One good way to save water is to use treated wastewater for cooling. xAI is building this kind of system in Memphis.[0] It'll connect to a nearby wastewater treatment plant and they'll need to build an additional treatment plant before the water can be used for cooling. It's a closed-loop system inside the data center, where they use clean water, and it connects to open-loop evaporative cooling towers with heat exchangers.

[0] https://www.datacenterdynamics.com/en/news/elon-musk-xai-mem...