QUESTIONS
How much water does a data center use?
Anywhere from less than a house to more than a large office building, depending entirely on how it is cooled — and the cooling method is written in the application.
THE SHORT ANSWER
It depends almost entirely on how the building is cooled, and the range is enormous. Virginia's legislature studied its own data centers and found that most use about the same amount of water as an average large office building, or less, while a few require substantially more. Across the whole country the totals are large and rising fast: Berkeley Lab put direct water use by U.S. data centers at about 66 billion litres in 2023, roughly triple the 2014 figure.
Why one building can use a thousand times another
A data center's water use is a design decision, not a fact about data centers. Machines make heat, and the heat has to go somewhere. Evaporative cooling gets rid of it by evaporating water, which is cheap on electricity and expensive on water. Closed-loop and air-cooled designs use far less water and more electricity. Some sites use recycled or non-drinking water; some draw the same treated water that comes out of a tap.
This is why a national average tells you almost nothing about the building proposed down the road, and why the useful question at a hearing is not "do data centers use a lot of water" but "which cooling system is this one using, and where is the water coming from".
The water you do not see on the invoice
Generating the electricity a data center uses also consumes water, at the power plant rather than at the site. That water never appears on the facility's own bill, and a project's application generally will not mention it.
What to look for where you live
A serious application usually states the expected water use, often as gallons per day, and names the cooling system. Three questions are worth asking about it: is that drinking water or reclaimed water, what does the figure look like on the hottest week of the year rather than on average, and who is paying for any new pipe or treatment capacity.
If a project near you is on our map, its page lists the documents we have found for it.
WHERE THIS COMES FROM
- Data Centers in Virginia (Report 598)Joint Legislative Audit and Review Commission, Virginia General Assembly · December 9, 2024Virginia's legislature investigating its own largest data center market, at the legislature's request.
- 2024 United States Data Center Energy Usage ReportLawrence Berkeley National Laboratory, for the U.S. Department of Energy · December 2024
Find out what is planned near you.
General answers only go so far. The useful version of this question is about one parcel, one county and one meeting date.
OTHER QUESTIONS
- Do data centers raise your electric bill?The honest answer is that it depends on where you live and what has to be built — and the best recent evidence points in two different directions.
- Do data centers lower nearby property values?There is very little research, it does not show a large drop, and the one detailed U.S. study found the opposite — but it covered a single region.
- How close to homes can a data center be built?There is no national rule. Your county or town decides, the distances vary from none to several hundred feet, and the rules are being rewritten right now.
- What happens at a rezoning hearing for a data center?A planning commission recommends, elected officials vote, and the public gets a few minutes each — usually after the decision has been shaped in documents most people never read.