The REAL Ideal Temperture Setting For Your Water HeaterAuthor: Pacific Northwest Inspections Group, LLC Date: 13-Apr-2017. Category: Plumbing Add to Favorites
We all hear that 120 is the recommended setting from local and State departments, but is it?
What happens at 120 degrees?
There are two main and opposing risks:
At 120 degrees bacteria can survive but does not multiply. It takes 8min for a 1st degree burn. Dust mites are not killed at this temperature.
According to the paper Legionella and the prevention of legionellosis, found at the World Health Organization website, temperature affects the survival of Legionella as follows:
Above 70 °C (158 °F): Legionella dies almost instantly
At 60 °C (140 °F): 90% die in 2 minutes
At 50 °C (122 °F): 90% die in 80–124 minutes, depending on strain
At 48 to 50 °C (118 to 122 °F): Can survive but do not multiply
32 to 42 °C (90 to 108 °F): Ideal growth range
It also takes 131 degrees to kill Dust Mites.