Water Stress and Drought Risk in Data Center Siting

Three different questions often get blurred together. Water rights ask who may legally take water (see water rights and groundwater). Water stress asks how much of a basin’s renewable supply is already spoken for, on average, over decades.¹ Drought asks whether this year, or this decade, is running short of normal.² A site can score well on one and badly on another: a basin with low average stress can still go through a severe drought, and a high-stress basin can look fine in a wet year.

For a data center, the exposure depends on the cooling design. Lawrence Berkeley National Laboratory estimated that U.S. data centers directly consumed about 17 billion gallons of water in 2023.⁹ Most of that is evaporation in cooling systems, so a campus using evaporative cooling is more exposed than one using closed-loop cooling. Our guide to data center water requirements covers the design trade-offs.

Even a waterless design is not fully insulated. LBNL’s estimate of indirect water use, the water consumed at power plants to make the electricity data centers draw, was about 12 times the direct figure in 2023.¹⁰ Water stress at the generating plants that serve a region can therefore affect power supply and prices, a point worth raising in climate and cooling and power reviews.

The World Resources Institute’s Aqueduct is the most widely used public screen for water stress. Version 4.0, published in 2023, provides 13 indicators of water risk, with baseline water stress as the headline measure.¹ Baseline water stress is the ratio of human water withdrawals to available renewable supply in a watershed, reflecting underlying hydrology rather than how well the area is managed.¹³

In high-stress areas, 40% or more of available supply is withdrawn every year; in extremely high-stress areas, 80% or more.³ At those levels, users compete for what is left, and a dry spell can quickly produce restrictions.

What Aqueduct does not tell you

• It works at the watershed scale. A city with senior rights, reservoir storage or imported water can be more secure than its basin score suggests, and a small system can be less secure.
• It is a baseline, built from long-term averages, not a forecast of next summer.¹
• It does not say whether a specific utility has capacity, rights or treatment headroom for a new large customer. That comes from the utility and a will-serve letter.

The U.S. Drought Monitor is the standard national map of current drought. It is produced jointly by the National Drought Mitigation Center, USDA and NOAA, released every Thursday, and reflects conditions over the previous week.² It uses five categories: D0 (abnormally dry, going into or coming out of drought) and four drought levels, D1 through D4, from least to most intense.²

Authors combine precipitation, temperature, soil moisture and streamflow data with local reports, so the map is a consensus judgment rather than a single formula.² That makes it good for answering two siting questions:

• How often has this county been in D2 or worse over the past 10 to 20 years, and for how long? The weekly archive answers that.²
• Is the area in drought now, and has the water provider triggered its drought contingency plan or restrictions?

A drought history does not by itself predict supply cuts. The link runs through the provider’s drought plan, which typically sets stages that restrict outdoor and commercial use. Ask whether large industrial and data center customers are curtailed in those stages, and whether the contract treats deliveries as firm or interruptible. Drought also overlaps with heat, which raises cooling demand at the same moment supply tightens; see climate change and future heat risk.

A data center is built to run for decades, so the question is not just whether water is available today. In January 2025, USGS released its National Water Availability Assessment, which found that nearly 30 million people live in areas where surface water supply is highly limited relative to use.⁵ E&E News reported the most severe limitations in California, the arid Southwest, much of the Great Plains and Texas.⁶ The largest demands nationally are irrigation, public supply and thermoelectric power.⁵

Shared rivers: the Colorado example

Where cities depend on a shared river, cuts are set by basin rules, not local weather. For 2026, Lake Mead is in a Level 1 Shortage Condition, which requires Arizona to reduce use by 512,000 acre-feet (about 18% of its share) and Nevada by 21,000 acre-feet, with Mexico taking 80,000 acre-feet.⁷ The guidelines behind those cuts expire at the end of 2026. On August 21, 2026, Interior finalized operating guidelines for 2027 and 2028, noting that combined storage in Lake Powell and Lake Mead had not been this low since before Powell began filling in 1963.¹¹ Shortage tiers for 2027 and later follow those new guidelines, so check Reclamation’s latest 24-Month Study for the current year’s cuts.

Plans that do not yet count data centers

State and regional water plans are a good guide to projected shortages, but they may lag data center growth. The Texas Water Development Board adopted an initial 2027 State Water Plan without the data center forecasts that petitioners had requested.⁸ The board cited limited data, noting that data centers largely buy water from public systems whose projections do not separate that use.¹² The Houston Advanced Research Center estimated that Texas data centers used about 25 billion gallons in 2025, counting both cooling water and water used to generate their electricity (roughly 0.4% of statewide use), and that this could reach 29 to 161 billion gallons by 2030 depending on growth and cooling choices.¹³

Water stress is now a reputational and approval risk, not only an engineering one. Reporting on a Bloomberg analysis of WRI and market data found that close to two-thirds of U.S. data centers built or in development since 2022 are in high water stress areas, with five states accounting for 72% of those sites.⁴

Tucson shows how this plays out. In August 2025 the city council voted unanimously to end its involvement in Project Blue, a proposed data center campus, after weeks of public pressure focused on water, power and transparency.¹⁴ The water rights guide covers the large-user rules the city adopted afterward.

In stressed areas, expect questions about gallons per day, the source, drought curtailment and whether the project uses potable water at all. Projects that rely on reclaimed water or closed-loop and waterless cooling have better answers. Our guide to community engagement covers how to prepare them.

1. 01Look up the site’s watershed in Aqueduct and note the baseline water stress band.¹
2. 02Pull the county’s U.S. Drought Monitor history and count weeks in D2 or worse.²
3. 03Identify the actual source: city system, groundwater, a shared river or reclaimed water, and how far upstream decisions (such as Colorado River shortage tiers) reach it.⁷
4. 04Read the regional or state water plan for projected shortages, and check whether it accounts for data centers.⁸
5. 05Ask the provider for its drought contingency plan and how large customers are treated in each stage.
6. 06Match the cooling design to the answer. In high-stress or drought-prone basins, design for low potable use from the start.

None of these sources replaces the provider’s written commitment and a hydrologist’s view of a specific aquifer or river. They are first-pass screens that tell you how hard to look. Our tools and methodology pages explain how BlackForge folds water into a site screen, and you can get a site reviewed if you want water weighed alongside power and land.