Colorado River cuts could drive up your water bill

Tucson residents are unlikely to see their taps run dry because of the newly finalized Colorado River water cuts, but they could feel the effects through higher water bills. Arizona is taking the largest reduction among the three Lower Basin states affected by the federal plan, and officials say large cities such as Tucson may need to raise rates as they pay more for supplies, conservation and other sources of water.

Under the agreement, Arizona will reduce its Colorado River use by 760,000 acre-feet from its current allocation of 2.8 million acre-feet for the next two years. California and Nevada will take the rest of a combined 1.25 million acre-foot reduction among the three states. Arizona’s share represents more than half of the total cuts in the Lower Basin, the region that includes Arizona, California and Nevada.

The reduction is part of an effort to keep the Colorado River’s two largest reservoirs, Lake Mead and Lake Powell, from falling toward levels where they could no longer produce hydropower. Federal officials finalized the plan after more than two years of negotiations among the states. The river serves more than 40 million people across seven states, several tribal nations and Mexico, while also supporting millions of acres of farmland. Decades of overuse, drought, rising temperatures and climate change have reduced the river’s flow below what planners expected when the system was designed.

For Tucson, the immediate outlook is more stable than the statewide numbers might suggest. Karl Flessa, a University of Arizona researcher who studies the river, said Tucson Water has stored at least six years of supplies, providing a buffer against the current reductions. He said residents should not expect an immediate household impact, meaning water should continue flowing normally from their faucets over the next two years. The cuts affect the system’s overall supplies and costs, rather than requiring Tucson households to suddenly receive less water.

That does not mean Tucson is insulated from the financial consequences. Patrick Dent, assistant general manager of water policy for the Central Arizona Project, said household water allocations are not expected to change in the short term, but water rates could rise in large municipalities such as Tucson. Cities throughout the Colorado River Basin are searching for replacement supplies, including groundwater, treated wastewater and desalination. Those options generally cost more than receiving water through the river system, and those expenses can eventually reach customers through utility rates.

Arizona’s vulnerability is tied in large part to its water rights. The Central Arizona Project, a network of canals serving the Phoenix and Tucson areas, was built later than some other major aqueducts. As a result, CAP has lower priority rights under the legal system governing the river, placing much of the state’s Colorado River supply near the front of the line for reductions. The federal plan’s longer-range framework suggests Arizona would continue absorbing the largest share of future cuts, a prospect that state officials and CAP leaders reject.

Arizona has warned that it could challenge the federal approach in court. State officials argue that the administration’s plan does not adequately follow the Colorado River Compact, the 1922 agreement that divided water among the states. Arizona Department of Water Resources Director Tom Buschatzke said the state does not accept a framework that would allow the federal government to choose among potentially severe reductions every two years over the coming decade. He has reserved Arizona’s right to seek relief in court, potentially sending the dispute to the U.S. Supreme Court.

The legal threat reflects a broader disagreement over who should bear the river’s losses. Arizona, California and Nevada have pushed for all seven states to make specific and measurable reductions. The Upper Basin states, Colorado, New Mexico, Utah and Wyoming, have argued that mandatory reductions to their water use could violate the existing compact. The finalized plan requires cuts in the Lower Basin for now, while the Upper Basin states may pursue voluntary reductions, mainly among agricultural users. Arizona officials say any reductions beyond the current two-year agreement should be shared across the basin and should come from existing uses.

The stakes are high for farms, cities and tribes. Arizona and Nevada have faced mandatory reductions before, but the new plan is deeper. Agriculture in Yuma and Southern California supplies much of North America’s winter leafy greens, and reduced water deliveries could leave fields unplanted or increase reliance on groundwater. Arizona’s water officials have described the possible effects on users and the economy as severe. At the same time, the river’s long-term condition is worsening. Its average flow since 2020 has been 32% below the 20th century average, and this year the Rocky Mountains recorded their lowest snowpack on record. Researchers say higher temperatures account for roughly half of the river’s decline, with flow expected to drop further as the Southwest warms.

The current agreement lasts only through 2028, making the next phase of negotiations especially important for Tucson and the rest of Arizona. Dent said discussions over the rules that will follow should begin soon because the existing deal took years to complete. Flessa said Tucson and other Arizona communities need to accelerate conservation, water recycling and purification projects, including systems that could eventually produce drinking water from treated wastewater. The immediate message for residents is that the new cuts are not expected to change everyday access to water, but the cost of maintaining that reliability, and the consequences of failing to reach a broader agreement, are likely to become more visible in future water bills and policy debates.