Legionella is a bacterium which causes Legionellosis, a collective term for illnesses which include Legionnaires’ Disease, a potentially fatal form of pneumonia and Pontiac Fever, a mild flu-like illness. Although the bacteria are common, in low numbers, in natural water sources, outbreaks of the illness are more common where the bacteria have grown in purpose built water systems. Awareness of the illnesses and how they are transmitted can support us in reducing the risk to people we support. Control of legionella risk is a requirement of registration with the relevant inspectorate for care services.