I'm not sure why people are focused on water for the data centers when that's their smallest issue. The electricity usage is the concerning environmental factor
Water usage by comparison is dominated by agriculture, particularly animal agriculture. Even in water scarce areas, growing cattle feed is a leading source of drought
Correspondingly, our hydrologic modelling reveals that cattle-feed irrigation is the leading driver of flow depletion in one-third of all western US sub-watersheds; cattle-feed irrigation accounts for an average of 75% of all consumptive use in these 369 sub-watersheds. During drought years (that is, the driest 10% of years), more than one-quarter of all rivers in the western US are depleted by more than 75% during summer months (Fig. 2 and Supplementary Fig. 2) and cattle-feed irrigation is the largest water use in more than half of these heavily depleted rivers
https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1064&context=wffdocs