Legionnaires’ disease Part 2: The control of legionella bacteria in hot and cold water systems

The guidance gives practical advice on the legal requirements of the Health and Safety at Work etc Act 1974, the Control of Substances Hazardous to Health Regulations 2002 concerning the risk from exposure to Legionella and guidance on compliance with the relevant parts of the Management of Health and Safety at Work Regulations 1999. This guidance is for dutyholders, which includes employers, those in control of premises and those with health and safety responsibilities for others, to help them comply with their legal duties. It gives practical guidance on how to assess and control the risks due to legionella bacteria. Any water system that has the right environmental conditions could potentially be a source for legionella bacteria growth. There is a reasonably foreseeable legionella risk in your water system if: ■ water is stored or re-circulated as part of your system; ■ the water temperature in all or some part of the system may be between 20–45 °C; ■ there are deposits that can support bacterial growth, such as rust, sludge, scale and organic matter; ■ it is possible for water droplets to be produced and, if so, if they can be dispersed; ■ it is likely that any of your employees, contractors, visitors etc could be exposed to any contaminated water droplets