Legionella and water safety

Legionnaires’ Disease is caused by legionella bacteria, which are found in the natural environment and may contaminate and grow in water systems, including domestic hot and cold-water systems.

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Legionella and water safety

Legionnaires’ Disease is caused by legionella bacteria, which are found in the natural environment and may contaminate and grow in water systems, including domestic hot and cold-water systems.

The bacteria survives in low temperatures and thrives between 20-45°C if the conditions are right.

To help us keep you safe, do not adjust the settings on your boiler or hot water system as these are set so your water is heated up enough to kill the bacteria.

Please follow our safety advice to help prevent this bacteria in your home.

Safety advice

Ensure you turn on unused taps and showers and flush toilets at least once a week, including your outside tap if you have one.
Clean, descale and disinfect your shower head at least every 3 months. (If you do not use your shower regularly, ensure it is turned on for at least five minutes each week).
If your home has been empty for over 7 days flush your toilet twice and run your taps and shower for five minutes to flush the hot and cold water systems.

Tell us immediately if:

Your boiler or hot water tank are not working properly - especially if the water is not coming out hot once the tap has been run for one minute.
The cold water is still running warm after you have initially run off any water which may have collected in the pipes.
The water is discoloured or contains any debris.

For more information

Health and Safety Executive website