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Water safety

Legionnaires' disease

In the right conditions harmful bacteria can grow causing an increased risk of Legionnaires' disease. Legionnaires' disease is a potentially fatal form of pneumonia and can affect anybody, but there are a number of factors that increase susceptibility, including;

  • people over 45 years of age
  • smokers
  • people suffering from chronic respiratory or kidney disease
  • anyone with an impaired immune system

Legionella bacteria is most commonly found in soil and natural water courses, such as rivers, but it can also occur in man-made water systems including hot and cold water storage tanks, pipes and garden hoses. Legionella can survive in low temperatures, but thrives at temperatures between 20°C and 45°C. High temperatures of 60°C and over will kill it.

The bacteria are usually associated with larger water systems in offices, hotels and hospitals but it can sometimes be found in smaller systems such as domestic properties. If small droplets of water contaminated with the bacteria are inhaled, it can cause Legionnaires' disease. Legionella cannot be caught by drinking contaminated water, to be harmful the bacteria needs to be inhaled.

The symptoms of Legionnaires disease are similar to those of flu:

  • high temperatures
  • fevers or chills
  • headaches tiredness
  • muscle pains
  • dry coughs

Reducing the risk of Legionella in your home

Despite the above, the risk of Legionella causing illness in small domestic properties is exceedingly low. Possibly the biggest risk is when you have been away from your home. This may be due to long hospital admissions, extended holiday periods or any other reason for more than a week.

When returning to your home to help reduce the risks you should:

  • run the taps for minimum 5 minutes
  • flush the shower (to do this, remove the shower head or place the shower head in a bucket and run the shower for 5 minutes on high and low temperature settings)
  • flush toilets twice to circulate fresh water through the system and empty the cistern

Please note: When flushing taps and showers, you must take care to prevent aerosol generation.

Showers and spray taps should be cleaned of scale and debris every 3-6 months or earlier if scaling is evident.

If your system maintains stored hot water (i.e. it is not a Combi-boiler that heats the water as it needs it), the thermostat should be set at 60°C however care should be taken for older persons and children to prevent the risk of burns and scalding.

Reducing the risk of Legionella in your garden

Garden hoses can pose a risk, particularly if they haven't been drained and stored in the sun. We recommend completely draining the hose after use, storing it vertically and out of direct sunlight where possible.

Water butts should be drained and cleaned on a regular basis to prevent bacteria build up.