A Hawke's Bay woman has had to have her feet amputated after contracting Legionnaires' disease from her hot water cylinder.
The region's district health board also says a man in his 80s also picked up the disease in the same way.
Medical officer of health, Nicholas Jones, says the cases serve as a warning to others.
"Our main message here is for people to make sure their hot water temperature is set to 60degC because at that temperature the bacteria can't grow in the hot water," he says.
Legionnaires is a severe type of pneumonia and can be fatal.
RadioLIVE
