Closed-loop cooling can sharply reduce routine water withdrawals because the same coolant is recirculated. However, it does not automatically make a data center water-free. Water may still be needed for initial filling, maintenance, humidification, backup cooling, or heat rejection elsewhere in the system.
Indirect water use also remains relevant when electricity generation consumes water. Claims of “zero water” should therefore state whether they refer only to on-site cooling, annual net consumption, or the facility’s wider energy-related footprint.