Legionella is a gram-negative aerobic bacterium of which more than fifty species have been identified: the most dangerous is the "legionella pneumophila".

Approximately 90% of "legionellosis" cases are attributable to this type of legionella.

It is an infection that mostly affects the respiratory system and can manifest itself in the form of headache, high fever, muscle pain, chest pain, disorientation and confusion.


Water temperatures


25°C -50°C : development 
35°C -45°C : critical range of development and proliferation
>55°: beginning of the progressive death of the bacterium
70°C -80°C :rapid death rate of legionella




These are the main conditions that favor the spread of the Legionella bacteria:
water stagnation;
• presence of scale and sediment;
biofilm [micro-organism aggregation];
• presence of amoebae [single-celled organisms].
inadequate water circulation temperatures in the system


 • limit unforeseen overheating (eg through insulation of pipes, correct positioning of hot and cold water pipes ...)
• organize the production and storage of hot water at temperatures above 65 ° C;
• guarantee an adequate recirculation line to support hot water and let it flow before using it;
• provide for the maintenance and cleaning of taps, shower diffusers and water storage tanks
• avoid sources of emission of water vaporized outside homes