For most datacenters the actual largest source of water use is indirectly from power generation (coal, nat gas). Solar reduces that a lot also.

Funny how nobody asks the folks who build golf courses "what about water usage?"

hint: An individual 18-hole course uses between 300,000 to 1 million gallons per day

The water isn’t actually used. It is slightly warmed.

Most data centers are closed loop systems, they circulate the water over and over again.

You understand, the water isn't used up? It's not even used up in agriculture. Even when you drink a glass of water, the water doesn't actually disappear, soon someone else will be drinking it. The same water that was on the earth when the dinosaurs walked the planet is still on the earth today. No need to panic about someone using water.

The only reason to be concerned is if someone is mixing the water with other chemicals at a rate faster than the natural filtration and then not paying for the treatment to purify the water again. But that is not an issue with data centers. Merely using water is a concern only for people who don't understand how matter is preserved, but a school physics book should dispel those concerns.