The cheapest (and worst) option is to take in water, use it for cooling and then dixcharge it. Why is this bad? Because DCs don't want to corrode their pipes with untreated water so they add coolant and additives to it, which pollute the water. This is bad. But nobody really does this because you don't want to keep adding additives to water you're constantly discharging.

The next step up are varying degrees of what's called "closed loop" cooling. That is, the DC has treated water in a closed loop that isn't discharged. There's a heat exchange system with external water. This btw is the system that's used in nuclear reactors although nuclear reactors will be far more stringent than DCs are. Best practice for this is one of Google's DCs in Scandanavia that uses ocean water for heat exchange. There are limits to this but there's only so much Arctic Ocean water a DC can meaningfully heat. It is potentially disruptive though and that needs to be considered.

Even so pipes will need to be cleaned. There is debris that builds up and in cases like this you can still get bacterial outbreaks. This is another reason to use additives like chlorine. But again, you don't want to discharge chlorine into bodies of water.

I'm reminded of water management in the Yukon. The Yukon for over a century have been gold fields. If you look at the tech required to extract a tiny amount of gold from a large amount of earth, it's kind of fascinating but it boils down to using a lot of water and having the denser gold sink and get trapped.

So gold miners take in water from rivers, wash rocks with it and then have historically just discharged it back into the rivers. This tended to be heavy in silt that would go into waterways and could create problems. The water was also dirty. So the Yukon authorities have gotten increasingly stricter with water management. Now water has to go through a series of settling ponds so the discharged water is clean/clear.

I kinda think we need similar levels of strict water management for DCs. No discharged coolants and clean water. Figure out how to get that. If that makes your DC more expensive then that's a "you" problem.

I guess 'turning the entirety of the American public against data centers' is not something they factor into the cost analysis.

https://techcrunch.com/2026/06/29/omen-ais-plan-to-optimize-...

Hey where’s that person from yesterday who argued with me over the 1m vs 1cm hole in the boat?

Everyone saying stop talking about data center water use is missing the entire point as this article shows.