Question to the Department for Environment, Food and Rural Affairs:

To ask His Majesty's Government what estimate they have made of the water usage by data centres in the United Kingdom, and what sustainable sources of water will be used for this purpose.

Defra works closely with other Government Departments on plans to support the economic opportunities data centres bring, whilst making sure these developments are sustainable for local water supplies. Defra will continue to work with Ofwat to identify ways in which we can reduce overall water demand and achieve a secure supply of water for customers and the environment.

The water requirements of data centres vary, largely depending on the type of cooling systems used. Air cooled systems do not require very much water but are much more energy intensive. Closed loop systems reuse water, so have much lower water requirements than open loop systems.

As part of meeting the national statutory target to reduce the use of public water supply in England per head of population by 20% by 2038, Defra have set out an interim target to reduce non-household water use by 9% by 2030. We are currently working with TechUK, the trade association for data centres, to increase Defra and the Environment Agency's understanding of current water usage and cooling technologies being used.

When data centres are planned and designed, consideration should be given to the types of cooling technology being selected and the corresponding water needs. The water for cooling systems does not need to be drinking water quality. Consideration must also be given to where the data centre is going to be located to ensure that any water needs can be met.

The Environment Agency’s upcoming National Framework for Water Resources (2025) highlights the need for joined-up planning between different water-using sectors to identify collaborative solutions for water resources.