Potential sources of such contaminated water include cooling towers used in industrial cooling water systems as well as in large central air conditioning systems, evaporative coolers, hot water systems, showers, windshield washers,[8] whirlpool spas, architectural fountains, room-air humidifiers, ice making machines, misting equipment, and similar disseminators that draw upon a public water supply. The disease may also be transmitted from contaminated aerosols generated in hot tubs if the disinfection and maintenance program is not done rigorously.[9] Freshwater ponds, creeks, and ornamental fountains are potential sources of Legionella.[10] The disease is particularly associated with hotels, fountains, cruise ships and hospitals with old, poorly maintained pipework and cooling systems. A study published by the European Journal of Epidemiology points to automotive windshield washing systems as a source, recommending the addition of an antibacterial agent to the system's reservoir.[11]
A recent research study provided evidence that Legionella pneumophila, the causative agent of Legionnaires' disease, can travel airborne at least 6 km from its source. (3.72822 mi.)
According to the journal Infection Control and Hospital Epidemiology, hospital-acquired Legionella pneumonia has a fatality rate of 28%, and the principal source of infection in such cases is the drinking-water distribution system.