IRELAND’S LARGEST DATA centres used close to one billion litres of water last year, a new investigation by The Journal Investigates has found.

The figures provided to the Environmental Protection Agency (EPA) and analysed by our team show how much water each data centre campus has used since 2024.

In total, at least 1.7 billion litres of water have been used by data centres from the public supply over the past two years.

More than half of this – 999 million litres – was used last year, though the vast majority of this can also be attributed to just two data centre campuses.

The amount used by data centres last year is enough water to fill 400 Olympic-sized swimming pools, or the equivalent of approximately 20,500 people’s annual water use – roughly the population of Sligo Town.

Only the largest data centres are required to report this information to the EPA each year, meaning that the true figures of data centre water use are likely higher, but the figures do provide a glimpse at how much individual campuses use.

The Journal has previously reported that the opaque nature of the industry and lobbying efforts from tech companies to keep it that way mean that there is limited environmental information on the impact of data centres publicly available.

A government study from 2022 suggested that data centres used roughly 810 million litres of water a year.

And as reported by The Irish Independent, figures provided by Uisce Éireann to Labour TD Ciarán Ahern show that the 57 data centres identified by the utility use a total of 4.78 million litres of water a day on average.

The persistent hot weather and the national hosepipe ban imposed by Uisce Éireann have led to questions about how much water data centres are using.

But our investigation shows that while huge quantities of water are being used by data centres every year, the figures pale in comparison to other sectors of the economy, namely the pharmaceutical industry.

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Data centres use millions of litres every year

At least 1.7 billion litres of water has been used by data centres connected to the public water supply since 2024, according to figures examined by our team.

The amount of water used has increased year-on-year, with it rising from 752 million litres in 2024 to over 999 million litres in 2025.

But the overwhelming majority of this can be attributed to just two data centre campuses – Meta’s campus in Clonee, Co Meath and Equinix’s campus in Dublin.

These two campuses used over 954 million litres of water between them last year – 556 million litres for Meta’s campus and 398 million litres for Equinix’s campus.

Equinix also used more than a million litres of recycled water during the year.

The remaining 44 million litres came from data centre campuses run by Amazon, Google and Microsoft.

For most other data centre campuses, their water use ranged between 1-4 million litres last year.

A spokesperson for Meta declined to comment on the company’s water use, while a spokesperson for Equinix did not respond to a request for comment.

The vast majority of these data centres are located in the Greater Dublin area, with only Meta’s campus and an Amazon data centre on the border of Meath and Louth in Drogheda located outside the capital.

In a statement issued last week, Uisce Éireann said “data centres are not a major driver of demand on the public water supply network, accounting for less than 0.3% of the water supplied.”

They added that “modern data centres use relatively small volumes of water” and that “not all data centres use water from the Uisce Éireann network.”

While some data centres analysed by our team did occasionally use recycled or harvested rainwater, all were connected to the public water supply and sourced the vast majority of their water from this.

Still not the full picture

An analysis by our team shows that 48 data centres are included in these figures and relate to the largest data centres in Ireland.

The figures provided to Ahern by Uisce Éireann cover 57 data centres, but do not provide any information per campus.

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Both sets of figures are also not the full picture of data centre water use, though the largest users are likely accounted for.

The Journal Investigates previously found 89 data centres believed to be operational, though this figure is almost certainly higher now.

Our team has also previously reported how the European Commission has collected key metrics like energy efficiency and water consumption from data centres since 2024.

But much of this information is hidden from public view, after the tech industry successfully lobbied to classify it as confidential and commercially sensitive.

It means that the environmental impact of these vast facilities remains largely secret, despite the data flowing into a publicly-funded database.

Ahern told The Journal Investigates that with two figures for the amount of water used by data centres – one from Uisce Éireann and one from the EPA – having an “accurate national figure would be really important”.

“It doesn’t seem like anyone here has a handle on exactly what resources data centres in this country are using, and that’s really quite troubling,” he added.

Without this, it’s not possible to “assess the cost-benefit analysis of this industry”, he continued, which is important if the growth of data centres in Ireland is to continue.

Water use higher in pharma plants

Though data centres use a huge amount of water every year, it is far lower than the amount used in pharmaceutical plants.

An analysis of water usage from six of these plants, again submitted to the EPA, shows that, on average, they use many magnitudes more than data centres.

Over four billion litres of water were used from the public supply by these pharmaceutical giants in the last two years – more than double that of Ireland’s data centres.

Pfizer’s plant in Grange Castle, which is surrounded by a cluster of data centres in south-west Dublin, used 1.2 billion litres of water in the last two years, matched only by Meta’s data centre campus.

Some of these plants also use other sources of water, like groundwater extraction, which involves taking water from underground aquifers, typically through wells.

Eli Lilly in Kinsale, Co Cork, for example, used 415 million litres of water sourced from groundwater extraction last year, on top of the 308 million litres they used from the public supply.

A spokesperson for the company said, “the water we use is the minimum necessary for the safe production of medicines.”

They added that they are “committed to responsible water stewardship across manufacturing operations” and “continuously invest in improving water efficiency and sustainable sourcing”.

It’s also not just the pharmaceutical industry that uses huge amounts of water.

The Aughinish Alumina plant in Limerick has used more than 10 billion litres of water producing alumina over the past two years.

Rusal, the Russian company which owns the refinery, did not respond to a request for comment.

Ahern said that everyone understands that industry will use resources, and that during this exceptional period of dry weather, water needs to be conserved.

But while the public is restricted in their water use from the hosepipe ban, he said, “large industry isn’t being asked to do anything, and no pressure at all appears, at least publicly, to be put on these industries to manage or curtail to the extent that they can their water usage.” Ahern added:

I think what people want to see is some element of fairness.

The hosepipe ban does not apply to commercial entities, like data centres or pharmaceutical plants.

Ahern also said that with data centres, the benefits aren’t as direct as they are with other industries like pharmaceuticals, pointing to the number of jobs they create and the products they produce.

“But again, it’s just about a sense of fairness that it’s the burden of climate change being placed on ordinary people as opposed to the larger corporate users who are benefiting from it,” he said.

The Journal Investigates

Reporters: Conor O’Carroll & David Mac Redmond • Editor: Noel Baker • Social Media: Cliodhna Travers • Main Image Design: Lorcan O’Reilly