The potentially deadly Legionnaires disease is lurking in many household showers, a new study has found.

Researchers took 68 samples from domestic showers across Adelaide and found 75 per cent were colonised with Legionella.

Flinders University microbiologist and lead author Harriet Whiley says elderly residents, lung disease sufferers, and heavy smokers are most at risk of contracting the disease.

“It’s particularly significant given our increasingly ageing population when you consider the growing number of elderly residents who wish to remain in independent living so they can stay a part of their existing communities for longer,” Dr Whiley said.

Legionnaire’s disease occurs when a person breathes in contaminated water or dust, and the corresponding bacterial lung infection causes symptoms like fever, chills, shortness of breath and coughing.

In the most serious cases, it can be fatal.

Dr Whiley said the study highlighted a lack of public awareness about the risks associated with Legionella contamination, proving the need for public health campaigns to inform vulnerable people how they can reduce the risk.

“Simple steps can be taken like increasing your hot water temperature and running showers every week to replenish the water sitting in pipes,” she said.

A hot water temperature above 65C is recommended to kill the bacteria.