Checking Your Water Heater's Temperature Setting

Finding a Sensible Setting

Many safety and energy organizations suggest about 120°F as a starting point for most households. Water at that temperature is comfortable for bathing and dishwashing and is far less likely to cause a serious burn than water at 140°F or higher, which can scald skin very quickly.

Some households have reasons to adjust. Homes with young children or older adults benefit from staying at or near 120°F. A home with a large family or an older dishwasher without a booster heater may want a little more. If anyone in the home has a weakened immune system, ask a health professional about the right balance.

How to Check the Actual Water Temperature

Dial markings are often vague, labeled with words like Warm, Hot or letters, so measure the water itself:

• Pick the faucet closest to the water heater and make sure no one has used hot water for an hour or so.
• Run the hot water for a minute or two until the temperature stops rising.
• Fill a cup and hold a cooking or candy thermometer in it.
• Compare the reading with your target. If you adjust the setting, wait several hours and test again before making another change.

Adjusting a Gas or Electric Tank

Make small changes. Thermostats are not precise, and it can take a full heating cycle for the tank to settle at the new setting.

Gas water heaters

The control knob is on the gas valve near the bottom of the tank. Turn it in small steps toward a lower or higher mark. Do not remove the control or touch the gas line.

Electric water heaters

Thermostats sit behind metal access panels, often one upper and one lower. Electrical terminals are exposed behind those panels, so you must switch off the breaker first. Remove the panel, fold back the insulation, and turn the adjustment screw with a flat screwdriver. Set both thermostats to the same temperature, then replace the insulation and covers before restoring power.

Energy Use and Comfort

A water heater loses heat through its walls all day, and the hotter the tank, the faster it loses heat. Lowering an overly high setting trims that standby loss. If you leave home for several days, the Vacation setting on many gas models holds the tank at a low temperature without turning the heater fully off.

Signs the Problem Is Not the Setting

If the temperature swings widely, the water is scalding even at a low setting, or you get only lukewarm water no matter what you do, the thermostat, a heating element, the gas control or a dip tube may be failing. Water that becomes extremely hot can also cause the relief valve to open, which is covered in our guide to testing the T&P valve. For these issues, schedule a water heater diagnosis instead of turning the dial higher.