When Jenn Duff heard that Meta, the parent company of Facebook, wanted to build yet another data center in Mesa, Ariz., she was immediately suspicious. “My first reaction was concern for our water,” Duff said. The desert city of half a million residents was already home to large data centers owned by Google, Apple and other tech giants, and Duff, a city council member, feared for the city’s future water supply. … Mesa is only one of many cities and towns in the West wrestling with the expansion of water-guzzling data centers. For years, data centers have come under scrutiny for their carbon emissions. But now, as a “megadrought” continues to ravage the Southwest and the Colorado River dwindles, some communities charge that the centers are also draining local water supplies.