Legionella bacteria can cause a serious type of pneumonia (lung infection) called Legionnaires’ disease. The bacteria can also cause a less serious illness called Pontiac fever. Legionnaires’ disease is recognised worldwide as an important cause of both community- and hospital-acquired pneumonia. Legionella bacteria are common and can be found naturally in environmental water sources, including rivers, lakes, natural pools and moist soil.
It can become a health concern when it grows and spreads in human-made building water systems like shower heads and sink faucet, hot tubs that aren’t drained after each use and large plumbing systems.