Also, due to changing operating temperatures and conditions, the levels of bacteria in cooling tower water can fluctuate in a cyclical manner. The application of biocides needs to be timed appropriately. Cooling towers and evaporative condensers have both been implicated in legionnaires disease. Evaporative coolers have not. The two critical factors for domestic water services are water cleanliness and water temperature.
Dirty water provides a food supply for the bacteria.
General Design Recommendations Assume that all incoming water contains legionella bacteria. Establish the operating range of temperatures both during operating conditions and otherwise. Identify potential for aerosolization and consider the prevention thereof. Avoid long-term storage of water. Dispersal of aerosols should be away from occupied places Precautionary measures should be taken for persons of high susceptibility Insulation of cold water supply piping if the water is too warm.