Municipal Water Review

Water use should be reviewed by cooling design, not by assumptions.

The same size data center can have very different water impacts depending on how heat is ultimately rejected outside: dry/air-cooled, evaporative, or hybrid. Internal liquid loops alone do not determine site water consumption.

Key review questions

What cooling system is proposed?

Require the applicant to describe both the internal cooling loop and the final heat-rejection method: dry/air-cooled, evaporative, or hybrid.

What is the water source?

Municipal water, well water, reclaimed water, surface water, and industrial reuse all have different impacts.

What are the peak and annual numbers?

Peak-day use and annual consumption both matter. One number alone can be misleading.

Educational illustration showing how server heat moves through cooling equipment and is rejected outside
Review the full cooling path

Ask what happens at the last step.

A liquid loop inside the building may be sealed and recirculating while the outdoor heat-rejection equipment still consumes water. Municipal disclosure should cover the complete cooling path.

See the cooling comparison

Policy approach

Reasonable requirements

Municipalities can require water-use estimates, cooling system descriptions, drought response plans, reporting requirements, and disclosure of whether reclaimed water can be used.

Common mistake

A blanket rule against "data center water use" may miss the point. Two facilities with closed internal loops can still have very different water impacts if one uses dry heat rejection and the other uses evaporative cooling towers.

Suggested ordinance language themes

Cooling disclosure: require a written description of the cooling system.
Water source: identify all expected sources of process and cooling water.
Annual estimate: require projected annual water consumption.
Peak-day estimate: require estimated maximum daily water demand.
Drought plan: require operating procedures during water restrictions.
Reclaimed water: require analysis of reclaimed or non-potable water feasibility where available.
Municipal takeaway: The correct question is not "does it use water?" The correct question is "how much, from where, under what conditions, and with what safeguards?"