Getting the proper hot water temperature setting on your water heater can be tricky.
The CDC recommends setting the temperature of your water heater to 120 degrees Fahrenheit. This is a setting that will prevent the build up of Legionella that can cause Legionnaire’s disease.
At the same time you should not go hotter than 120 degrees to prevent scalding. The following shows the time in seconds for hot water at different temperatures (in Fahrenheit) to scald an adult and a child with third degree burns:
160 degrees – 1 second (adult), immediate (child)
150 degrees – 2 seconds (adult), 0.5 second (child)
140 degrees – 5 seconds (adult), 1 second (child)
135 degrees – 10 seconds (adult), 4 seconds (child)
130 degrees – 35 seconds (adult), 10 seconds (child)
125 degrees – 1.5 to 2 minutes
120 degrees – 5-10 minutes
It is recommended to follow the manufacturer’s instructions on setting the temperature of the water heater. If you are unsure how to safely set the temperature then consult with a qualified professional like a plumber.