Data Centers Sit Atop Water That Cities and Farms Use

A new global map finds 2,315 of 9,347 data centers already sit where water demand exceeds supply for at least one month a year. The study, in ACS Environmental Science & Technology, puts that share at 25%. Under a climate 5.4 degrees Fahrenheit (3 degrees Celsius) warmer than in 1900, 3,045 of those same sites, 33%, would sit in a water gap.

The servers are not the party most exposed. Cities are the main water users beside 41% of the sites, and irrigated farms beside another 28%. Lorenzo Rosa, a principal investigator at the Carnegie Institution for Science and the lead author, said the buildings are landing on top of the water supply of cities and farms, not empty land.

25% of Sites Already Face a Water Gap

Rosa and colleagues mapped 9,347 operating data centers against local supply and against demand from cities, farms, factories, and power plants. They used water conditions from 2001 to 2010 as the baseline. A water gap is a month when demand in that grid cell exceeds available supply, so use is unsustainable and stress rises.

Electricity for these halls can travel on a grid. Cooling water comes from nearby rivers, lakes, and aquifers whose levels swing by season. Rosa said energy use is metered and reported in detail, while water scarcity is measured locally, inconsistently, and often not at all, which is why the team built the map.

HOW LONG THE WATER RUNS SHORT

Those 523 sites, about 6% of the global stock, sit in a gap for 9 to 12 months a year. The dry stretch is longest in the western United States, Mexico, the Mediterranean, the Middle East, India, and northern China. Northern Europe and much of the eastern United States show little gap.

The paper is in volume 60, issue 39, pages 27780 to 27791, and it is part of the journal’s 60th anniversary issue. Matteo Sangiorgio of Politecnico di Milano ran the analysis with Rosa. Co-authors are Bridget R. Scanlon of the University of Texas at Austin Bureau of Economic Geology, Marco Mazzotti of ETH Zurich, and Joseph Berry and Anna M. Michalak at Carnegie.

The Neighbors on the Same Pipes

Each site was assigned to the water user that already dominates its 0.5-degree grid cell. Cities and municipal systems are first. Farms are second. Factories, power plants, livestock, and mines fill out the rest. Cities and farms together are the main users beside 69% of sites, 6,425 halls on the same water as houses, shops, and crops.

WHO ALREADY DRAWS BESIDE EACH SITE

That farm column is the large draw in any dry basin. In 2020, crop irrigation in the lower 48 states withdrew 110,904 million gallons a day, and about 72% of that water never returned to local streams or wells. Groundwater supplied 63.5% of those withdrawals. August was the peak month, which is also when server halls dump the most heat.

These facilities are not landing in empty landscapes. They are landing on top of the water supply of cities and farms.

Lorenzo Rosa, principal investigator, Carnegie Institution for Science

The discussion in the paper is blunt about who wins a short month. Water scarcity is often framed as a brake on data-center growth. In practice, the authors write, the halls typically have the money and the standing to secure water whenever it is available. Conditions rarely force a permanent shutdown. The primary risk, they conclude, may not be to the operators but to other users in the same basins.

Why Water Could Not Be Mapped Like Power

Site pickers still hunt megawatts, tax breaks, and fiber. Water shows up later, as a local permit and a cooling design. Evaporative towers take water from the same systems that serve taps and fields, then lose much of it to steam. Air cooling and closed loops cut on-site use, but they shift heat onto power plants that also drink from rivers.

Rosa has described the industry’s first question as where the megawatts come from, and the second, still new, as where the liters come from and who gives them up. The map is an attempt to put that second question on paper. Saoradh Enterprise Partners LLC in Boulder, Colorado, supplied the facility list from its Hydrogen Market Model. Exact latitudes stay private, so the public files are country totals, not pins.

We analyzed water scarcity risk across 9,347 data centers worldwide.

1 in 4 are already in areas where water demand exceeds supply for at least one month/year.

Under future climate conditions, that rises to 1 in 3.

Read the paper: https://t.co/YDD6WUUBXD pic.twitter.com/kUJdJ75294

— Lorenzo Rosa (@TheRosaLab) September 24, 2026

National tallies hide the fight. Irrigation, thermoelectric plants, and public supply already account for about 90 percent of daily freshwater use in the lower 48, some 224,000 million gallons a day. A new cooling load can be a rounding error in that ledger and still be a crisis on one utility’s pipes. Conservation rules then land on households and farms first, because the operator can pay and stay in the queue.

Most of the Extra Stress Lands in the United States

The United States hosts 3,619 of the 9,347 sites, 39% of the global fleet, far ahead of the United Kingdom (420), Germany (410), China (344), and Canada (268). Of the U.S. total, 2,855 halls, 79%, sit outside a water gap on the baseline map. The other 764, 21%, do not: 260 face 1 to 4 months, 402 face 5 to 8, and 102 face 9 to 12.

Eastern clusters, including the dense Virginia market, sit in relatively wet basins. Parts of the West and South see 4 to 8 months of gap, and some spots stay short most of the year. That is also where municipal and farm demand already overlap the sites, the authors note.

