Nevada Sues Over Colorado River Plan as Arizona Weighs Its Own Legal Action

Nevada has sued the Trump administration over a newly finalized federal plan for managing Colorado River water through 2028, becoming the first state to challenge the deal in court. Arizona, which takes the deepest cuts of any state under the plan — 760,000 acre-feet, or roughly 250 billion gallons, per year — is reviewing the lawsuit and has publicly reserved the right to file its own legal challenge.

What does the finalized plan actually require?

The U.S. Department of the Interior’s Record of Decision, released Friday, August 21, adopts a water-sharing agreement negotiated jointly by Arizona, California and Nevada rather than imposing cuts unilaterally from Washington. Federal officials stepped in because the seven states that draw from the river — Arizona, California, Nevada, Colorado, New Mexico, Utah and Wyoming — could not agree on collective reductions, even as the river’s two largest reservoirs sit at record-low levels. Under the plan, Colorado, New Mexico, Utah and Wyoming give up no water at all. Arizona, California and Nevada absorb cuts, with Arizona taking the largest share: about a 30% reduction to its overall Colorado River allocation, and a 50% cut specifically to water delivered by the Central Arizona Project (CAP), the canal system that supplies the Phoenix and Tucson metro areas.

Why is Nevada suing, and does Arizona agree with the complaint?

Rhett Larson, a water law professor at Arizona State University, said Nevada’s lawsuit is less about stopping the next two years of cuts and more about forcing the federal government to follow proper environmental review procedures — the National Environmental Policy Act (NEPA) process — in how it reached the plan. He said Arizona “shares many of the exact same concerns” and similar motivations. Tom Buschatzke, director of the Arizona Department of Water Resources, said at a virtual press conference that the state is “reserving our right to potentially take legal action to protect our rights,” covering both the current two-year plan and the following decade. A department spokesperson said Monday that Arizona is “evaluating Nevada’s complaint” before deciding how to proceed. CAP itself has said the post-2028 framework contains conditions it “will not accept,” calling it a violation of the legal framework governing the river — known as the Law of the River — that would impose “disproportionate, unlawful, and intolerable cuts” on Arizona.

Could a lawsuit actually stop the cuts?

Larson said it’s possible a court could pause the cuts while litigation proceeds, but he thinks that’s unlikely — resolving the case fully would take longer than the time remaining before the new water year starts in October. He suggested the more realistic target of any legal fight is the longer-term river management framework covering the next ten-plus years, not the immediate two-year plan.

How is Arizona coping with the cuts on the ground?

State officials say the plan avoided the worst-case scenario that had threatened even steeper reductions, and that it shouldn’t affect residents’ ability to get water from the tap. But impacts vary sharply by city depending on how reliant each is on CAP water: Cave Creek gets about 95% of its water from the Colorado River through CAP, one of the highest rates in the state, compared with 70% for Scottsdale and 40% for Phoenix. Phoenix deputy water services director Max Wilson said the city has spent a decade preparing and will lean on backup supplies, including expanded dam capacity on the Salt and Verde rivers. Cave Creek water consultant Brad Hill said the town is pursuing short-term water exchange agreements — roughly seven-year “bridge supplies” — to buy time while it develops more expensive long-term solutions. Larson said the region isn’t running out of water outright but is “running out of cheap water,” pointing to rising bills; Gilbert has already raised residential water rates 50% since April 2025. Sarah Porter of ASU’s Kyl Center for Water Policy said cities and towns vary widely in how prepared they are.

What is Arizona doing to find new water supplies?

Separately, Arizona is pursuing two long-shot projects aimed at bringing up to 200,000 acre-feet of new water into the state annually, both backed by a subsidiary of the Canadian firm EPCOR. One would capture up to 100,000 acre-feet a year of floodwater from California’s Sacramento and San Joaquin rivers, route it through the California Aqueduct into Central Valley groundwater storage, and eventually give Arizona rights to Colorado River water otherwise held by Southern California agencies. The other would study treating wastewater — largely sewage from Tijuana, Mexico — near San Diego to drinking-water standards, sending it back to Mexico for municipal use in exchange for Arizona gaining rights to up to 100,000 acre-feet of Mexico’s Colorado River allocation. The Arizona Water Infrastructure Finance Authority board approved $7.3 million to study the two projects, with up to five more proposals, including three desalination plants, possibly getting initial funding next month. Reactions from California water officials are mixed: Kern County Water Agency general manager Eric Averett, who hadn’t heard of the Arizona proposals, called the sewage-treatment swap “creative and doable,” while an unnamed environmentalist described the floodwater-capture plan as “somewhat delusional.”

Sources

• AZFamily — Lawsuit filed over plan for Colorado River where Arizona is set to take deep cuts · Arizona sees largest Colorado River cuts under new federal water deal
• Arizona Capitol Times

Featured photo: NASA, USGS via Wikimedia Commons (Public domain)