What Temperature Should You Set Your Water Heater?
Most water heaters ship set to 140°F, but the U.S. Department of Energy recommends 120°F for the right balance of safety, energy savings, and bacteria control. Here is how to choose and change it.
The Recommended Setting: 120°F
120°F is hot enough for showers, dishes, and laundry, while reducing the risk of scalding (especially for kids and older adults) and cutting standby energy loss. Every 10°F lower saves roughly 3-5% on water heating costs.
When to Go a Bit Higher
If someone in the home is immunocompromised, or you have a dishwasher without its own booster heater, 130-140°F may be warranted to ensure sanitizing and limit Legionella bacteria. The trade-off is scald risk and higher bills.
How to Change It
On a gas heater, turn the dial on the thermostat/gas valve at the bottom. On an electric heater, turn off the breaker, remove the access panel(s), peel back insulation, and adjust the thermostat dial(s) with a flathead — set both upper and lower to the same temperature. Wait a few hours and check the temperature at a tap with a thermometer.
Parts & Tools
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FAQ
140°F delivers hotter water but raises scald risk (a serious burn in seconds) and energy bills. 120°F is the recommended balance for most homes.
Yes. Dropping from 140°F to 120°F can cut water-heating energy use noticeably, often 6-10%, with no real loss of comfort.
Always unplug an appliance and shut off its water supply before servicing. This guide is informational and not a substitute for a qualified technician.