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Luton Borough Council

Legionella and water hygiene


A clean water supply is vital to your health and wellbeing. Find out how to help prevent problems arising in your home.

Most water systems contain bacteria and other organisms. If these are allowed to multiply they can cause people to become ill. The most common and high risk bacteria is legionella. 

What is legionella?

Legionella bacteria are common and can be found naturally in water sources such as rivers, lakes and reservoirs. They can survive under many environmental conditions, and temperatures between 20ºC and 45ºC encourage their growth.
Legionella is transmitted by inhalation of mist droplets containing bacteria.

Diseases caused by legionella

The legionella bacteria can cause a range of pneumonia-like diseases in people; from the less severe to the most serious – Legionnaires’ Disease. Although everyone is susceptible, some people are at a higher risk, including, but not limited to, those with a compromised immune system and the elderly.
Follow this link to the Government’s Health and Safety Executive to read more about diseases caused by legionella and the symptoms.

Is my home at risk from the legionella bacteria?

Legionella bacteria can breed in other places where water is stored, such as water systems and water cooling towers.
The risk in your home is low because your water is usually stored in small quantities at temperatures above 45ºC and is used daily. This means that the bacteria do not usually have time to grow to significant levels.
Risk can increase if a property has been empty for long periods of time, for example when tenants leave and the property is not immediately re-let.
Risk can also increase when you go on holiday for a week or more.

What can I do to prevent legionella outbreaks?

To help keep yourself and your family safe follow this guidance:
  • store hot water between 50ºC and 60ºC. The thermostat on your hot water cylinder (where applicable) will have been set to this temperature when you moved in. Combination boilers provide hot water directly to the taps without the need for a storage cylinder
  • if your property is empty for over a week, you should turn on your boiler/water heater and run the hot water for 10 minutes when you get back. This does not apply to homes with combination boilers
  • clean showerheads and hoses every three months by removing the head of the shower and cleaning it in hot water
  • ensure that you turn on taps (including any in your garden) each week for at least two minutes

What to do if you suspect legionella

If you suspect you have any legionella disease we advise you to seek medical attention. Council tenants should also call our Building and Technical Services on 0800 014 7333.
© 2023 Luton Council, Town Hall, Luton LU1 2BQ