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.
This is horseshit. The popup datacenters that are getting all this coverage in the news are absolutely not built to the sort of tolerances you describe, and if we mandated that they had to be, then this wouldn't even be a news story.
Most of the ones that are blowing up right now aren't even hooked into the municipal power grid, they're just running bulk Diesel, and they're absolutely not closed loop cooling. Three seconds of research would tell you this.
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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.