A Legionella risk assessment is a site-specific document that details the findings of an examination of the entire water system within the premises. The primary purpose is to identify if there are any parts of the system that might support or enable the growth of the Legionella bacteria and therefore present a risk by contaminating the system.

The assessment takes into account the following factors:

• Water Temperature
• Water Stagnation
• Potential for Aerosol Fomation
• Heat Gain / Loss Potential
• Condition of the Water
• Condition of the Water Service and the Water System as a whole.
• The Susceptibility of Exposed Persons
• The Population Density of Exposed Persons