Finding out how much water data centers use is super-super-difficult because, as with everything else, data centers are super-super-secretive. It’s like they’ve got this super-super-big dirty set of secrets they don’t want anyone to know about. How much water do US data centers use? “We don't really know,” Lawrence Berkeley National Laboratory research scientist Dr Arman Shehabi explained to Data Center Dynamics. “I never thought it could be worse transparency than on the energy side, but we actually know less.”

If you want to control the message, control the data. If you want to control the metrics, control the data. Google, for example, considers its water use a ‘proprietary trade secret’ and won’t even allow public officials give out any details. What has Google got to hide? Is it secretly ashamed of its behavior? Even in 2009, some were aware of how wasteful data centers were when it came to water usage. A designer working on an Amazon data center admitted that “water consumption is super embarrassing. It just doesn’t feel responsible.”

“We have been really bad at reporting data centres accurately, largely because the data centres refuse to be transparent,” Philip Boucher-Hayes, a journalist for Irish national broadcaster, RTE, reported in 2022. “I spent months trying to get interviews with some of the hyperscale operators here. They refused.” Gauthier Roussilhe, a specialist in the environmental footprint of the digital sector, told me that he has been “trying to track down the water demand of data centers in the drought-stricken region of the US, and, first, it is very, very, very hard to get to the data where they are asking for water. Most data center operators like Google or Facebook, they don’t use their official names to make water demands. They use screen companies. It’s very hard to get data that can be used in research. So, most of the time you have to work with whispers, things that you hear when you go to professional events.” In the future, it’s going to become even harder to find water data, Gauthier told me. “In some US states, Google is building its own pumping stations so it will be even harder to know what is being extracted.”

The US National Security Agency data center in Bluffdale, Utah guzzles seven million gallons (32 million liters) of water every day. Local residents are suffering from water shortages and power outages. In 2021, the Mesa city council in Arizona “approved the $800 million development of an enormous data center,” according to NBC News. “But keeping the rows of powerful computers inside the data center from overheating will require up to 1.25 million gallons of water each day, a price that Vice Mayor Jenn Duff believes is too high. “This has been the driest 12 months in 126 years,” she said, citing data from the National Oceanic and Atmospheric Administration. “We are on red alert, and I think data centers are an irresponsible use of our water.”

According to a US Government report, a data center will need on average around 1.8 liters of water for every kWh consumed, predominantly for air conditioning purposes. The Berkeley Lab reported that US data centers were projected to consume approximately 73 billion kWh in 2020. That’s 131 billion liters of water for cooling. That would fill up 52,560 Olympic-size swimming pools. US data centers were projected to use a total of 660 billion liters of water in 2020, according to David Mytton, an expert in sustainable computing. 80% of this figure is for the water required to generate the electricity used in data centers.