Transmission of Legionella is principally possible through contact with tap water when the Legionella enter the deep lung sections.
Not every contact with legionella-containing water leads to a health hazard. Only inhalation of bacteria-containing water as an aerosol (aspiration or inhalation, for example during showering, in air conditioners, through lawn sprinklers and in whirlpools) can lead to infection.
Drinking legionella-rich water is not a health hazard for people with intact immune systems.
Transmission of legionellosis is particularly associated with the following technical systems:
Hot water supplies (for example, in homes, hospitals, homes, hotels), air conditioning systems (air conditioning) and humidifiers
Baths, in particular hot springs (whirlpools),as well as other installations that atomize water into water droplets (for example fog generators, fog wells).