The District Health Board are warning people against turning down their hot water cylinders after two people contracted Legionnaires disease in Hawke's Bay.
One of the patients is still in intensive care and has had her feet amputated while the other was discharged from hospital in May.
The cause of their ailments were discovered after tests were conducted in the victims homes and the Legionella bacteria was found in both the man and woman's hot water cylinder.
It is thought one of the victims had turned down her water cylinder to save money while the other may have had a faulty thermostat.
Legionella bacteria prefer temperatures between 32 -44 degrees but can't survive in temperatures higher than 60 degrees.
The incubation period of Legionnaires' disease is from two to ten days and for several days, the patient may feel tired and weak.
Most patients who are admitted to the hospital develop a high fever and a cough can be the first sign of a lung infection.
Gastrointestinal stomach symptoms are common with diarrhea being the most distinctive symptom.
Many patients have nausea, vomiting and stomach discomfort along with other common symptoms including headaches, muscle aches, chest pain, and shortness of breath.
The Hawke's Bay DHB are advising the public to make sure they keep their water cylinders regulated at a high temperature.