When it comes to the Colorado River, a court battle between the states that use its water is sometimes referred to as “the nuclear option.” But now, as those states are locked in disagreement about how to share its water, they are tiptoeing closer toward litigation.
State leaders insist they want to avoid a trip to the Supreme Court, but some are quietly preparing for that outcome.
The Colorado River supplies water to about 40 million people from Wyoming to Mexico . C limate change is shrinking its supplies. The cities and farms that use it are under pressure to rein in demand accordingly.
Water managers from the seven states that use the Colorado River are caught in a standoff about who exactly should use less water, and they appear to have made little progress ahead of a 2026 deadline for new rules about how to share.
In January, Arizona’s government made headlines when a proposed state budget included up to $3 million for litigation related to the Colorado River.
“It's really a backstop in case we don't come to a collaborative agreement,” said Tom Buschatzke, Arizona’s top water negotiator.
Buschatzke described the litigation fund as a contingency plan and said state leaders were focused on collaborating.
“I think each state honestly does not want to be in a courtroom rolling the dice regarding how a judge might rule,” he said.
For all of their differences, the two sides of the current Colorado River dispute seem to agree on one central issue: they want to keep their debate out of the Supreme Court. That appears to be the case in the Lower Basin states of Arizona, California and Nevada, as well as the states on the other side of the disagreement — the Upper Basin states of Colorado, Utah, Wyoming and New Mexico.
“We are the ones who should really shape the outcome here,” said Amy Haas, executive director of the Colorado River Authority of Utah. “We're the experts. We're the water managers. We understand the system. Why would we want to relinquish that control and that responsibility?”
She said Utah would prefer to spend its money on avoiding a court battle rather than preparing for one.
“I think it would be folly for us to pursue a litigated outcome here,” Haas said.
An overwhelming majority of Colorado River policymakers — including Arizona’s — say they’d prefer to work amongst themselves instead of getting the federal government involved. Why, then, would Arizona make a show of its proposed litigation fund?
Some onlookers say it’s a negotiation tactic.
“This is definitely a posturing issue,” said Gage Hart Zobell, a Utah-based water lawyer with the firm Dorsey & Whitney. “I think a lot of what we see is the Lower Basin is trying to make it very clear they are willing and open to litigate this issue because they think they have the higher hand.”
Buschatzke outright denied that the litigation fund was a form of posturing, but Hart Zobell said there’s a financial reality that suggests Arizona’s move is a form of saber-rattling.
“In the event litigation does go forward,” he said. “You don't have to build a litigation fund to come up with $5 million. Any state budget can come up with $1 million, $2 million, $3 million to fight this.”
Hart Zobell pointed to a recent Supreme Court case that helps give some clues as to how the Colorado River debate might get settled if it heads there. The 2024 case “Texas v. New Mexico” brought tensions over another Southwestern river, the Rio Grande, to the high court. The case gave the federal government more leverage in talks about managing that river’s water.
“Under the new Supreme Court precedent, if we get into a lawsuit, they have a right to intervene,” Hart Zobell said . “ Once they're in, we're not just having Upper and Lower Basin discussing. We've got a third party that we've got to settle with.”
So Arizona’s litigation fund, Hart Zobell said, it may be a way to remind other states of the consequences if they don’t come to an agreement amongst themselves.
“I think that looming specter is really going to push the states a lot more to finding some negotiated settlement,” he said . “Because if the federal government does intervene, I don't think any state is going to get what it wants.”
Arizona’s Buschatzke said that other states, such as New Mexico, Wyoming, and Colorado were also preparing money for Colorado River litigation.
KUNC reached out to each of the seven states that use the Colorado River. Arizona was the only one that indicated it had a specific pool of money for Colorado River work.
A spokeswoman for Colorado’s negotiating team pointed to a “long-standing litigation fund” that could be used for the Colorado River, and a division of the Colorado Attorney General’s office that has been focused specifically on the Colorado River since 2006.
New Mexico and Wyoming’s top water offices declined to comment for this story. The Upper Colorado River Commission, a group that brings together water leaders from Colorado, Utah, New Mexico and Wyoming said that it was not preparing a litigation fund.
The Colorado River basin is also home to 30 federally recognized Native American tribes. Although Indigenous people in the Southwest have been using Colorado River water longer than any other group in the region, they have largely been excluded from discussions about how the river is shared. Tribes that use the river control about a quarter of its flow, but most lack the money and infrastructure to use their full allotments.
Jay Weiner, water counsel for the Quechan Indian Tribe of the Fort Yuma Indian Reservation, said that is likely to add another layer to any legal battle over water.
“There is no version of this that you do not have tribes seeking to intervene in this litigation,” he said . “Or potentially seeking to bring their own claims as part of whatever food fight that the states end up in the Supreme Court over.”
Whether the states settle their differences amongst themselves or in court, they will be forced to reckon with a water supply that has been significantly reshaped by climate change. More than two decades of dry conditions have forced the states into tough conversations about using less water across the farms and cities of the arid West.
“It is very, very hard to ask people to agree to sign up to make hypothetical future sacrifices of bone-cutting magnitude,” Weiner said.
Some state leaders have indicated that the threat of litigation might actually help them make those sacrifices. At a 2023 conference about water law, Nevada’s top water negotiator John Entsminger said the “federal anvil” hanging over the basin states was key to finding agreement during other contentious water-sharing talks over the past two decades.
This story is part of ongoing coverage of water in the West, produced by KUNC in Colorado and supported by the Walton Family Foundation. KUNC is solely responsible for its editorial coverage.
Copyright 2025 KUNC