Infographic: What is Legionella

Legionella is a group of bacteria found in natural water sources, such as lakes, streams and groundwater. It can also be found in human-made water systems and devices.

Legionella can become a health concern when it grows in these systems and devices, and is inhaled in the form of droplets and mists released into the air.

Possible sources of Legionella

• hotubs
• humidifiers
• water heaters
• decorative fountains
• showerheads and sink taps
• home plumbing systems
• building plumbing systems
• cooling towers (cooling towers for buildings)

Conditions that support Legionella growth

• warm temperatures
• standing or still water
• settled particles and biofilm (a slimy, glue-like material containing microorganisms and nutrients)

Health effects of Legionella

Legionella can cause two types of illness in humans: Legionnaires' disease and Pontiac fever.

Legionnaires' disease is a serious respiratory illness that results in pneumonia, lasting weeks to months, and can lead to death.

Pontiac fever is a milder illness, causing flu-like symptoms. People with Pontiac fever generally recover in 2 to 5 days without treatment.

Who is at greatest risk

• people over 40 years of age
• current and former smokers
• people with chronic lung disease
• people with underlying illnesses and weakened immune systems

How to reduce your risk

• Maintain your water heater temperature at 60°C
  • To reduce the risk of scalding the temperature of the water at the tap should be no higher than 49°C. You should contact a qualified plumber to install mixing valves to control the tap water temperature.
• Regularly clean and disinfect mist-producing devices in your home (shower heads, humidifiers, hot tubs) according to manufacturer directions
• Run the hot and cold water taps for a few minutes after not using them for more than two weeks
• Periodically drain and flush your water heater, according to manufacturer directions, to reduce settled particles

Related links:

• Legionella
• Water quality and health