To make that work you need to build your datacenter immediately adjacent to dense housing. We don’t do that in the USA. Zoning & all that.
It also sounds like more of a northern thing. Water in many parts of the US is already too warm out of the tap in the summer
Not all that energy efficient, either
Cycling data center heated water back into the municipal system doesn’t help. It would still have to go through the water treatment process which would incur additional per gallon costs without value (the water is already clean). Not to mention that water treatment plants, like data centers, create significant low-temperature waste heat themselves.
An alternative version of this is to require data centers to have their own retention system (like @Nightaudit 's suggestion that nuclear plants do), but that comes at additional cost as @engineer_comp_geek pointed out.
Use black or grey water in the datacenter’s external cooling loop.
IOW, don’t plumb them into the drinking water. Plumb them into the sanitary sewers. With appropriate screens to keep the chunky stuff out and flowing downstream. Whatever water doesn’t evaporate on the first pass through the datacenter cooling towers heads downstream to the existing sewage treatment facility.
Paging @robby for a reading on my mostly silly proposal.
I think you’re also missing how much more water you’d need to get the same cooling effect as evaporation. If your water is coming in at 60F and you return it at 90F, it’s going to take around 35 times as much water if my calcs are correct. That mid-size data center using 100,000 gallons per day now needs 3.5 million gallons/day.
If anything, this is probably optimistic for any data centers in the South, or elsewhere in summer. You probably can’t get away with much over 90F outgoing, but incoming water might be more like 70 or 80F.
You’re going to pump raw sewage onto evaporative towers? Screens or not, that’s not going to work well for a myriad reasons.
That was the proposal as I understood it. It has to go through the water treatment system – it can’t just be dumped into the clean water source. But this puts an additional load on the water treatment facility to treat already clean water (and all that entails).
Another option is dump it into the storm sewer system (or directly into nearby water), but this is textbook thermal pollution. This assumes the waste water drains into the same reservoir that it was drawn from. This is guaranteed in Chicagoland where many suburbs draw water from Lake Michigan.
Getting rid of heated water is going to be expensive with any method. I think the only cost-effective method is to find a use for the heat that offsets the add cost – like district heating, greenhouses, etc.
What would be more efficient would be to have two different water inputs into the house, one (cool) for general use, and the other (hot) feeding directly into the water heater (which now wouldn’t have to work as hard). Of course, this would add complexity.
The other complicating factor is that a lot of folks think that AI is in a bubble right now. When the bubble bursts, we’ll still use data centers, but probably not as many. But, how many, and which ones? It doesn’t make sense to build infrastructure dependent on the existence of the datacenter, if you don’t know how long the datacenter will last.
I think if you are going to run a second pipe, then you just do district heating where it acts as a heat pipe for the cold water. This eliminates the need to treat the water in the hot system.
Yeah, lots of “how to make this work” discussion but there’s less engagement on “should we do it at all”
It is very easy for the shell corp that owns it to declare bankruptcy and walk away from an unprofitable data center, hurting any external infrastructure dependent on it.
I think the only reasonable choice for non-evaporative cooling is liquid to air heat pumps (aka air conditioners). Use some electricity to pull heat out of the circulating cooling liquid and dump it into the atmosphere.
No, no, no.
I meant supply lightly filtered raw sewage to the cooling towers, then take whatever doesn’t evaporate and add it back into the sewage flowing past the center and on into the existing civic water treatment facility. So they get the same gunk they always did, just with somewhat less water mixed into the goop.
I do not mean put clean drinking water in, then dump the used water into the passing sewage flow for (re-)treatment at the civic plant.
That idea stinks.
In some areas, there are two different water inputs; one the traditional potable water for drinking and such, while the other supply is from the water treatment plant and is for non-potable use like irrigation or clothes washing.
Maybe co-locate it with an intensive hog farming operation? The neighbors might prefer a data center to another half square mile of hog barns. 
Sorry, my mistake! It’s an interesting idea.
No, you were correct. Even “lightly filtered” raw sewage is still gross.
I guess this is indeed done in certain places, especially water-stressed regions. It makes sense. Rather than treat the water all the way to drinking safety standards, tap off at an earlier stage and feed to large users. The water can be clean, but not drinkable.
Here’s a link with a few examples:
No, you’d just have a heat exchanger on the water main like I said in post #73. To reiterate, the municipal water wouldn’t mix with any of the data center water, they just pass by each other and transfer their heat via metal plates, tubes within a tube, or tubes within a tank, etc. No pumping required, no additional treatment/filtration, just a passive “thing” that doesn’t even require electricity except for some temperature probes and perhaps some valves. You’d still need to locate near a municipal pumping station, water tower, or large water main to get enough flow, and it would cause other problems, but I already mentioned those.
Sorry, I misread (or misunderstood) your post the first time through.
You can be forgiven, considering alternative proposals, like @LSLGuy ‘s plan to evaporate raw sewage