Warm the hydrology by 3 C and 505 more U.S. halls join the gap list, for 1,269 sites, 35% of the national stock. Globally the added count is 730. Most of those extra buildings are in the United States, which already holds 39% of the world’s data centers. The study does not add future campuses. It takes today’s 9,347 addresses and asks what the water looks like if the climate is 5.4 F warmer than in 1900, a level the authors said could arrive in 10 to 40 years.

India and the Gulf Face Longer Dry Seasons

Share of sites in a gap is highest outside the U.S. fleet’s wet eastern core. In India, 73% of facilities, 173 halls, see at least one short month: 66 for 1 to 4 months, 29 for 5 to 8, and 78 for 9 to 12. In the United Arab Emirates, 93% of data centers, 50 halls, sit in a gap. Spain is the most exposed in its region, with 64%, 95 halls, of which 61 see 1 to 4 months and 34 see 5 to 8.

China’s 344 sites look different under heat. About 31 more would face some gap, taking the total to 177, or 51%. In India the headline share stays similar, but the 5 to 8 month band swells from 29 halls to 101, a shift the authors flag as sensitive to how climate models treat the monsoon. Australia moves from 75 affected sites to 90.

WHERE THE MAP RUNS DRY

• Western United States: Seasonal gaps of 4 to 8 months in places, with some sites short most of the year, on top of city and farm demand.
• India: 173 halls, 73%, already miss water for at least one month, and 78 of them for 9 to 12 months.
• Gulf states: Prolonged stress, including 50 UAE sites, 93% of that country’s mapped halls.
• Spain and the Mediterranean: 95 Spanish sites, 64%, already in a gap, with Mexico and northern China also on the hotspot list.
• Northern Europe and the eastern United States: Dense clusters with little water gap on the baseline map.

South Asia and the Middle East stand out as the most water-stressed regions in the figures. The eastern U.S. and Northern Europe are the counterpoint: lots of halls, little monthly gap. Siting for cheap power and cheap land has not tracked that split.

An Open Question on Who Goes Short

The authors do not claim that a water gap equals a dry tap at the server hall, or a lost harvest next door. They say whether exposure becomes a real shortage for data centers or for other users remains an open question, and that it will take local studies to settle. They still argue that operators should fold local water plans and pipes into long-term siting, because the cooling load is stacking onto basins that already fail some months.

Towns have not waited for that next paper. Zoning fights over water, power, and tax breaks have already reversed some data-center deals, including a full ban after a packed meeting in Andover Township, New Jersey. The pattern matches the study’s warning: the constraint is local, and the neighbor on the pipe is the one who feels it first.

WHAT WE KNOW

• Today’s stock: 2,315 of 9,347 mapped halls, 25%, already sit in at least one month of water gap on 2001 to 2010 hydrology.
• Who is beside them: Cities dominate at 3,852 sites and irrigated farms at 2,573, together 69% of the fleet.
• Who can pay: The paper finds the halls rarely go dark, because operators can secure water when it exists.

WHAT IS UNCONFIRMED

• Real shortages: The authors say it is still unknown whether the gap becomes a measurable loss for farms, households, or the servers themselves.
• New campuses: The 33% figure applies to today’s 9,347 sites under warmer hydrology, not to halls that have not been built.
• Local contracts: The global grid cannot see which utility would cut whom first in a dry month.

Five climate models and the H08 water model produced the future layer, as a multi-model average at +1.5 C and +3 C. The 3 C case is the one in the press note, 3,045 sites, 33%. Country files that back the figures are posted for later release; the pin map of each hall is not. Until utilities publish cooling volumes the way they publish kilowatts, cities and farms will keep learning about the new neighbor the hard way, after the concrete is poured.

Frequently Asked Questions

What Does a Water Gap Mean in This Study?

A water gap is a month in a 0.5-degree grid cell when total demand from all users exceeds available supply, so consumption is unsustainable and stress rises. The baseline uses hydrology from 2001 to 2010, not a single drought year, and it counts months rather than a yearly average that can hide a dry summer.

Who Provided the List of 9,347 Data Centers?

Saoradh Enterprise Partners LLC, a Boulder, Colorado, firm, supplied the facility file from its Hydrogen Market Model, and the authors thank the company for access. Because the coordinates are proprietary, the public deposit covers country totals and figure extracts, not the latitude and longitude of each hall.

What Warming Levels Did the Researchers Test?

They ran two future layers, +1.5 C and +3 C above the 1900 baseline, each as an average of five climate models (IPSL-CM6A-LR, UKESM1-0-LL, GFDL ESM4, MPI-ESM1.2-HR, and MRI-ESM2.0) feeding the H08 global hydrological model. The 33% headline is the +3 C case, which they described as 5.4 F warmer than 1900 and possibly 10 to 40 years away.

Why Are Exact Data Center Coordinates Not Public?

The authors state that spatially distributed lat/lon data came from the Saoradh compilation and therefore cannot be released, which is why maps that show individual sites in the paper have no matching public spreadsheet. Country-level counts, including the month-band splits and the dominant nearby water user, are the files scheduled to leave embargo after December 31, 2026.