> When you're using water in a open-loop data center, you get in cool/cold water, add biocides and other chemicals to protect your infrastructure, then heat it and pump it back to the body of water (i.e. river, lake or an underground hole, or somewhere).

These are not power plants, there are zero data centers using open loop cooling that discharge loop water back into a waterway. It’s unnecessary when you’re cooling a data center.

The system is filled with water and begins operating. As water is lost to evaporation in the cooling towers, more water is added to the cooling loop.

At no point is any of the cooling loop water discharged back into a waterway, it gets recirculated through the system.

All that being said, closed loop cooling is much better in areas with a lack of water.