What is Legionella?

Legionnaires’ disease is a potentially fatal form of pneumonia caused by the inhalation of small droplets of contaminated water containing Legionella. All man-made hot and cold water systems are likely to provide an environment where Legionella can grow.

Where conditions are favourable (ie suitable growth temperature range; water droplets (aerosols) produced and dispersed; water stored and/or recirculated; some ‘food’ for the organism to grow such as rust, sludge, scale, biofilm etc) then the bacteria may multiply and therefore increase the risk of exposure. The organism will colonise both large and small systems so both require risks to be managed effectively.

Certain people are more at risk from Legionella bacteria than others, such as those aged over 45, smokers and people with existing illness or weak immune systems.