An elevated water tank having an improved means of preventing ice formation. The water tank is provided with an air supply line communicating the interior or the water tank to an external air compressor. The air compressor forces air through the air supply line into the water held in the water tank causing mixing of the water and generally perturbing the water to prevent ice formation on the surface of the water. The ice prevention system ensures the availability of water supply from the elevated water tank during the winter months when many water tanks freeze over. Furthermore, the ice prevention system eliminates the need for agitators and recirculation systems prone to failure or costly heating systems.