They're probably using cooling towers, which cool through evaporation. They should be using reclaimed though.

I worked 10 years at a data center, all that water is recycled - it is very carefully chemically balanced so as to not corrode the pipes and pumps, no they do not use it once and dump it out.

From what I've seen it's "not worth the effort or expense" to reuse the water. Some of them literally just send tap water through the cooling loops and then into the sewer drains

Because the massive stacks of high-powered chips that they use, tend to get very hot. They don't use the kind of computers that work through passive cooling.

I say, as my Laptop burns into my lap.