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Legionella Risk Assessment 



Legionnaire’s disease is a collective name given to the pneumonia illness caused by legionella bacteria. The bacteria are found in hot and cold water systems. Legionella is a naturally occurring bacteria which can be found in rivers, lakes and reservoirs and there are over 50 known species.




Legionella It is possible for the bacteria to enter a building’s water system such as domestic systems and their associated hot and cold water tanks, showers, cooling towers and evaporation condensers via the mains supply where it can grow. People contract Legionnaires’ disease by inhaling small droplets of water (aerosols), suspended in the air, containing the bacteria. Certain conditions increase the risk from legionella if:

  • the water temperature in all or some parts of the system may be between 20-45 °C, which is suitable for growth

  • it is possible for breathable water droplets to be created and dispersed e.g. aerosol created by a cooling tower, or water outlets

  • water is stored and/or re-circulated

  • there are deposits that can support bacterial growth providing a source of nutrients for the organism e.g. rust, sludge, scale, organic matter and biofilms

If you manage any water systems within a building, then you need to have a risk assessment and good control measures in place.  We can help you achieve this.





There are no set frequencies for an assessment, this varies depending on the type of business and premises as well as its use, size of the water system, the degree of risk and changes in the operation or design of the water system. Full details can be found at the link below.





A consultant will attend your site to undertake a Risk Assessment to assist you in complying with the Approved Code of Practice (ACoP) L8 “The Control of Legionella Bacteria in Water Systems” (Fourth Edition)


We will provide a clear and comprehensive report (Legionella Risk Assessment) including a detailed description of the water systems and a summary of the current management system in place as well as any remedial works needed quoted for.

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