Ammonia
Data centers are cooled using ammonia gas. The gas is cooled using water instead of air. Direct cooling of air with water is called a swamp cooler, and you do not want to that.
Once water is used in any process it is considered non-potable and can not be dumped back into the water table. That's why there are cooling towers (actually evaporators) to get rid of the water.
Biting the hand that feeds IT
