Phoenix and Denver Brace for Colorado River Cuts, Seek Innovative Water Solutions
As the Colorado River shrinks under a prolonged drought, cities across the West are scrambling to secure their water future. Phoenix, facing potential cuts as early as January 2027, and Denver, proactively building resilience, exemplify the challenges and innovative strategies unfolding across the basin.
The sprawling Phoenix metro area and the Denver metropolitan region are on the front lines of a looming water crisis. Both cities, geographically distant from the Colorado River’s main stem, rely on extensive networks of canals and pipelines to deliver water to millions of residents. However, the future of that supply is increasingly uncertain as states struggle to agree on how to manage the dwindling resource.
Federal and state officials missed a November 11 deadline to finalize a joint agreement on reservoir operations beyond 2026, leaving communities throughout the basin in a state of anxious anticipation. “We’re doing quite a bit of scenario planning right now, trying just to game out what the range of possibilities could be,” said a water resources management advisor for the city of Phoenix. “Because we don’t know what the outcomes are, we’re developing many plans, but not perfecting any one of them.”
Phoenix is particularly vulnerable. The city receives 40% of its water supply through the Central Arizona Project (CAP), a 336-mile canal system authorized in 1968. However, CAP holds “junior” water rights, meaning it’s among the first to face cuts when the river runs low. Under some proposals, Arizona could experience cuts of up to 760,000 acre-feet in the driest years – an amount roughly equivalent to the annual water use of 2 to 4 million households.
“What it means at a core level, for many Valley cities and for Phoenix, is that we will need to rely on backup supplies to a much larger extent than we currently do today,” the Phoenix advisor explained.
Denver, while also facing long-term challenges, currently enjoys a more diversified water portfolio. Denver Water, serving 1.5 million residents, draws from mountain reservoirs and tributaries of the Colorado River, accounting for roughly half of its supply. The city also utilizes the South Platte River Basin, a separate watershed on the eastern side of the Continental Divide. However, Colorado as a whole faces a potential supply gap of up to 740,000 acre-feet in the driest years, according to the 2023 Colorado Water Plan.
“Shortages on the Colorado River could affect every water user and everyone’s water rights,” Denver Water stated. “That’s why we need storage to take advantage of wet years and be better prepared for drier ones.”
Both cities are actively pursuing innovative solutions. Denver is focused on removing thirsty grass and expanding reservoir capacity, while Phoenix is investing heavily in advanced water treatment technologies. In Phoenix, a noticeable shift in landscaping is already visible, with newer suburbs favoring desert-friendly designs over traditional lawns.
A key strategy for Arizona is direct potable reuse, an intensive treatment process that transforms wastewater into clean, drinkable water. Scottsdale already operates a permanent advanced water treatment facility, and Phoenix plans to bring three such plants online by 2028, potentially delivering up to 77 million gallons of purified water per day – roughly 30% of the city’s total needs. Colorado adopted regulations allowing this type of water reuse in 2023.
Beyond technological solutions, both cities are emphasizing conservation. Denver has reduced per capita water use by 36% since 2000 through conservation programs and efficient fixtures. Arizona communities, operating within “active management areas,” are required to demonstrate sufficient water supplies for the next 100 years.
Despite these efforts, uncertainty remains. City water managers urgently need clarity on potential cuts before October, when they submit water orders to the Central Arizona Project. A federal call in 2022 for a 2 to 4 million acre-foot reduction in demand across the basin underscores the scale of the challenge.
“We just really urge everybody to do what it takes, to have the humility to come and make the type of deal, that would be necessary to bring that demand reduction needed to stabilize the basin,” the Phoenix advisor urged.
Ultimately, the future of water in the West hinges on collaboration, innovation, and a willingness to adapt. As one official noted, the question isn’t whether cities like Phoenix can exist in the desert, but whether they will make the necessary choices to ensure a sustainable future. “We’re really confident here in Phoenix that we can be not just a sustainable desert city, but a sustainable city,” the advisor concluded, “One of the most sustainable cities in the world.”
