I can’t touch on all of them, but a lot of them do actually just make it disappear.

A lot of the large data centers use evaporative cooling. The water basically boils off as vapor they just pump into the sky. This is cheaper in many places than the electricity needed for condenser cooling or other methods as it requires less electricity. (Which at the scale of these data centers they literally are unable to get enough electricity). That water vapor can drift off as clouds and come down somewhere, but no guarantee where or when.

Some data centers also introduce more runoff of pollutants from their methane generators and such that can make the water unusable. If they do capture the vapor and reintroduce into the water table it isn’t always cooled down and the heat can cause major problems in the environment by raising temperatures. This can sometimes lead to the only thing surviving around the data centers being toxic algae or something.

There are so many more ways they can be problematic. That’s just scratching the surface