Evaporative cooling has long been one of the most energy-efficient ways to cool a data center — and one of the most water-intensive. As AI-driven facility growth accelerates in regions that are not uniformly water-abundant, water strategy is becoming as central to facility design and community relations as energy strategy has been for the past decade.
The Trade-Off at the Centre of Cooling Strategy
Evaporative cooling technologies achieve excellent PUE performance by using water evaporation to reject heat, but this comes at a direct water consumption cost — every litre evaporated is a litre that must be replenished, typically drawn from local municipal or groundwater supplies. Closed-loop liquid cooling systems, by contrast, consume dramatically less water in ongoing operation, but historically have carried a less favourable PUE profile in some climates compared with the most efficient evaporative approaches, though this gap is narrowing considerably as warm-water liquid cooling and improved heat rejection technology mature.
Neither approach is universally correct. The right answer depends heavily on local water availability, local energy carbon intensity, and the specific climate conditions at a given site — a calculation that should be made explicitly and site-specifically, rather than defaulting to whichever cooling approach a developer has used most often regardless of location.
Why Water Has Become a Community and Regulatory Flashpoint
- Communities in water-stressed regions have become increasingly vocal about large facilities competing for water resources with residential and agricultural use
- The EU's data center reporting framework requires WUE disclosure alongside energy metrics, formalising water consumption as a tracked regulatory indicator rather than an unmonitored externality
- Several jurisdictions are beginning to factor water availability explicitly into permitting and planning decisions for large new electricity and water consumers, including data centers
A facility that solves its energy efficiency problem by creating a water scarcity problem has not actually solved its sustainability problem — it has simply changed which community bears the cost.
Designing Water Strategy by Climate Zone
A water strategy that makes sense in a water-abundant, cooler climate may be entirely inappropriate in a warmer, water-stressed region — and a genuinely rigorous approach to facility design treats this as a site-specific engineering decision rather than a fixed corporate standard applied uniformly across a global portfolio. This often means accepting a marginally less favourable PUE in water-stressed locations in exchange for a closed-loop cooling approach that meaningfully reduces water consumption, recognising that community and regulatory tolerance for high water consumption varies considerably by region and is likely to tighten further in many water-stressed markets.
Alternative Water Sources Are Gaining Attention
Beyond simply reducing consumption, some operators are exploring alternative, non-potable water sources for cooling — reclaimed wastewater, greywater, or in coastal locations, seawater with appropriate treatment — to reduce competition with municipal drinking water supplies even where overall cooling water volumes remain significant. These approaches typically require additional treatment infrastructure and careful engineering to avoid equipment fouling or corrosion, but they can meaningfully change the community and regulatory calculus around a facility's water footprint by decoupling cooling water demand from the same supply that serves residential and agricultural users.
Building Water Strategy Into Site Selection
DATAPERT incorporates water availability and strategy explicitly into our sustainability and feasibility work, ensuring cooling technology decisions reflect genuine local conditions rather than a one-size-fits-all approach. Start a project to discuss a climate-appropriate water strategy for your next facility.
