DES MOINES, Iowa – To the unknowing eye, the large, unassuming buildings on the northwest side of Altoona look like regular warehouses.

But the monolithic structures, known as data centers, take in hundreds of thousands of gallons of water a day to cool the servers they contain. That surprised some Iowans when we asked them to guess how much water is used.

The massive amount of water is causing some to look more closely at the top water users in a state experiencing another year of drought.

Daniel Scott, utility director for Altoona, says it’s “definitely a concern.” He told us the Meta data centers in Altoona can use up to a million gallons of water a day, one fifth of what the city can produce on its own. That’s moving him to consider new sources of water.

“We’re looking at bringing on a new water plant, a deep Jordan well, hopefully by 2026. And then that will give us an additional two million gallons of water a day that will address our future needs,” Scott said.

Over in West Des Moines, several data centers also use hundreds of thousands of gallons of water a day, but they have more water at their disposal. Christina Murphy with West Des Moines Water Works says the bigger concern in the summer is outdoor lawn watering; data center water use is just a fraction of West Des Moines’ total usage.

That fraction amounts to about two percent of the total water used in West Des Moines, compared with Altoona’s eight percent of data center water usage. However, an agreement between Meta and the city of Altoona allows Facebook’s parent company to use up to 16%.

While the raw amount of water usage demands attention during a drought, where the water is coming from matters too.

Tim Hall with the Iowa Department of Natural Resources notes that Altoona’s water comes from the Jordan Aquifer, a deep groundwater source. That aquifer is much less prone to drought.

The Iowa DNR coordinates water usage with other agencies and also looks to the future to make sure cities don’t get into a situation where they could run out of water.

“If someone comes in and says ‘hey, I want a permit to withdraw water for another data center,’ we look at what’s in the area, what’s currently being used, what the impact of a new source might be on existing sources both short term and long term and help make good decisions,” Hall said.

So while data centers aren’t using a concerning amount of water right now, and cities like Altoona are looking to expand the amount of water available, Hall says it’s still important to not waste water and to plan for the future.

“We tend to think of ourselves as a water-rich state but those conditions can fluctuate, and we tend to take for granted the fact that we’ve got water in our system. And while that’s always been the case, we just want to make sure that communities and users of water understand it’s a resource we have to take care of,” Hall said.