Comment Let's not forget that this isn't necessary (Score 3, Insightful) 40
Datacenters don't need to use evaporative cooling. If municipalities choose to sell water for cheap enough that evaporative cooling costs less than alternatives, then this is on the municipalities.
Increase the cost for bulk water, and the datacenters will switch to closed loop, geothermal, whatever. If they generate the heat, they can pay for proper cooling.