Safety & Security
For Your Home
 
Water Heater Temperature Safety

Time/Temperature Relationships in Scalds
Reducing Hot Water Temperature
Temperature Guidelines

Safety and energy conservation are key factors to be considered when selecting the water temperature setting of the water heater’s thermostat. The lower the temperature, the greater the safety and savings in energy cost. To achieve this, we recommend a temperature setting of 120°F or less. Water temperatures over 125°F can cause severe burns instantly or death from scalds.

Note: Households with small children or invalids may require a 120°F or lower temperature setting to prevent accidental contact with HOT water.

TIME/TEMPERATURE RELATIONSHIPS IN SCALDS*

Temperature Time to Produce Serious Burns
120°F More than 5 minutes
125°F 1- 1/2 to 2 Minutes
130°F About 30 Seconds
135°F About 10 Seconds
140°F Less than 5 Seconds
145°F Less than 3 Seconds
150°F About 1-1/2 Seconds
155°F About 1 Second
160°F+ Instantaneously

*Table Courtesy of Shiners Burn Institute

Reducing Hot Water Temperature
Reducing the temperature safely saves energy by:
  • Reducing the amount of heat that is lost out of the hot water tank (known as stand-by losses). If appliances, such as clothes washers and dishwashers, use hot water at the temperature supplied by the water heater; and do not mix this water with cold water to achieve a set hot water temperature, additional savings will occur.
  • Avoiding possible burns or scalding. Water temperatures over 110°F - 120°F can cause severe burns in a matter of seconds.

Temperature Guidelines
Check the temperature setting of the hot water by placing a thermometer under a running faucet near the tank (thermostat settings on water heaters are not always accurate). The following are guidelines for common activities using hot water.
  • Hand Washing: 110°F - 115°F
  • Showers: 110°F - 115°F
  • Dishwasher rinse: 130°F – 140°F
  • Some models have build-in booster heaters that allow the water heater to be set at 110°F - 115°F.
  • New liquid soaps for automatic dishwashers are designed to work well at lower temperatures.
  • Experiment with the water temperature at the dishwasher and choose the most economical setting.
  • Laundry: 110°F - 120°F
  • With today’s detergents, most clothes can be effectively cleaned in either warm or cold water. Washing clothes in warm or cold-water will not only save energy, but will also prevent premature wear and fading of fabrics.

Adjusting the hot water temperature is relatively easy. (New water heaters, by law, are set at the safer lower temperatures.) A homeowner can usually make this adjustment. If they choose not to, they could have a plumbing or HVAC (Heating, Ventilating and Air Conditioning) contractor lower the temperature.
  • Electric Water Heaters: The thermostat is usually located behind a cover plate; and can be accessed by removing a few screws.
  • Many electric water heaters have two thermostats – one for the upper heating element and one for the lower. Make sure to adjust both of them.
  • When lowering the setting on an electric water heater, be sure to shut off the power at the circuit breaker/fuse box to avoid the danger of electric shock.
  • Gas Water Heaters: If the thermostat dial is visible, simply adjust it to the desired temperature.
  • The lowest temperature is the safest setting.
  • Experiment with the setting to find a temperature that provides adequate hot water, while still minimizing wasted energy.
 
   
 
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