Media Release 18 May 2020

Warning about Legionnaires’ outbreak after COVID-19

The Master Plumbers and Gasfitters Association of WA is warning about a potential outbreak of Legionnaires disease just when the economy is starting to recover from the COVID-19 lockdown.

Legionnaires' disease is a severe form of pneumonia caused by Legionella bacteria, which thrives in stagnant or slow moving water.

CEO Murray Thomas said, “As the COVID-19 lockdown restrictions ease, it is important that business owners ensure the safety of their building’s plumbing, air conditioning cooling towers and water cooling systems before occupancy resumes.”

This warning applies to all office buildings and other commercial premises that have been empty or only partially used during the lockdown.

Mr Thomas said, "Any water system that has been unused, unmanaged or unmaintained is an ideal breeding ground for Legionella bacteria."

In addition to the risk of Legionnaires’ disease from stagnant or low-flowing water, there is also the risk of gastrointestinal infections and skin infections such as those caused by fungi and Pseudomonas bacteria. There may also be excessive amounts of heavy metals.

A bad or gone-off taste, an unpleasant odour, or slight discolouration are features of water stagnation that could indicate bacteriological growth and pipe corrosion. However, it is possible for water be contaminated without any noticeable difference in taste or appearance.

Mr Thomas said, “Business owners and building managers should act quickly to ensure their building’s water supply is thoroughly flushed before occupancy resumes. The work should be done by licensed plumbing contractors and there is a database of these in the Find a Master Plumber section of the Association’s website at"

Information about flushing procedures is in the Australian Building Codes Board Advisory Note Ensuring the safety of your building water system post COVID-19 restrictions, which is in the Resource Library on the Australian Building Code Board's website at

The WA Government’s Code of practice - Prevention and control of Legionnaires’ disease is available in the Publications section of the Department of Mines, Industry Regulation and Safety website at