It is one of the first questions people ask before they move to Tucson, and the news this year has made it a fair one: the Colorado River, which supplies much of Arizona's water, is being cut again. Here is what was actually decided, who in Arizona takes the cut, where Tucson stands, and what to check about water on a particular home. Every figure is from the federal, state or city source linked beside it.
What was decided in August
On August 21, 2026, the Interior Department signed its decision on how the Colorado River will be run after 2026, with operating guidelines for 2027 and 2028 (U.S. Bureau of Reclamation). Under them, the three Lower Basin states share 6.25 million acre-feet a year in 2027 and 2028, 1.25 million less than normal. Arizona's share is 2.04 million acre-feet, a cut of 760,000 acre-feet a year; California gives up 440,000 and Nevada 50,000 (2027–2028 Operating Guidelines). That split depends on the states signing an agreement to share the reduction; if they do not, the Secretary of the Interior decides it.
Lake Mead stood at 1,039 feet in late August, with the whole river system 32 percent full, and Arizona has committed to conserve another 300,000 acre-feet voluntarily over 2026 to 2028 (Central Arizona Project). The decision is also in court: Nevada sued the Interior Department in August, and the Central Arizona Project itself has joined the litigation (CAP). So the headline number is real, but some of the details are not final.
Who takes the cut in Arizona
Central and southern Arizona get their Colorado River water through the Central Arizona Project's canal, and its water is delivered in order of priority. In CAP's preliminary analysis, which it labels illustrative, a 760,000 acre-foot reduction eliminates the agricultural pool and other excess water entirely, while cities' and industries' municipal priority is cut by about 14 percent (CAP). The state's water bank has extended its backstop for cities' CAP water through 2027, provided the Lower Basin states agree to share the reductions (Arizona Water Banking Authority). In other words, farms that rely on CAP water are hit first and hardest; cities are cut, but by much less.
Where Tucson stands
Tucson's CAP allocation is just over 144,000 acre-feet a year, and the city stores about a third of it underground each year rather than using it (Tucson Water), recharging it into the aquifer west and south of town for dry years. In September the city announced up to $125 million in federal funding to expand one of those recharge projects, in the Avra Valley, from 75,000 to as much as 140,000 acre-feet a year of storage by federal fiscal year 2032 (City of Tucson).
"The City's water supply remains resilient for the long term." (City of Tucson, July 31, 2026, adding that the federal assumptions do not establish Tucson's final Colorado River reduction)
The city has been at Tier 2 of its drought plan since 2023. Tier 3 would be triggered if Lake Mead fell below 1,025 feet, or if CAP deliveries became smaller than the city's yearly demand for drinking water (Tucson Water); the city says its plan will be updated for the new federal guidelines. Water bills are rising too: the rates approved in May 2026 raise Tucson Water's revenue by 3.5 percent a year from fiscal 2027 through 2030 (Tucson Water).
Groundwater, and why new homes still get built
Before CAP water arrived, Tucson ran almost entirely on groundwater and the water table fell year after year. Since then the Tucson Active Management Area has been at or around safe yield, meaning no more pumped out than goes back in, since 2010, and groundwater levels have risen by 60 to 200 feet in some areas (UA Water Resources Research Center). Inside an active management area, a new subdivision cannot be sold without showing a 100-year assured water supply, either its own certificate or a commitment of service from a provider the state has designated as having one (A.R.S. § 32-2181).
People here also use less than they did. Tucson Water's total use per person fell from 179.4 gallons a day in 2000 to 128.9 in 2024, and residential use from 111.5 to 71.7 gallons, while the population grew (Tucson Water FY2025 Conservation Report).
What to check about water when you buy
- Who supplies the home. Inside Tucson it is usually Tucson Water, but Marana, Oro Valley, Metro Water, Flowing Wells Irrigation District and the Community Water Company of Green Valley each serve their own areas, and Pima County points buyers to the state's map of community water systems to look one up (Pima County)
- Outside a city or town, read the seller's Affidavit of Disclosure. For unincorporated land sold by an owner of five or fewer parcels, it must say whether the water comes from a private water company, a city, a private well, a shared well or no well at all, and whether water is hauled, and it must reach you at least 7 days before the transfer (A.R.S. § 33-422)
- If the home has a well, the change of ownership has to be reported to the Arizona Department of Water Resources (A.R.S. § 45-593); ask for the well's registration, any shared-well agreement and a recent water test, and have it inspected during your inspection period
- A household well is limited to 35 gallons a minute, and inside an active management area a new one generally cannot be drilled within 100 feet of a designated provider's water lines (A.R.S. § 45-454)
- Rural parts of Pima County rely mainly on private wells (UA Water Resources Research Center), so the questions above matter most there
The bottom line
The Colorado River's numbers are serious, and the details of how Arizona and Tucson absorb the 2027 cut were still being worked out on November 2, 2026. But the cut falls first on agriculture, Tucson has spent decades storing river water underground and bringing its groundwater into balance, and the city itself describes its supply as resilient. For a home buyer, the practical questions are the ones above: who supplies the house, and if it is a well, what shape the well is in.
If you are weighing a move, our Tucson relocation guide and cost of living in Tucson cover the rest of the picture.
