states reach a longer-term consensus agreement.
Protecting Lake Powell — and Lake Mead
One of the federal government’s priorities is preventing Lake Powell from falling to elevations that threaten critical infrastructure and hydropower generation.
The new guidelines establish three elevation ranges for Lake Powell, with annual releases generally ranging from 6 million to 8.23 million acre-feet. Initial releases will be selected with the goal of keeping Powell above 3,510 feet. Under certain conditions, releases could fall as low as 5 million acre-feet, accompanied by water released from upstream Colorado River Storage Project reservoirs.
For Lake Mead, additional consultation would be triggered if projections show the reservoir falling below 1,010 feet. Deliveries of certain stored water would face additional restrictions at 1,025 feet and would be prohibited below 1,000 feet.
Those thresholds underscore the severity of a challenge that has been building for decades: The Colorado River simply has less water flowing into its reservoirs while demand continues to strain the system.
For Arizona, the next two years represent both a major test of years of water-planning efforts and another reminder that the Colorado River’s long-term future remains unsettled. The federal framework gives the seven states more opportunities to negotiate — but after years of deadlock, reaching an agreement that spreads the pain across the entire basin may be the biggest challenge yet.
