Information leaflet for the control of legionella in hot and cold water systems for occupiers of residential property.

We are committed to protecting the health and safety of our tenants and recognise that the risks from legionella bacteria may arise within your home. Legionnaires’ disease is a form of pneumonia caused by the legionella bacteria and can kill. Legionella are bacteria common in natural rivers, lakes and artificial water systems such as hot and cold water systems, storage tanks, pipe work, taps and showers. 

Other possible sources of legionella include spa and whirlpool baths, humidifiers, drinking water systems, water features, garden hoses and sprinklers. 

Legionella bacteria can survive in low temperatures, but thrive between 20°C and 45°C. Temperatures above 50°C will kill the bacteria. The infection is caused by the inhalation of water droplets or spray-mists which have been contaminated by the bacteria. Those most at risk include elderly people, smokers, heavy drinkers and those suffering from long term illness. It is not contracted through drinking contaminated water and cannot be passed from person to person. 

The risk is very small but to ensure legionella remains under control, always ensure you do the following: 

  • Ensure the temperature of the hot water setting on the boiler is set to at least 55 degrees (but no more than 60 degrees) and if there is a hot water cylinder ensure the thermostat is set to at least 55 degrees (up to 60 degrees) 
  • Before you move in and if you go away for more than a week heat the water to 60 degrees for at least one hour and then run all taps on full heat for at least 5 minutes. Hosed shower heads should be placed on the tray or in the bath before being turned on 
  • Tell your landlord if the hot water doesn’t heat up properly or your cold water becomes too warm. Aways report directly on Pellegrino.fixflo.com
  • Shower heads must be, disinfected and cleaned at least quarterly or more if indicated by the rate of fouling. If occupants have a long term illness, smoker, heavy drinker or elderly, cleaning should be more regular 
  • If there are any unused taps/showers/toilets for example an outside garden tap or unused second toilet with shower and/or hand basin, these must be run weekly throughout the tenancy 

Keep it clean, Keep it moving, keep the hot, hot and the cold, cold. 


Raising the temperature of warm water is one way to control legionella growth, but could also increase the risk of burns and scalding. Please take care.

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