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Comment by password4321 | Hacker News Reader

I would like to know how much water is taken by a datacenter vs. the same size space of apartments. I can see why it could be considered a bad choice for communities long term if a datacenter takes more.

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The government in The Dalles, Oregon were suing local newspapers that were questioning Google's water usage in the city:

https://www.rcfp.org/dalles-google-oregonian-settlement/

Apparently Google uses nearly 30% of the city's water supply:

https://www.oregonlive.com/silicon-forest/2022/12/googles-wa...

I highly doubt any apartment block comes close to taking 30% of a city's water supply.

I’ve driven through The Dalles. It’s a very small town. A search shows a population of 15,000 and declining annually.

It’s also right on a big river. The article you linked said that Google was spending nearly $30 million to improve the city’s water infrastructure so there are no problems.

Talking about this in terms of percentages of a small town’s water supply while ignoring the fact that the city is literally on a giant river and Google is paying for the water infrastructure is misleading.

2/3rds of new data centers are built in areas of existing water scarcity.

The question was water spendinf per square meters compared to household. That question was answered and does not depend on proximity to river.

That's because it's a large industry and nobody lives there. This pattern appears all over the place. The paper mills in the pacific northwest consume large multiples of the water used by their little towns.

That's not the point, the question was whether an apartment building would use the same amount of water and clearly an apartment would consume substantially less water.

If you replace the area of that data center with apartments, as the question suggested, it would add half again to the local population, which could indeed use 30% of the city water.

I'm not understanding the logic. You want to add more population to the city? That doesn't seem fair but I'll concede I may not understand the point you're trying to make.

Assuming that the population is the same in the city and you just move residents into an apartment complex. I don't understand how you would get the same water consumption, am I missing something? Evaporative cooling is extremely water heavy and these facilities also have the normal HVAC you'd expect. Everything just seems to point to more water usage not less.

No, the question was whether "the same size space of apartments" (i.e. apartment buildings occupying the same land area as the datacenter) would use more or less water than the datacenter.

Under reasonable assumptions, the apartments would use more water.

- Google's datacenter complex in the Dalles covers ~190 acres.

- Typical density for apartment buildings is 50 units/acre, meaning you'd have 9,500 units on 190 acres.

- Average household size in the US is 2.5, so the 9,500 units would have a population of 23,750.

- According to the original article, per capita domestic water usage in the U.S. is 82 gallons per day, meaning a total water consumption of 710M gal/yr for the apartments. And this doesn't count the substantial indirect water usage you'd need to support this population.

- The Google datacenter uses 355M gal/yr (per the Oregonian article).

- 710M > 355M

Now, it would be somewhat ridiculous to replace the entire Google datacenter with apartment buildings in a rural town with declining population, but that was the original question...

Some quick napkin math using averages (data center designs vary). One of Google's larger and thirstier data centers, in Oklahoma, is said to use 833 million gallons per year (that's about 2500 acre-feet, in useful terms). It occupies about 250 acres, most of which looks to be parking lots but whatever. The number of households that can be supported on 1 acre-foot per year ranges from 2 to 6 depending (Las Vegas on one end, San Francisco on the other).

You said apartments specifically and this urban form usually starts at 50 dwellings per acre, minimum, which would lead me to say the apartments use more water. The break-even point in this equation is 2-5 households per acre.

Apples and oranges, you can compare the water usage, but places for people to live aren't in the same category as datacenters.

Yes they are. Both can be built in areas with abundant water supply.

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