The water temperature in the water heater in your house can be adjusted using a device called the aquastat. However, before you start making any adjustments to try to find the ideal temperature—either to save energy or for comfort—we must caution you about what can happen if the water heater is set too low or too high:
- Too low: Both we and the EPA recommend you never set the aquastat lower than 120°F. The water must be hot enough to kill off bacteria and other disease-causing microbes that may develop in the tank.
- Too high: You create a risk of scalding temperatures in the house. We don’t recommend a setting any higher than 140°F.