Voters this week passed 40 of 41 proposed ballot measures placing restrictions on some of the more than 2,000 new facilities planned around the nation, with water and power topping ratepayers’ concerns, but calculating how much each data center draws from local resources is elusive because operators typically report usage figures companywide instead of site by site. Giant 1-gigawatt AI data centers from the likes of Meta, Google, Amazon and SpaceX can consume up to 10 million gallons of water per day, according to Shaolei Ren, a data center researcher and professor at University of California, Riverside, with the exact number varying greatly depending on the hardware inside, where it’s built, and the cooling method used. Legacy data centers are often air-cooled, while modern AI data centers filled with high-power, denser GPUs rely on liquid cooling; water is about 3,000 times more efficient for cooling these GPUs, according to Equinix sustainability head Christopher Wellise, and the latest rack-scale AI systems, Nvidia’s Vera Rubin and Advanced Micro Devices’ Helios, rely on liquid cooling. Most large AI data centers use a closed-loop liquid cooling system that uses very little water daily, but Equinix, which doesn’t disclose water consumption at individual sites, consumed 1.2 billion gallons of water across its operations in 2025, up 10% from a year prior, and total water consumption depends far more on an additional cooling