Contamination with the legionella bacteria occurs when contaminated water is turned into mist and the bacteria is inhaled. Drinking contaminated water is not dangerous. In shower rooms where the water is standing still for a longer period of time, or where the temperature does not exceed 60˚C, precautions must be taken to prevent legionella
As a supplier of water heaters, we are working to prevent legionella. Some of our appliances have a legionella prevention program integrated in the control. For other devices, we recommend using government guidelines to prevent legionella.
What should you pay attention to?
Ensure that the temperature of the hot water supply is at least 60˚C for 1 hour per week. The bacteria cannot live at temperatures above 60˚C. This is especially important with solar water heaters. These must be equipped with an after heater that keeps the water above 60˚C for at least 1 hour per week. If you have questions about the settings and installation of your water heater, please contact our Technical Support Group.
If an A.O. Smith device is equipped with an automatic legionella prevention option and it is activated, the water will be automatically heated to 65°C once a week. The water maintains this temperature for at least 1 hour to eliminate the legionella risk. The time is freely adjustable. By default, this is set to Monday from 2:00 AM to 3:00 AM.
What about the water in the pipes?
The above applies to our water heaters. Of course, the pipes in the hot water system are also important. If water has been standing there for a longer period of time, this can of course also entail risks. Advice for this has been drawn up by Isso and the government.
Isso publication 55.1 recommends the following methods to prevent legionella:
- Rinse for 20 minutes with water at 60°C or more
- OR: Rinse for 10 minutes with water at 65°C or more
- OR: Rinse for 5 minutes with water at 70°C or more
Do you want to know more about the occurrence of legionella or how to restart your hot water system?