It's only a waste of water if you assume the water is 'disappearing' afterward. In ontario water is mainly provided by lakes, then after treatment water is retu

It's only a waste of water if you assume the water is 'disappearing' afterward. In ontario water is mainly provided by lakes, then after treatment water is returned to the same lakes. The only waste is the power used to move/treat the water, but this is the equivalent of power used by the compressor/fan of a normal A/C anyway. The situation is obviously different if the water supply is not a closed loop, like in Australia where water is supplied from dams and then waste water in dumped into the ocean...