This data center is in Nebraska, not California, and motionlessveloc's comment that I replied to wasn't even limited to the US as there are local protests against data center water use in other countries.

Yes, water rights law is complicated. California's access to water from the Colorado River is due to the Colorado River Compact, which exists because state disagreed on the details of how water "goes back out into the environment".

That said, I was under the impression that many data centers use municipal water, which is more subject to market price, and not water allocated by property rights. While certainly some do, it isn't always so.