Temperature and the Risk of Legionella

Ice cream, beer gardens and sunscreen are usually the first things that come to mind when summer hits us but don't forget to think about the increased Legionella danger from your water systems. A known contributing factor to the rise in legionnaires' disease cases is the lengthier, warmer, and wetter summers. 

 

 

Legionella bacteria flourish between 20 and 45 degrees Celsius, go dormant below 20 degrees Celsius, and quickly perish around 60 degrees Celsius. The main strategy for preventing legionella growth in our water systems is the temperature (although other methods using chemicals are also widely used). Any cold water that is held (in tanks or pipes) is more likely to warm up above 20 C in warmer weather or in situations where water use is lower than usual. Bacteria may begin to proliferate exponentially where this occurs. 

 

The "causal chain" refers to the key causes of increased Legionella risk in any water system. 

 

• CONTAMINATION - Bacteria are present in incoming water and thrive in artificial water systems due to the favourable conditions for growth. 

 

• AMPLIFICATION - Bacteria multiply to high levels. 

 

• AEROSOLISATION - The release of bacteria in an aerosol (e.g. fine spray from taps, showers or hoses) 

 

• EXPOSURE - The person is then exposed to the bacteria and breathes it into their lungs.