Drought and the availability of sufficient clean water are serious challenges. Using water efficiently is therefore important for households, businesses and data centers. The share of data centers in national drinking water use is small, but the local availability of water and its use during hot, dry periods do deserve attention.
Servers generate heat and therefore need to be cooled continuously. Data centers can use different techniques for this. Many data centers cool almost entirely with outside air or dry cooling systems and use hardly any water for cooling. Other data centers use water at warm moments to cool more efficiently.
A commonly used technique is adiabatic or evaporative cooling. In this process, water evaporates in the cooling system, which lowers the temperature of the cooling air. Especially on hot days, this can reduce the electricity used for cooling.
The choice of cooling system is therefore a trade-off between factors such as water use, electricity use, local conditions and operational reliability. Lower electricity use can also lead to lower CO₂ emissions, although this also depends on how the electricity is generated. Data centers are major purchasers of renewable electricity: 99.9% of the surveyed Dutch colocation data centers purchase green electricity through energy contracts and Power Purchase Agreements (PPAs) (SODD, 2025).
Statistics Netherlands (CBS) does not publish a separate total for all Dutch data centers. In CBS statistics, data centers fall under the broader information and communication sector. In 2021, this sector used approximately 1 million m³ of drinking water. This represented around 0.09% of total Dutch drinking water use that year. By comparison, households accounted for approximately 72% and industry for approximately 13%.
Source: CBS
This figure shows that the national share is limited. However, a national percentage does not tell the whole story: locally, water use can carry more weight, for example when several large users depend on the same drinking water supply.
The water source used differs per data center. Some data centers use drinking water for cooling, while others use industrial water, rainwater or treated wastewater, for example. The availability of such alternatives depends partly on the location, the required water quality, existing infrastructure and the scale of the data center.
The water use of data centers is not the same throughout the year. Data centers with evaporative cooling generally use water mainly when outdoor temperatures are high. As a result, their water use may increase precisely during hot, dry periods, when pressure on the water supply may also be greater.
That is why not only total annual use is relevant, but also where, when and from which source water is used. Possible measures include storing rainwater from wetter periods, using treated wastewater, and limiting or temporarily switching off evaporative cooling. Which solution is appropriate differs per location.
Water Usage Effectiveness (WUE) is increasingly used to provide insight into the water use of data centers. This metric indicates how many liters of water a data center uses per kilowatt hour of electricity consumed by the IT equipment. The lower the WUE, the more efficient the water use. Modern water-cooled data centers aim for a WUE below 1.0 liter per kWh.
WUE makes developments within a data center visible, but comparisons require context. The local climate, cooling technology and measurement method influence the outcome. WUE also does not distinguish between drinking water, rainwater and other sources. That is why the water source used and the location of the data center should also be stated.
For data centers with an installed IT capacity of at least 500 kW, European reporting obligations apply for energy and water performance, among other things. This makes the water use of larger data centers more transparent and easier to compare (European Commission).
Data centers can reduce their water use in various ways, for example by implementing:
Alternatives to drinking water are also being explored. Examples include rainwater harvesting, treated wastewater or industrial water. Around 20% of the surveyed Dutch colocation data centers are already investing in rainwater harvesting and 15% are considering doing so (SODD, 2025).
Such sources are not available at every location or automatically more sustainable. Here too, the origin, availability, required treatment and impact on the surrounding area must be considered.
Blijf op de hoogte van het laatste datacenter nieuws
