A quarter of data centers sit in areas short on water

About one in four data centers is in an area short on water, according to a new study. The buildings that power AI and online services need water to stay cool. Many are going up where towns and farms already compete for the same supply.

Why data centers use water

Data centers use water to carry heat away from their equipment. In evaporative cooling, some of that water turns to vapor and does not return to the local system. Making electricity and building hardware also use water indirectly, the Pacific Institute notes.

Timing matters too. Demand peaks in hot, dry periods, when supplies can be tight and other users need more. Meeting those peaks can require extra utility equipment and spending.

Who shares the supply

"They are landing on top of the water supply of cities and farms," said study lead author Lorenzo Rosa, in an American Chemical Society release. Cities and towns are the largest water users near nearly 41% of the facilities studied. Agriculture is the main user near another 28%.

The study also looked ahead. If the world warms by 3°C compared with around 1900, about a third of existing data centers would face water shortages. That result applies future climate to current sites. It does not account for new data centers that may be built.

Averages can hide the problem

The Potomac River basin shows why. An analysis by the Interstate Commission on the Potomac River Basin estimates average data center water use in the Washington area in 2025 at about 4 million gallons a day. On the busiest day, it was approximately 15 million gallons.

Cooling choices explain some of the gap. Around 40% of facilities in that analysis use only air cooling. Many others lean on cool winter weather. The commission cautions that methods using less water often need more energy.

Communities also face a information gap. The Pacific Institute says there is no standard reporting on data center size, location and water use, which makes projects harder to judge.

What to do

If a data center is proposed near you, the local planning board or water utility is the place to start. Questions worth asking:

• Where would the cooling water come from?
• How much could it use on the hottest days?
• What happens during a drought?
• Who pays for any water-system upgrades?
• Will the operator have to make its water use public?

Google publishes data center water reporting, and Microsoft offers local environmental fact sheets. They can show water use where facilities operate, but they do not reveal the footprint of an individual chat.