Data centers in North America used nearly 1 trillion liters of water last year, about as much as New York City uses in a year.
Shareholders are now asking for site-specific information to spot risks and make sure companies are actually reducing their impact.
Amazon has started sharing more data and focusing on efficiency; Microsoft says it's tackling sustainability head-on.
Google hasn't responded yet, which is making some investors nervous about its promise to run on carbon-free energy by 2030.