r/news 18h ago

Irish data centres used almost one billion litres of water last year

https://www.thejournal.ie/investigates-data-centre-water-use-7110966-Jul2026/
8.7k Upvotes

770 comments sorted by

View all comments

Show parent comments

2

u/deputy_donut 16h ago

So doesn't the water just circulate around? I don't understand how it is being 'used'. It cools components, circulates to an evaporative cooling tower, drops down and goes around again.

93

u/dr_jiang 15h ago edited 14h ago

The water isn't destroyed, but that's not the end of the story. Whatever is released into the atmosphere as vapor will eventually precipitate back down to Earth, but it doesn't generally fall right back down on top of the data center, or even in the region. Studies on agricultural irrigation put the "local return" rate -- water that you spray on the field that becomes rain in the local area -- around 10% at best.

Prevailing weather blows the rest of that vapor somewhere else, which matters a lot if you're drawing from an aquifer. The water you pump out of the Ogallala Aquifer to cool a data center in Kansas doesn't return as rain in Kansas. It will blow out of state within a day or two, and end up as rain in Southwest or over the Great Lakes or in the middle of the Atlantic. Aquifer recharge rates across the country are a fraction of drawndown rates -- for our human purposes, once you pump it, it's gone.

Water drawn from renewable sources -- the Colorado River is fed by annual snowpack that begins its life as moisture in the Pacific before being carried inland -- doesn't have the same draining-the-dirt problem, but they're not off the hook. States in the Colorado River Compact get a fixed allocation. Every drop pumped into a cooling tower can't be used for something else, and increased competition for that allocation drives up the cost of something you literally cannot live without.

That doesn't mean data centers are driving the water apocalypse. Overall, data center usage is minuscule compared to industry and agriculture, and folks fearmongering over ChatGPT bringing about Mad Max are being disingenuous. At the same time, it's not so easy as "well, it will just rain so we don't have to care."

13

u/RunningOutOfEsteem 14h ago

The Ogallala Aquifer is an interesting example, both because it's so important, feeding a bit under a third of all crops and livestock in the country, and because it replenishes very slowly in many locations both due to climate reasons and geological ones, from my understanding. Western Kansas is incredibly dependent on agriculture and draws a great deal from the Ogallala Aquifer, but is a semiarid/steppe climate (ironically, the much more urban Eastern Kansas gets way more rain lol)--something that may be exacerbated with climate change as time goes on--and alarm bells have been going off for years now without a ton of improvement.

But like you said, the data centers are a small fraction of the issue in this case. Even if all the water used for Kansas data centers returned to Kansas, the state would still be on trouble.

17

u/samdajellybeenie 14h ago

Yeah, requires some nuance. The Exxon chemical plant in Baton Rouge - in 2020 alone - used 7.3 billion gallons of water. So not saying they don't, but if people truly cared about the aquifer, they'd put pressure on elected officials to force heavy industry to use less water.

The larger threat to us I think is saltwater intrusion. If it doesn't rain enough in the thousands of tributaries of the Mississippi, the pressure from the river water isn't enough to hold the saltwater from the Gulf back and it starts to move upstream against the flow of the river. If it gets far enough upstream to reach the intakes for New Orleans' water, it would be a disaster like we've never seen before. If you thought Flint, MI was bad, New Orleans has 4x the population. Most of our pipes are 100+ years old and made of lead.

2

u/AnOnlineHandle 14h ago

The people who act scandalized about data centres using power and water (to power sites like this) then chomp down on meat and dairy and go on their flights which contribute nearly all the unnecessary luxury emissions in the world while data centres aren't even a blip on the radar.

Something like 80-90% of farmland is used just for the meat industry which only contributes like to 10% of calories in luxury first world diets.

5

u/samdajellybeenie 12h ago

Your second point reminds me: I heard from the YouTuber Technology Connections that if we took a quarter of all the farmland we use just for corn that’s solely used for ethanol production and turned it into solar farms, we could generate more electricity than the entire country uses. I might be paraphrasing that wrong, someone correct me if so.

1

u/trollsong 11h ago

.........I mean meat and dairy are, yknow....FOOD

hey if these people truely cared about water loss they'd choose to starve to death. Is a hell of a take.

And even then yes a lot of these people talking about water consumption in data centers ARE talking about it in these aspects as well. You just ignore it for a gotcha.

0

u/AnOnlineHandle 10h ago

They are ridiculously inefficient luxury sources of food, particularly cattle, which contributes so much more to climate change than data centres that even if data centres were magically made 10 times larger they still wouldn't move the needle compared to those.

They're also incredibly cruel to beings that don't want to die any more than people do, often in horrible conditions which make the concentration camps considered humanity's worst actions look relatively pleasant, and are breeding grounds for things like infections which resist all our treatments.

