Legionnaires’ Disease – A Guide For Residents

In any well-maintained block, the risk of Legionnaires’ Disease is low. However, if a block’s communal water storage tanks and supply pipes are not correctly maintained and monitored, legionella bacteria can find itself in the right conditions to grow. Here we explain what the bacteria is, how it might be allowed to multiply and what steps residents can take to reduce the risks.

What Is Legionnaires’ Disease?

Legionnaires’ Disease is a potentially fatal form of pneumonia that is contracted by breathing in small droplets of water contaminated with legionella bacteria. There are also less serious illnesses associated with the legionella bacteria called Lochgoilhead Fever and Pontiac Fever. If someone contracts Legionnaires’ Disease it is not possible to pass the infection on to another person. The symptoms of Legionnaires’ Disease are very similar to flu and include high temperature, fever or chills, headache, tiredness, muscle pain and a dry cough.

If you think you or someone you know has contracted Legionnaires’ Disease, you must consult your doctor immediately.

Where do Legionella bacteria come from?

Legionella bacteria are widespread in the natural environment and are sometimes present in very small quantities in the mains water supplied by the water companies. Although the levels are not dangerous the bacteria can take up home in hot and cold water systems in residential properties and multiply to dangerous levels.

Legionella bacteria survive at very low temperatures but thrive at temperatures between 20 and 45ᵒC. These conditions combined with a source of food i.e. sediment, scale, stagnant water and rust can provide an environment where legionella bacteria can multiply and become a problem.

Who is most at risk of infection?

While anyone can catch Legionnaires’ Disease and other legionella related infections some people will be more susceptible to infection e.g. those over 45 years of age, smokers and heavy drinkers, those suffering from chronic respiratory or kidney disease, and people whose immune system is impaired.

What should be being done in your block to control the risk?

The initial step in the control of legionella bacteria in your building is to undertake a water hygiene and legionellosis risk assessment which would be organised by your property management company. Once the risks are identified, a written scheme of control can be created and implemented. The scheme of control includes comprehensive record keeping and regular site visits to check the water system and its operation.

What can you do to reduce the risk further?

One of the key elements in keeping water clean is to keep it moving. When water stands still it warms up and starts to stagnate. This is when legionella and other bacteria move in and start to multiply. This can be avoided by running infrequently-used taps at least on a weekly basis. If you have a guest bathroom or second toilet that isn’t used very often then perhaps rotate usage. Note that flushing of showers should be done with the shower head removed in order to avoid releasing small droplets carrying Legionella bacteria.


  • Keeping all shower heads and taps clean and free from a build-up of limescale.
  • Keeping taps and showers free of bacteria, mold or algae growth using household bleach or other anti-bacterial cleaner.
  • Keeping your water hot if your system stores hot water. 60ᵒC at the cylinder is the recommended temperature but be aware of the risk of scalding.
  • Where you have your own instantaneous water heater, such as combination or condensing boiler, the temperature at the outlet should reach 50ᵒC or over within one minute of running.
  • Removing blind end pipework (pipes that do not serve an outlet) and ensure all pipework is insulated to preserve the correct hot and cold temperatures.

Finally, if you have been away on holiday for more than a week then flush all your taps for a minimum of 5 minutes. If you do go on holiday or are away for a longer period of time it is your responsibility to keep the water safe; when there is a problem in your water pipes it can migrate to other parts of the system and cause problems for other residents.

If you feel that your property would benefit from a more professional managing agent, get in touch with us today to discuss your property.

Thank you to Aqualogic for the facts and figures shared in this article.  

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