Running hot and running dry? Why cooling design is critical to the cloud

Driven by the surge in AI and cloud computing, new data centres are appearing at pace across Europe, North America and beyond. Much of the debate has focused on how we power sites. Yet there is another side to the story - one that determines whether those billions invested in servers actually delivers: cooling.

Servers run hot, 24/7, and without reliable water systems to manage that heat, even the best-connected facilities cannot operate as intended. In fact, cooling is fast becoming the next frontier in data centre design - and the decisions made today will echo for decades.

A growing thirst

Data centres are rapidly emerging as one of the most significant commercial water consumers worldwide. Current global estimates suggest that facilities already use over 560 billion litres of water annually, with that figure set to more than double to 1,200 billion litres by 2030 as AI workloads intensify.

The numbers at an individual site are equally stark. A single 100 MW hyperscale centre can use up to 2.5 billion litres per year - enough to supply a city of 80,000 people. Google has reported daily use of more than 2.1 million litres at some sites, while Microsoft’s 2023 global consumption rose 34% year-on-year to reach 6.4 million cubic metres. Meta reported 95% of its 2023 water use - some 3.1 billion litres - came from data centres. The majority of this is consumed in evaporative cooling systems, where 80% of drawn water is lost to evaporation and just 20% returns for treatment. While some operators are trialling reclaimed or non-potable sources, these currently make up less than 5% of total supply.

The headline numbers can sound bleak, but water use is not inherently unsustainable. Increasingly, facilities are moving towards closed-loop cooling systems that recycle water for six to eight months at a time, reducing continuous draw from mains supply. These systems require bulk storage capacity, both for the initial fill and for holding treated water ready for reuse.

Designing resilience into water systems

This is where design choices made early in a project pay dividends. Consultants working on new builds are specifying not only the volume of water storage or the type of system that should be used but also the standards to which they are built. Tanks that support fire suppression, potable water and process cooling need to meet stringent criteria - often set by insurers as well as regulators.

Selecting materials and coatings that deliver 30 - 50 years of service life can prevent expensive retrofits and reassure both clients and communities that these systems are designed to last. Smart water management, in other words, begins not onsite but on the drawing board.

For consultants who are designing the build specifications for data centres, water is more than a technical input - it is a reputational risk. Once a specification is signed off and issued to tender, it is rarely altered. Getting it right first time is essential. That means selecting partners who can provide not just tanks, but expertise: helping ensure that water systems meet performance, safety and sustainability criteria across decades of operation.

The payback is twofold. First, consultants safeguard their client’s investment by embedding resilience from the start. Second, they position themselves as trusted advisors in one of the most scrutinised aspects of data centre development. In a sector where projects often run to tens or hundreds of millions of pounds, this credibility matters.

Power may dominate the headlines, but cooling - and by extension water - is the silent foundation of the digital economy. Without it, AI models do not train, cloud services do not scale, and data stops flowing. The future of data centres will be judged not only on how much power they consume, but on how intelligently they use water - and that judgement begins with design.

If data centres are the beating heart of the modern economy, then water is the life force that keeps them alive. Cooling the cloud is not an afterthought. It is the future.