EUDCA
Water stewardship will define how data centers are built
Water is rapidly becoming a defining constraint for digital infrastructure. In a growing number of regions, water availability is emerging as a critical factor that will increasingly determine where and how data centers can be developed.
Michael Winterson, Secretary General of the European Data Centre Association (EUDCA) sees water evolving from an operational consideration into a core design principle: “Water stewardship will define how data centers are built.”
Across Central and Southern Europe, water stress is already influencing policy, planning and investment decisions. And as data volumes surge and AI workloads drive up cooling demands, the pressure on resources will only intensify. The implications are far-reaching. Design choices, cooling technologies and location strategies will increasingly be shaped by water constraints.
Winterson points out that companies like LCL, which have invested early in closed-loop cooling systems, show how forward-looking decisions today anticipate the standards of tomorrow. “The key question for the sector now is how to scale solutions across both new and existing infrastructure,” he says.
Why is water usage in data centers under increasing scrutiny?
Michael Winterson: “This has been building for several years. When the European Commission launched its ‘Fit for the Digital Age’ agenda, it already linked digital growth to broader climate neutrality. Not just carbon, but resources like water as well. When we set up the CNDCP in support of the European Green Deal, water stewardship was one of the first targets we defined. We introduced a benchmark of 0.4 litres of potable water per kilowatt hour. That was ambitious at the time. And for many existing data centers, it still is. If you rely on traditional evaporative cooling, it becomes extremely difficult to meet that level. So effectively, we were saying: future data centers should move away from those systems. The logical alternatives are closed-loop cooling, water recycling or the use of non-potable water. In reality, the sector is gradually moving towards designs where water use is close to zero – or at least minimal.”
What are effective ways to reduce water impact?
Michael Winterson: “There are three main levers. First: closed-loop systems, where potable water is no longer used for cooling. Second: recycling water within the data center itself. And third: using industrial or non-potable water, including water reused across industrial ecosystems, instead of drinking water. One of the key principles is simple: if you use water, use rainwater, grey water, or water from other industrial processes. That’s where a lot of untapped potential still exists in Europe.”
That requires infrastructure beyond the data center itself. What is missing today?
Michael Winterson: “What’s missing is a broader ecosystem approach. In many parts of the world, industrial water systems are standard. In Europe, they are still the exception. We believe there should be a much stronger focus on creating local or regional systems where water can be reused between different users, for example within industrial zones.”
Will stricter standards drive change?
Michael Winterson: “Standards will tighten. In fact, that is already happening. For new data centers, that will be a strong driver. If you know upfront what is expected, you design accordingly. But the bigger challenge is the existing estate. Retrofitting older data centers is complex and expensive. That’s where incentives can play a role.”
Europe is planning significant growth in data center capacity. How does that influence the debate?
Michael Winterson: “It changes the equation quite significantly. If Europe triples its data center capacity as planned, most of that will be new infrastructure. So, the real opportunity is to ensure that all new builds meet high standards from the start. At the same time, we shouldn’t ignore the existing data centers. But given the scale of growth, the priority should be getting the future right.”
Are there trade-offs when reducing water use?
Michael Winterson: “Yes, and they are important. Closed-loop systems, for example, can require more electricity. If that electricity is produced using water-intensive methods, the overall benefit may be limited. That’s why we always need to look at the full system. Water, energy and carbon are interconnected. You can’t optimise one without considering the others.”
What technological developments will shape the next phase?
Michael Winterson: “One key trend is the rise of liquid cooling, especially driven by AI workloads. It is far more efficient for high-density computing and typically operates in closed systems, which reduces water use. The real challenge is cost. These technologies are still relatively expensive, so scaling them will be critical to broader adoption.”
What role should policymakers play?
Michael Winterson: “The challenge is that we are still thinking too much in silos. Data centers are being asked to optimise their own footprint, which is fair. But we also need to look at how they interact with other sectors. If we move towards a more circular, system-level approach where water, energy and heat are all part of a broader ecosystem, we can unlock much more efficient and sustainable solutions.”
Laurens van Reijen, CEO LCL
“Many data centers use large amounts of cooling water because it is cheaper than energy-based cooling. In doing so, they reduce their energy bills but invisibly put pressure on our water resources.”
Laurens van Reijen, CEO LCL
“The debate on the correct pricing of water must urgently begin – not only for agriculture or industry, but also for the future of our economy.”