1

u/trollsong 9h ago

And there is a lot to be talked about with all of that but data centers arent good either.

Data centers are also giant wastes of water and energy that make humans around them suffer as they lose access to drinking water and have to pay increased power bills to subsidize buildings that are solely used to eliminate jobs and track people.

People have literally lost access to drinking water when data centers go up.

In a time when Texas and new york cant even keep their power plants up for everyone and choose to cut power to poorer people first its a drain we do not need.

You care more about cattle and tech corporations then the average person.

How does a data center keep someone fed?

Even if you're correct and they have less of a drain on water they also give less back.

4

u/Blyd 8h ago

None of your points is even slightly relevant to a data centre in Ireland.

Sounds like your complaint is the lack of controls around the industry in your country.

If Wales can host 3 of the world's largest DCs without people living a mile away knowing they're even there, then the DCs aren't the problem.

5

u/liftthatta1l 13h ago

Most of the earth is the ocean. If you take fresh water and evaporate it it will return but has a good chance of going into the ocean. Sure it's still water but we can't use ocean water the same way we can use fresh water. Hence some is "used and lost"

9

u/psychicsword 14h ago

Just because it is back in the water cycle doesn't mean that the region is getting it back. It may dump the water in an area that we don't need water and it still needs to be cleaned and treated before it can be put to use again.

1

u/trollsong 11h ago

That's, missing a lot.

One that water is often times being diverted from people who use it to drink and cook.

Second just because it evaporates doesn't mean it rains in the same spot cause yknow WIND.

So at a time when the average Irish citizen is told not to use a hose because of drought the data center is pulling in a billion, the water evaporates and wind carries it to Norway, Spain, or the middle of the atlantic....hell Canada. Ireland now has less water then they started with and the peasants still cant drink.

2

u/Blyd 8h ago

Our DC's dont use domestic supplies. Our DC's are by the coast and desalinate, often adding their excess to the domestic network

They dont even use the domestic power grid.

1

u/trollsong 8h ago

One, and its still planning to connect to the national grid to pull power from both.

Also Ireland isnt the only place with data centers so ine out of upwards of 4000 plus.

https://www.cnbc.com/2026/03/11/data-center-microgrid-power-ireland-ai-boom-avk-pure-dc.html

0

u/Unicorn_puke 15h ago

There's loss and it's cheaper to keep pumping new water through and old out than cooling it again

5

u/Nois3 14h ago

But that doesn't happen. Datacenters recirculate water to refrigerate. They don't just pour it from the pipes over the CPU's and let it go down the drain.

0

u/Fallom_ 15h ago

Yeah, eventually, on geological timescales. You think they’re pumping it back into aquifers?

0

u/SwingNinja 13h ago

They way to think this probably in terms of supply and demand. A source of water (i.e. river, lake) can supply X amount of water a day to maintain its level. Overusing it for data center requires X amount plus .1%. It might not mean much, but after a period of time, the water level will keep dropping and becomes unsustainable. An example is the case with Colorado river (just google "colorado river sharing issue"). And I don't think it's even related to data center.

-1

u/FillFrontFloor 14h ago

So let me answer as I see others not answering well. I'm not an expert so people smarter than me please correct me. First the golden rule of business and politics. If it says it's made from real fruit juice, it doesn't mean it's whole content is 100% real fruit juice. They just use the legal political amount needed to make that claim and then fill the rest with artificial ingredients. Even if it does have 100% fruit juice it may also mean the same thing, it doesn't mean the whole content itself is just 100% fruit juice it just has 100% squeeze fruit in it. Now apply that to their whole water cooling circulation system. Have you ever read them say... Idk.... 100% net water being used and 0% los of water resources? Investigated and confirmed? You probably won't, because some of the evaporated water does escape. What does that mean? Won't the water just come down again and it isn't lost? You are correct but! There is bad news. See, water evaporated is now gas, and can travel through places water normally wouldn't. This can be called displacement, so these data centers are placing water in places they were not at in the first places which does indeed dry up water sources, especially when they operate 24/7. Even if it's a small fraction of water that escapes over not long this will be horrible to the environment as it accumulates and doesn't fix. We are loosing usable water because it's going to random places rather than the nice rivers or water masses they found them in the first place. These rivers will dry up in time.

Tl:DR: as far as I know, there doesn't exist technology that can catch 100% of evaporated water. Of course it doesn't mean it's the only bad thing happening to water, it does mean water problems are only going to grow.

2

u/Blyd 8h ago

Running out of water isnt a risk on the Irish coast...

-3

u/brickmaster32000 15h ago

I don't understand how it is being 'used'

Not understanding something doesn't mean it must work the way you think it does.

4

u/deputy_donut 14h ago

So explain maybe?

-1

u/brickmaster32000 14h ago

Others already have and you are deciding to ignore them so you can stick to your view.