[scientator]

Using water to cool a data center is absolutely not equivalent to using it for farming. Once you irrigate a field, that water is gone. But if water is cooling something, then it can be collected and used again. Of course, that requires a city or county to have a water reclamation program.

Likewise, if you water a lawn, that water is gone. But if you flush water down a toilet or a shower drain, the water is potentially reusable. Just needs to be cleaned.

Waste water can also be used for cooling. I believe that's how the Palo Verde nuclear plant outside of Phoenix is cooled.

[eesmith]

"it can be collected" is far different from "is collected".

If the data center uses evaporative cooling then most of the water vapor leaves that water basin. While some of that irrigation water goes into the ground and stays in the water basin for a longer time.

Likewise, if you water a lawn - and assuming you are not so daft as to do it when the sun is high - the most of the water will go into the ground, reaching eventually the acquifer or a waterway, for eventual downstream reuse.

This is why cities in dry climates, or places facing a drought, will have restrictions like "No outdoor watering between 10 a.m. and 6 p.m."

[rmwaite]

> Once you irrigate a field, that water is gone.

This doesn't seem true to me, in the sense that anything is truly "gone". The water doesn't cease to exist or is converted to anything other than water. It just moves.

[scientator]

Right. The water isn't gone from the universe, certainly. But it's gone from the city/county water system. You've then got to wait for it to come back via the natural water cycle. Whereas it's a lot more efficient to keep as much water as possible in the human system and just keep cleaning and reusing it.