Data centres ‘may have used as much water’ last year in Ireland as more than 340,000 homes

Data centres may have consumed as much water in Ireland last year as about 340,600 homes, some 18.5 per cent of the total number of occupied dwellings in the Republic, researchers have estimated in a new report.Co-authored by academics from Maynooth University (MU), University College Dublin (UCD), and Universitat Autònoma de Barcelona (UAB), the report uses publicly available data to outline “the widespread costs” of data centre development and its “disproportionate drain on public resources”.Earlier this year, a United Nations report estimated that data centres have a total water footprint of 4.5 trillion litres, equivalent to the annual basic water needs of 600 million people in sub-Saharan Africa. The report also described the Republic as “a live cautionary example” to other countries of energy demand running in advance of infrastructure.Ireland has seen a sharp increase in the amount of data centres in operation in recent years, but are they necessary for economic growth? Video: Enda O'Dowd Applying that method to the Republic, using energy consumption data from the Central Statistics Office, the researchers estimate that the total water footprint of the electricity consumption of data centres was approximately 125.9 million litres of water a day in 2025, with a total annual footprint of 46 billion litres.READ MOREThe calculation assumes that there were approximately 85 active data centres in the Republic.This is equivalent to the total direct water consumption of some 340,600 homes or 18.5 per cent of occupied dwellings in the State, based on 2022 Census figures. [ Households ‘put on the hook’ for cost of data centre expansion to electricity gridOpens in new window ]However, the report warns that academics must use publicly available data because tech companies have resisted and lobbied against “even basic environmental disclosures” at the EU level.Patrick Bresnihan, associate professor at the School of Geography at Maynooth, co-authored the report with Séan Fearon, a research fellow at UAB’s Institute of Environmental Science and Technology, and Patrick Brodie, assistant professor at UCD’s School of Information and Communications Studies.Bresnihan told The Irish Times that the quality of information available to the public and academics would be improved if the Government transposed the EU’s energy efficiency directive into legislation. The Government missed the October 2025 deadline for the directive, which makes sustainability performance reporting mandatory for data centre operators.“Then we could do a proper total, but I would be pretty sure it would be close enough to that,” Bresnihan said. He said that given that data centres accounted for almost a quarter of the electricity consumed in Ireland last year, up from 5 per cent in 2015, the water usage estimate “is probably not far off”.The research also takes aim at a KPMG report, commissioned by the Government, setting out the economic case for data centres in the Republic.Published in late May, the report made several controversial claims, including that data centres support about 876,000 jobs, about one-third of total employment in the Republic. Should Ireland share its corporation tax bonanza with the EU?The researchers said that this figure is based on “spurious methodology” and a “misreading of national accounting data”. Using the KPMG report’s method, if a hospital is within 50km of a data centre, “then the activities of surgeons and paediatricians with clear and urgent social use value are assumed to be dependent on this specific data centre”, according to the research.[ ‘Nothing underhanded’ in department’s changes to data centre report, says MinisterOpens in new window ]“It will come as some surprise to medical professionals in Ireland that many of them are ‘dependent’ on nearby data centres for their life-saving work, whilst others are not.”In reality, the researchers calculate that data centres employ about 3,300 people in permanent roles in the Republic and use 23 per cent of the economy’s electricity. It means that employment in the data centre sector is 776 times more power-intensive than a job in education, 1,217 times more so than a job in construction, and 1,529 times more electricity-intensive than a job in the health, residential and social care sectors combined.