Pima County imposed a 120-day moratorium on new data-center projects in September 2026, The Verge reported on October 29. Ceres estimated that Phoenix-area data centers used about 385 million gallons over the summer before its March 2026 estimate and projected annual direct use of about 3.8 billion gallons, figures reported by Grist.
Those figures describe different periods and water pathways. The county action concerns new projects; the Phoenix estimates concern direct use across a metro area, while a separate forecast covers water used to generate electricity.
What the Arizona water estimates measure
Ceres’s estimates, reported by Grist, distinguish the Phoenix-area water used at data centers from the water used at power plants to meet data-center electricity demand.
| Measure | Geography and scope | Period | Amount |
| Direct-use estimate | Phoenix-area data centers | Summer before the March 2026 estimate | About 385 million gallons |
| Direct-use projection | Phoenix-area data centers | Annual projection | About 3.8 billion gallons |
| Power-generation projection | Arizona power plants serving data-center electricity demand | Annual projection | Up to 14.5 billion gallons |
Grist reported that the 3.8-billion-gallon projection would equal about 1% of regional residential water use and less than 0.5% of the region’s total water use in 2024. That’s a comparison of a projected annual data-center figure with regional water-use totals, not a metered count from a single facility. The power-plant projection measures a separate part of the footprint.
Estimates for a typical data center vary widely: figures cited by Grist range from 50,000 to 5 million gallons per day. Cooling design is one reason direct water use differs. The scale and boundaries matter when a facility-level estimate is compared with a metro-area projection.
Project Blue’s construction wells and Pima County’s moratorium
Beale Infrastructure’s planned Project Blue is a 600-megawatt data center on a 290-acre site near Tucson. Two approved wells allow up to 31 million gallons of groundwater per year. Beale said the wells would supply construction, not the operating facility.
The construction water story also includes city drinking water. Contractors used about 651,702 gallons from Tucson’s system for dust control before officials demanded water credits. County inspectors cited two dust-permit violations, each carrying a possible fine of up to $10,000.
The 120-day moratorium Pima County imposed in September applies to new data-center projects. It is a separate county action from the construction-well approvals for Project Blue.
Cooling design changes direct water use, while power plants add another pathway
Air-based cooling can reduce the water used directly at a data center, but the electricity it consumes has its own water footprint. Evaporative cooling can use more water and less electricity than air-based cooling, with the balance depending on the facility and power system.
Project Blue’s design changed to closed-loop air cooling. Members of a coalition opposing the project argued that the change could increase indirect water demand through electricity generation. Beale spokesperson Tony Burkart said the air-cooled design would not increase overall energy use. The statewide power-plant projection from Ceres is a separate estimate, not a calculation of Project Blue’s specific water use.
A separate example comes from NTT’s Mesa campus. In an English-language report published October 15, 2026, ABC15 Arizona said the closed-loop cooling system takes about 50,000 gallons to fill each building and circulates that water continuously. The report also described plans for seven data centers over two years and campus capacity above 200 megawatts upon completion. The initial fill is a facility-specific figure, not an estimate for Project Blue.
TSMC’s Arizona complex uses water for semiconductor manufacturing
The reported water figure for Taiwan Semiconductor Manufacturing Company’s Arizona complex is about 4.75 million gallons per day, mostly reclaimed wastewater with some groundwater. Semiconductor manufacturing requires highly purified water for processes such as rinsing wafers, so this complex-wide figure describes a different operation from a data center’s cooling demand.
The first Arizona fab recycles 60–65% of the water flowing through it. TSMC’s stated reuse target was 90% by 2028.
Arizona’s wider water use and where wastewater goes
Agriculture is the largest statewide water-use category in the cited reporting, accounting for more than 70% of Arizona’s water use. The University of Arizona Water Resources Research Center’s 2026 factsheet puts its broad industrial category at about 11% of state demand. That category includes data centers alongside other industries; mining and power generation each account for 37% of industrial use.
The route water takes after use depends on the facility. Evaporative cooling releases some water as vapor; recirculating systems can discharge concentrated blowdown, the water removed to clear accumulated materials. Treated wastewater may be reused for non-drinking purposes, but water intended for such reuse is not automatically suitable for drinking.
A 2023 audit of Apple’s Mesa data center traced its supply to the Colorado River watershed through the Central Arizona Project and the City of Mesa. The audit identified Lake Havasu as the canal system’s delivery source for this supply. Wastewater went to the Greenfield Water Reclamation Plant for treatment before agricultural use or groundwater recharge. That is one documented site’s water route, rather than a description of every Arizona data center.
