Questions Before ConcreteData centres in England and Wales
Cymraeg · Read in your language

Home › The issues › Water

The issues · Water

Water: who gets cut off first?

A large data centre can need a lot of water, to keep its computers cool and, indirectly, through the power stations that supply its electricity. How much depends on choices made early, and most of the figures we have are voluntary.

Why it matters

Everyone in an area draws on the same reservoirs, pipes and treatment works. A big new user that needs a reliable supply on the hottest days is a matter for everyone on that supply, not just its neighbours.

If the question of who gets priority in a drought is not settled before permission is given, it will be settled during the drought.

Key points

  • The main survey of data-centre water use in England was voluntary and anonymous, and covered 73 sites.[1][2]
  • Demand peaks on hot days. Water UK puts data centres' peak demand at about 14 million litres a day, roughly twice their everyday average.[3]
  • In North Wales, the proposed Menai Data Centre near Caernarfon is reported to need up to about 12 million litres of water a day at most, against about 700,000 litres on a normal day: seventeen times as much. It is the maximum that has to be supplied, usually in the hottest weather.[4]
  • 84% of proposed water-intensive data centres in the UK are in areas already short of water, or expected to be by 2040.[5]
  • The National Infrastructure Commission for Wales expects data centres to add to water demand, with pressure most acute in southern Wales, where most proposed Welsh capacity is.[6]
  • The UK grows only about 53% of its fresh vegetables and 16% of its fruit. Waste heat from data centres could warm glasshouses, and treated water could irrigate crops, if this is planned in from the start.[7][8]
  • Wales has a law requiring public bodies to protect the ability of future generations to meet their needs.[9]
  • In the EU, data centres must report their energy and water use, but the figures for each site are kept confidential. An investigation found the wording was copied from proposals by Microsoft and an industry lobby group.[10]
  • From 2027 the EU will publish a grade for each site, but not the figures behind it. The UK has no reporting requirement at all.[11]

Questions you can ask

Drafted in full so you can copy, adapt and send them. See the questions tracker for all of them, with a downloadable version.

Ask: the local planning authority (planning officer for the application)

“Please confirm the applicant's estimated annual and peak-day water consumption for this proposal, the assumptions behind the peak figure, and whether the water company has confirmed in writing that it can meet that peak demand during drought conditions. If this information is not on the planning file, please say so.”

Follow-up: If not provided, request the water company's consultation response and any correspondence under the Environmental Information Regulations via WhatDoTheyKnow, addressed to the council and, separately, to the water company.

Ask: the Welsh Government minister responsible for water (in England, the Secretary of State for Environment, Food and Rural Affairs)

“On what legal or contractual basis would a data centre be required to reduce or stop using water before household and agricultural users during a drought; who would decide when that applied; and will that basis be published before planning permission is granted for further data centres?”

Follow-up: Not yet asked, so far as we know. A freedom of information request via WhatDoTheyKnow for any internal advice on data centres and drought planning would be a useful parallel step.

3 more question(s) on the in-depth page.

Ask: Kanishka Narayan MP, Minister for Artificial Intelligence (Cabinet Office and Department for Business, Innovation, Science and Trade), asking that it also be put to the Secretary of State for Energy Security and Net Zero

“Will the Government introduce mandatory reporting of energy and water use by individual data centres in the United Kingdom, published site by site, and will it ensure that such figures are not withheld from the public on grounds of commercial confidentiality?”

Follow-up: Not yet asked, so far as we know. A request via WhatDoTheyKnow to the Department for Energy Security and Net Zero for any assessment of mandatory data-centre reporting, and of the EU scheme, could follow the reply.

Ask: the Welsh Government Cabinet Secretary responsible for climate change and the environment

“Will the Welsh Government require operators of data centres in Wales, through planning conditions or otherwise, to publish each year their energy use and their water use, including peak-month water use, for each site; and what information on the energy and water use of individual data centres in Wales does the Welsh Government or Natural Resources Wales currently hold?”

Follow-up: Not yet asked, so far as we know. A request via WhatDoTheyKnow to the Welsh Government and to Natural Resources Wales for the information they hold could be made at the same time.

What you can do

  • Find the application on your council's planning website, and check what the documents say on this issue, or whether they are silent. See Start here.
  • Send the questions on this page in writing and keep copies.
  • If information is missing, ask for it through WhatDoTheyKnow.
  • Ask your town or community council to raise the issue in its response.
  • List your group in the campaigns directory so others can find you.

Read this issue in depth

Sources

  1. techUK, Understanding data centre water use in England, 18 August 2025. The report's published summary confirms a voluntary survey of 73 facilities, the 51% figure for waterless cooling, and that 64% of responding sites used less than 10,000 cubic metres (10 million litres) a year; the other percentages quoted in the text have not been re-checked against the full report. https://www.techuk.org/resource/techuk-report-understanding-data-centre-water-use-in-england.html
  2. Computer Weekly, TechUK report on datacentre water usage habits criticised, 12 September 2025. https://www.computerweekly.com/news/366630713/TechUK-report-on-datacentre-water-usage-habits-criticised
  3. Times, Surge in data centres set to push water bills even higher, 10 May 2026. Full Fact has since explained that the 14 million litres a day figure is Water UK's estimate of average peak demand, such as on hot summer days, and that average daily use is around 6.6 million litres: https://fullfact.org/environment/times-water-data-centres/
  4. North Wales Rivers Trust, 'The Menai Data Centre: At What Cost?' (September 2026), summarising the Environmental Statement for Gwynedd Council application C25/0740/20/EIA. https://northwalesriverstrust.org/news/the-menai-data-centre-at-what-cost
  5. Global Action Plan research reported in Water Magazine, '84% of Proposed UK Data Centres to be Built in Water-Stressed Areas' (27 April 2026). The original research is Global Action Plan, 'Report reveals majority of new data centres planned for water stressed areas' (7 April 2026), which puts the figure at 84% of water-intensive data-centre developments proposed for areas that are already water-stressed or projected to be so by 2040: https://www.globalactionplan.org.uk/insights/news/report-reveals-majority-of-new-data-centres-planned-for-water-stressed-areas
  6. National Infrastructure Commission for Wales, 'Wales Infrastructure Assessment 2026: Water' (March 2026). https://nationalinfrastructurecommission.wales/water26/
  7. Department for Environment, Food and Rural Affairs, 'United Kingdom Food Security Report 2024: Theme 2: UK Food Supply Sources' (11 December 2024). https://www.gov.uk/government/statistics/united-kingdom-food-security-report-2024/united-kingdom-food-security-report-2024-theme-2-uk-food-supply-sources
  8. DatacenterDynamics, report on the Humber Tech Park planning application, North Lincolnshire (18 May 2024). https://www.datacenterdynamics.com/en/news/humber-tech-park-lincolnshire-uk-district-heating/
  9. Welsh Government, Well-being of Future Generations (Wales) Act 2015: The Essentials. https://www.gov.wales/well-being-future-generations-act-essentials-html
  10. Investigate Europe / AlgorithmWatch / Corporate Europe Observatory, 'Copy, paste, govern' (17 April 2026). https://algorithmwatch.org/en/copy-paste-govern-microsoft-ghostwrote-eu-policy/
  11. European Commission, 'Making data centres energy efficient thanks to a new EU rating system' (21 September 2026). https://commission.europa.eu/news-and-media/news/making-data-centres-energy-efficient-thanks-new-eu-rating-system-2026-09-21_en