Managing legionella in hot and cold-water systems

Please note if you are a provider registered with CQC, and with premises located in England, CQC is the relevant regulatory body for patient safety matters.

Legionella bacteria is commonly found in water. The bacteria multiply where temperatures are between 20-45°C and nutrients are available. The bacteria are dormant below 20°C and do not survive above 60°C.

Legionnaires’ disease is a potentially fatal type of pneumonia, contracted by inhaling airborne water droplets containing viable Legionella bacteria. Such droplets can be created, for example, by: hot and cold-water outlets; atomisers; wet air conditioning plant; and whirlpool or hydrotherapy baths.

Anyone can develop Legionnaires’ disease, but the elderly, smokers, alcoholics and those with cancer, diabetes or chronic respiratory or kidney disease are at more risk. HSE’s Legionnaires’ disease page provides information on managing the risks

Health and social care providers should carry out a full risk assessment of their hot and cold-water systems and ensure adequate measures are in place to control the risks.

The primary method used to control the risk from Legionella is water temperature control.
Water services should be operated at temperatures that prevent Legionella growth:
• Hot water storage cylinders (calorifiers) should store water at 60°C or higher
• Hot water should be distributed at 50°C or higher (thermostatic mixer valves need to be fitted as close as possible to outlets, where a scald risk is identified).
• Cold water should be stored and distributed below 20°C.

There are various systems available to supply hot and cold-water services that range in size, scale and complexity.

All can present foreseeable risk of exposure to legionella. Temperature control is the traditional strategy for reducing the risk of legionella in hot and cold-water systems. Cold water systems should be maintained, where possible, at a temperature below 20°C. Hot water should be stored at least at 60°C and distributed so that it reaches a temperature of 50°C (55°C in healthcare premises) within one minute at the outlets.

Back to News

Need some health and safety advice?

Book a free no-obligation consultation with one of our Health & Safety consultants today

Get in Touch