Ireland's Data Centres May Have Used as Much Water as 340,000 Homes Last Year, Researchers Warn
Data centres in Ireland may have consumed approximately 46 billion litres of water in 2025 — equivalent to the direct water consumption of roughly 340,000 homes, or 18.5 per cent of the Republic's occupied dwellings — according to new academic research that highlights a critical gap in transparency and regulation around the resource usage of one of the country's fastest-growing industries.
Background
Ireland has become one of the most data centre-intensive countries in the world relative to its size, driven by its position as the European hub for many of the world's largest technology companies. As of 2024, data centres accounted for 22 per cent of Ireland's electricity usage, with forecasts suggesting this could rise to over 30 per cent in the coming years. The energy implications of this concentration have been extensively debated; the water implications have received far less attention.
Data centres use water primarily for cooling — either directly, through evaporative cooling systems that consume large volumes of water, or indirectly, through the water used in the generation of the electricity they consume. The distinction matters because operators who use closed-loop cooling systems often report negligible or zero operational water consumption, while the water embedded in their electricity supply is not captured in their own reporting. The new research, co-authored by academics from Maynooth University, University College Dublin, and the Universitat Autonoma de Barcelona, attempts to capture both dimensions.
The regulatory context is significant. The EU's Energy Efficiency Directive mandates that data centres with a power demand of 500 kilowatts or higher report their annual water and energy usage. But compliance has been notably low: in the first reporting cycle, only 18 data centres — approximately 15 per cent of the estimated total in Ireland — submitted data to the European Commission. The Irish government missed the October 2025 deadline to transpose the directive into national legislation, meaning there are currently no penalties for operators that fail to report.
Key Developments
The research, published this week, estimates that the total water footprint associated with the electricity consumption of Ireland's data centres was approximately 125.9 million litres per day in 2025, resulting in an annual footprint of 46 billion litres. This figure is comparable to the direct water consumption of about 340,600 households, or 18.5 per cent of the Republic's occupied dwellings.
The researchers identified a poverty of information as the primary obstacle to accurate assessment. While Uisce Eireann previously estimated that data centres accounted for less than 0.2 per cent of national annual water consumption, the researchers characterise this figure as outdated and based on a limited count of connected facilities. The Environmental Protection Agency has reported that no data centres are currently registered for groundwater abstraction, despite the requirement for any entity drawing over 25,000 litres per day to do so — a finding that suggests significant under-reporting.
The European Union has proposed a new rating scheme for data centres — similar to energy labels for home appliances — which will rank facilities on a coloured scale from A to G based on their energy and water efficiency, with the first labels expected to appear in 2027.
Why It Matters
Ireland's water infrastructure is already under significant strain. Uisce Eireann has been investing heavily in upgrading the national water network, but leakage rates remain high and supply capacity in some areas — particularly in the greater Dublin region — is constrained. The addition of a large and growing industrial water demand from data centres, much of which is not being accurately measured or reported, complicates the task of managing the national water supply.
The United Nations has described Ireland as a live cautionary example of digital infrastructure expansion outpacing energy and resource planning. The water dimension of that warning has been less prominent than the energy dimension, but the new research suggests it deserves equal attention. The government's failure to transpose the EU directive on time has left a regulatory gap that operators have, in some cases, exploited — not necessarily through deliberate evasion, but through the absence of any requirement to measure and report their water usage accurately.
Local Impact
The concentration of data centres in the greater Dublin region — particularly in areas such as Clondalkin, Tallaght, and along the M50 corridor — means that the water implications of the sector are felt most acutely in the capital. Dublin City Council and Fingal County Council have both raised concerns about the cumulative impact of data centre development on local infrastructure, including water supply. In areas where data centres draw from private boreholes rather than the public mains, the impact on local groundwater levels is particularly difficult to assess in the absence of mandatory reporting. The Irish Water regulator has indicated that it will seek to address this gap as part of its next regulatory review.
What's Next
The Department of Climate, Energy, and Environment has stated that the process of transposing the EU Energy Efficiency Directive into Irish law is ongoing and unfinished. Environmental groups have indicated that they will seek a timeline for completion and will consider legal action if the transposition is not completed promptly. The EU's proposed data centre rating scheme, expected to be finalised in 2026 and implemented from 2027, will provide a framework for mandatory reporting that should significantly improve the quality of data available to researchers and regulators. The Oireachtas environment committee is expected to hold hearings on the issue in October.
