Data centers in the U.S. gulp an estimated 388 billion liters of potable water every year. Experts say that's enough water to fill 155 million Olympic pools or 820 billion grande drinks at Starbucks. Like a laptop computer, rows of data center servers and other information technology (IT) equipment need to stay cool to work well. Unlike fan-cooled laptops, data centers—dense with servers stacked into rows and rows of racks—are mostly cooled using chilled-water systems. Those systems rely on large volumes of water that typically get discharged into the environment. To date, data-center water consumption has not been a target for environmental activists. "We expect that to change quickly," says Jakob Carnemark, senior vice president for mission critical facilities in the New York City office of Skanska USA, which based the 388-billion-liter figure on data from the nonprofit building infrastructure group, ASHRAE.