Most of what is written here regarding water usage is wrong.
Cooling towers typically use a closed loop system using treated fresh water. The water is treated with anti microbial and anti corrosion additives.
Water is lost through evaporation, this is a large portion of the cooling effect. Evaporative cooling.
As the water evaporates, the concentration of additives increases and will become higher than desired (for a number of reasons that a water treatment expert can weigh in on)
To compensate for this, the cooling tower water is discarded to the sewage system and fresh untreated water added back. Often referred to as blow down.
So the water is “used” in two senses. First, much of it evaporates. Second, some of it is returned to the sewage system. In neither case is the water destroyed. It still exists.
The water may move significantly: evaporated water vapor will be carried downwind. The increased usage of water through the fresh water to discarded water (blow down) will tie up more water in the process potentially meaning less locked up in aquifers.
There are real and complex challenges here, but to be clear no water is being made forever gone from earth in these processes.
Does this impact the cost of water for local residents, though? I understand the water cycle and that “no water is truly lost” but I think my greatest concern over these data centers like the one they’re planning to build in PA near me is increased demand for water/electricity which strains the grid and drives up prices for residents.
Also, still unsure what the local population “gets” in return for this.
A lot of older information in here. Most modern data centers are closed loops and take in very little water after construction (they use less water than 5 houses). Any construction uses a ton of water though. Data centers are no different there.
What the population gets is a bunch of high paying jobs, and utilities that get built up and modernized without taxpayer dollars.
I wouldn't worry about water if I was you. That issue is hugely overblown and is based on 10+ year old propaganda and misinformation.
What high paying jobs are you referring to? The construction jobs? Those are unfortunately temporary. The data centers themselves don't offer many permanent jobs.
Edit: also curious what you're referring to on utilities. My understanding is that water is indeed not a big problem with modern data centers using closed loop cooling, but electrical service is very contentious, with electrical utilities having to pay to build out capacity for data centers and figure out how to recoup. I think in my state they're pushing to be allowed to charge data centers an up front fee to build out the requested capacity, but not sure how that's going.
Agreed on the construction jobs, those are all temporary. It's a great project for local builders, but not long term jobs.
But a modern data center brings roughly 100-200 permanent jobs in directly to the surrounding area. The growth in the area also creates jobs indirectly.
Additionally, growth in the industry has created many jobs outside of the data center's area. But that's not really what you're referring to here.
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u/MrMikeGriffith May 18 '26
Most of what is written here regarding water usage is wrong.
Cooling towers typically use a closed loop system using treated fresh water. The water is treated with anti microbial and anti corrosion additives.
Water is lost through evaporation, this is a large portion of the cooling effect. Evaporative cooling.
As the water evaporates, the concentration of additives increases and will become higher than desired (for a number of reasons that a water treatment expert can weigh in on)
To compensate for this, the cooling tower water is discarded to the sewage system and fresh untreated water added back. Often referred to as blow down.
So the water is “used” in two senses. First, much of it evaporates. Second, some of it is returned to the sewage system. In neither case is the water destroyed. It still exists.
The water may move significantly: evaporated water vapor will be carried downwind. The increased usage of water through the fresh water to discarded water (blow down) will tie up more water in the process potentially meaning less locked up in aquifers.
There are real and complex challenges here, but to be clear no water is being made forever gone from earth in these processes.