Legionnaires and Your Plumbing

Legionnaire’s disease is a type of bacterial infection which may involve pneumonia.

Signs and Symptoms: 

The first symptoms of Legionnaires’ disease are non-specific flu-like symptoms including fever, headache and muscle aches. There may also be a mild cough with or without phlegm. Some people may develop diarrhoea, vomiting and abdominal pain. The illness usually progresses rapidly and the chest infection (pneumonia) symptoms become obvious, with high fever, shortness of breath and chest pain being typical symptoms.

How do you get Legionnaires Disease?

You usually get it by breaking in mist from water that contains the bacteria. The mist may come from hot baths, showers and air conditioning units. The bacteria does not spread from person to person.

Reducing the risk of Legionnaires

You can reduce the risks of legionella infection Legionnaires disease by taking some simple steps when installing and maintaining water pipes, plumbing fittings and some water filled appliances and fixtures such as hot water systems, including solar, rainwater tanks, bores, pools, spas and air conditioners. Care should also be taken when handling soil and potting mix, and after flooding.

Hot water systems

Hot water systems, shower roses, hot water taps, hot water tanks, pipework and the associated fittings have the potential to harbour the Legionella bacteria where there may be stagnant or warm water up to 50°C.

Hot water tanks are required by Queensland law to store water at 60°C or more to reduce the risk of Legionella multiplying in the hot water system and plumbing.

However this temperature may cause scalding so water used for washing and bathing should be delivered at 45-50°C through the use of water temperature controllers such as a tempering valve.

Do not turn down hot water systems.

  • Hot water systems should not be turned off unnecessarily.

  • Boosters for solar hot water systems should not be turned off during cloudy days.

  • Hot water systems that are turned on after prolonged absences from home should heat water to 60°C for at least half an hour prior to use of the hot water.

  • Maintain your hot water systems. Use a licensed plumber and refer to the manufacturer’s instructions or check the manufacturer’s website for information.

Do you have a Private water supply such as a rainwater tanks or bore water?

Private water supplies may encourage the growth of Legionella in their storage or reticulation systems.

Watch for elevated water temperature, high organic or mineral content in the water, or accumulated sediment in storage tanks.

Rainwater tanks need to be well designed and carefully cleaned and maintained to reduce the risk of Legionella.

Cheryl Moyle