depending on states, some do use inordinate amount fo water because they just draw cold water from river and pass it through evaporators and that water evaporates from heat taken out of data centre.
The water taking heat out of an aisle inside data centre to the outside cooling plant may be a closed loop, but it all depends on how they manage to get rid of all that heat by dumping it into environment. Some may draw water from river and dump hot water back into river.