Automatic misting devices such as Produce Misters and Cooling Misters that spray a fine mist allows water droplets to be inhaled into the lungs which can potentially contract Legionella if the conditions are right. However, foods that are sprayed with misters can still be eaten safely. You can not be infected with Legionella by consuming the bacteria, only by inhaling it into the lungs.
With 35 years of experience designing plumbing and mechanical systems for several major architectural, engineering, and design & construct firms. He has designed plumbing, mechanical, and fire protection systems for all building types including airports, stadiums, industrial manufacturing facilities, office buildings, commercial and retail buildings, hospitals, laboratories, prisons, jails, hotels, apartment buildings, military projects, high rise and educational facilities.
Decorative Fountains spray a fine mist that can be inhaled into the lungs. If the water is not properly treated it can develop high levels of Legionella bacteria. Fountains that spray water at great heights can allow the wind to carry the water droplets a greater distance from the fountain. The greater distance traveled allows the potentially contaminated water to affect a larger population without any knowledge of water vapor being present.
Mechanical Cooling Towers as well as Evaporative Coolers and residential or light commercial Swamp Cooler / Evaporative Coolers use fans to move air through a recirculated water system, which is called drift. Drifting allows for water molecules to be dispersed into the air in considerable amounts. This vapor again can then be inhaled into the lungs which can contaminate the lungs with Legionella.
Hot Tubs can be a good breeding source for bacteria. The high temperatures and often stagnant water and piping structure can promote the growth of bacteria if the water is not treated correctly. Most hot tubs produce a fair amount of water vapor. This vapor could potentially contain dangerous concentrations of Legionella and can then be inhaled into the lungs.
Sinks or lavatories can allow fine mist of water to be released into the atmosphere if it does not have proper flow control devices on the faucet. Laminar flow faucets are preferred because they limit the velocity of water coming out of the faucet and it does not bounce off the sink basin.
Shower heads that produce a fine mist can be a hazard when it comes to Legionella. The contaminated water vapor can be inhaled deep into the lungs just from normal breathing which can then possibly lead to Legionnaires Disease.
Drinking fountains that are not used very often can have lower levels of residual chlorine or water treatment chemicals. If the Legionella bacteria builds up in stagnant branches leading to a drinking fountain then Legionella can make its way into the lungs if the person taking a drink coughs of aspirates after taking a drink.