The U.S. Bureau of Reclamation released a federal proposal on Friday aimed at reducing water usage from the Colorado River among several western states to address severe shortages exacerbated by prolonged drought and climate change. Under the plan, Arizona, California, and Nevada—collectively known as the Lower Basin states—could face mandatory cuts totaling up to 3 million acre-feet annually through 2036, a volume roughly equivalent to the combined current allocations for Arizona and Nevada and sufficient to serve more than 25 million people.

The proposal is designed to be flexible, with adjustments every two years based on hydrological conditions affecting key reservoirs Lake Mead and Lake Powell. Both reservoirs have dropped to historic lows, threatening the river system’s ability to provide water and generate hydropower. The plan calls for cities and agricultural users in the Lower Basin to reduce consumption, with the specifics of how cuts are divided largely left to the states to work out, although federal officials are expected to offer guidance.

Interior Secretary Doug Burgum emphasized the government’s responsibility to maintain the Colorado River’s reliability for millions of Americans, while acknowledging the difficult trade-offs involved. The proposal spares the Upper Basin states—Colorado, Utah, Wyoming, and New Mexico—from mandatory cuts but encourages voluntary reductions primarily among agricultural users there.

Reactions among the states have been mixed. Arizona officials sharply criticized the plan, warning that it disproportionately burdens their state, which holds some of the lowest priority water rights in the system. Tom Buschatzke, director of the Arizona Department of Water Resources, described the potential impacts as “draconian” and detrimental to the state's economy and water users. The Central Arizona Project, the major water manager supplying metro Phoenix and Tucson, also contested the proposal’s portrayal of Arizona’s water rights.

Phoenix Mayor Kate Gallego expressed preparedness to reduce water use but opposed what she described as unfair expectations placed on Arizona. California viewed the plan as an important milestone but maintained it is not the final solution. Nevada had no immediate public response.

Experts noted that while cities in the basin may maintain water service in the near term, reductions could lead to increased water costs, greater reliance on groundwater, and fallowed farmland, particularly affecting agricultural zones that produce significant portions of the nation’s winter leafy greens.

Legal tensions loom as Arizona officials have indicated a willingness to challenge the plan in court, potentially escalating the dispute to the Supreme Court. The conflicts over water rights and allocations have deep historic roots, with many rights established almost a century and a half ago under the 1922 Colorado River Compact.

The federal plan also addresses international implications, since northern Mexico relies on water from the river, and negotiations with Mexico continue separately. The proposal allows for ongoing two-year reviews of water allocation rules, aiming to foster consensus among the seven basin states, though concerns persist that it may increase tensions.

With over 40 million people depending on the Colorado River for drinking water, agricultural irrigation of 5.5 million acres, and hydropower generation, the coming years are expected to be challenging as states and stakeholders negotiate how to equitably share diminishing water supplies in a changing climate.