Waste heat generated by devices as a byproduct of their operation is utilized to increase and maintain the temperature of non-potable water to neutralize biological contaminants, thereby rendering such water potable. The potable water can then be utilized for evaporative cooling of the devices. A temperature sensor monitors the temperature of the non-potable water and a controller controls the pump to provide sufficient time for the water to remain in the heat exchanger above a predetermined temperature to neutralize biological contaminants and render such water potable. To the extent that different devices generate different quantities and intensities of waste heat, multiple heat exchangers are utilized, with lower intensity waste heat serving to preheat the water and, thereby, reduce the amount of time needed to reach the target temperature in a primary heat exchanger. Waste heat not utilized to generate potable water can be utilized for other heat-driven processes.