Legionella bacteria grow in warm water, and Legionella are commonly found in cooling tower reservoirs and in domestic water systems, especially in hot water systems. When Legionella grows, and Legionella-containing water aerosols are inhaled, susceptible individuals (such as older and/or immunocompromised people) may develop Legionnaire’s Disease. Control of Legionella includes water temperature control and continuous or intermittent chemical treatment of aerosol-producing sources. Aerosol producers include cooling towers, whirlpool spas, misters, fountains, aerated faucets, and showers. Prevention includes designing out points of stagnation in water systems, preventing contamination of plumbing during construction, and flushing with chemical treatment of new or modified plumbing systems prior to occupancy.
Lately, there has been a rise in outbreaks, as explained in this article published by U.S. News and World Health Report. Thankfully, more people are becoming aware of Legionella bacteria and are taking necessary steps to prevent outbreaks from occurring.