A detailed assessment of all water related plant to check whether conditions are present which will encourage bacteria to multiply. Recommendations are made which will help prevent exposure to legionella bacteria. The survey would include a survey of all associated water plant including cold water storage cisterns, hot water calorifiers and pipework. Up to date schematics may be required.

The HSWA 1974 and COSHH contain requirements concerning the risk of exposure to legionella bacteria. Employers and those responsible for a building are required to identify and assess the foreseeable risk of exposure to legionella bacteria from work activities and water systems on the premises and evaluate a means by which to safeguard staff or members of the public from potential exposure.

Low concentrations of legionella bacteria often occur naturally in environmental water sources such as lakes, rivers and reservoirs. The bacteria may colonise manufactured water systems and be found in cooling towers, hot and cold water systems and other plant which uses or stores water. Water temperature and nutrients may create favourable conditions increasing the risk from Legionnaires’ disease.

Legionnaire’s disease is a potentially fatal form of pneumonia caused by legionella bacteria. The disease is normally contracted by inhaling legionella bacteria usually in water droplets which are small enough to penetrate deeply into the lungs.

The results of the assessment should be recorded and reviewed regularly (at least every 2 years) and whenever there is a reason to suspect that the assessment may no longer be valid.