I'm not sure, because of two reasons.

First, I don't see the banks of dry coolers or chillers required to cool that amount of water in many of the data center photos.

Second, our closed loop data center is not losing that amount of water, so losing 10 billion gallons of water to evaporation across that many data centers seems unrealistic, even with evaporation for humidity balancing and dry-cooler boosting reasons.

Sitting on top of a data center and directly working on it has its perks, apparently.

“Open loop” cooling means there are evaporative cooling towers being used to cool the chilled water loop water: https://en.wikipedia.org/wiki/Cooling_tower

Adding evaporative cooling towers to a chilled water loop that uses chillers can double the efficiency.

A power plant that draws water from an intake, uses it to reject heat, cools it down, and then discharges it back to the stream/lake/ocean is once-thru cooling.