Legionella are a species of bacteria that cause a potentially fatal form of pneumonia, Legionnaires' disease.
Legionella is bacteria commonly found in natural water courses such as rivers and ponds. Since legionella bacteria are widespread in the environment, they may contaminate and grow in other water systems such as cooling towers and hot and cold water services.
They survive low temperatures and can live and multiply in water temperatures between 20oC and 45oC, particularly if there is stagnant water and a supply of nutrients present such as rust, sludge, scale, algae and other bacteria.
High temperatures of 60oC and over will kill them. Legionella bacteria can cause a form of pneumonia called Legionnaires’ disease, as well as other less serious illnesses.
This guide explains, in general terms, what legionella is and outlines some of the simple precautions you can take to control those risks.