01 — The concern
The concern
When residents hear 'data center,' many picture cooling towers evaporating millions of gallons. Closed-loop designs are different, but the term is sometimes used loosely. Communities need to know which design is actually proposed and how much water it will really use.
02 — What the data says
What the data says
- Closed-loop liquid cooling recirculates a fixed volume of water or coolant through pipes and heat exchangers. Water is lost only to leaks, blowdown and minor evaporation, not as the primary heat-rejection path.
- The same approach is used in hospitals, universities, district energy plants and semiconductor manufacturing, settings where water reliability and quality matter.
- Air-cooled and hybrid systems use little or no water but consume more electricity. Closed-loop designs balance water and energy use.
- Direct-to-chip liquid cooling for high-density AI hardware can be closed-loop and typically uses less water than traditional cooling towers because heat is captured closer to the source.
- 'Closed-loop' is not a guarantee of zero water use. Makeup water, water treatment chemicals and blowdown disposal still need to be disclosed and permitted.
03 — What responsible development looks like
What responsible development looks like
- Require the developer to name the cooling technology and publish projected annual water withdrawal and consumption.
- Distinguish 'closed-loop' from 'zero water' by disclosing makeup water, blowdown and chemical use.
- Match the cooling design to local water availability and wastewater capacity.
- Use non-potable or reclaimed water for makeup where feasible.
- Report actual water use annually against the projection.
04 — Kentucky context
Kentucky context
Kentucky's water resources are generally abundant, but local treatment and distribution capacity govern what a specific site can use.
The Kentucky Division of Water permits withdrawals; KPDES permits govern discharge. Both records are public.
Several Kentucky data center proposals, including TenKey in Franklin, have stated they will use closed-loop cooling. The specific design and water source should still be confirmed in permit filings.
05 — Sources
Sources
Data center energy and water research
Source: Lawrence Berkeley National Laboratory
Water withdrawal and KPDES permit records
Source: Kentucky Division of Water
Local water district capacity studies
Source: Local water districts and municipal utilities
Project-specific cooling and permit disclosures
Source: Local data center developers
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