It’s easy to forget about your water heater—until you step into a freezing shower or get scalded washing your hands. But the temperature setting on your water heater affects more than just your comfort. It can also impact your energy bill, your safety, and even your health. So what’s the magic number?
Let’s break it down.
The Goldilocks Zone: 120°F
Most experts agree that 120 degrees Fahrenheit is the sweet spot for your water heater setting. It’s warm enough to meet everyday needs like showering, laundry, and dishwashing, but not so hot that it wastes energy or poses a scalding risk.
Here’s why 120°F is considered ideal:
Energy Efficiency: Lowering the temp from 140°F to 120°F can reduce your water heating costs by 6–10%, according to the U.S. Department of Energy.
Safety: At 120°F, water is hot enough for comfort but much less likely to cause burns—especially important for households with children or older adults.
Health: It’s still warm enough to prevent most bacteria from thriving in your tank, including Legionella, which can cause Legionnaires’ disease.
What If You Need to Set It Higher?
In some cases, you might need to raise your water heater temperature to 130–140°F:
If someone in the home has a compromised immune system
If your dishwasher doesn’t pre-heat water
If your water heater is older and tends to run cooler than its setting
But if you go above 120°F, be sure to install anti-scald devices at faucets or showerheads—or talk to a plumber about temperature-regulating valves.
Don’t Just Set It and Forget It
It’s a good idea to check your water heater temperature once or twice a year. Some units have an external dial with easy markings. Others may require removing a panel and adjusting a thermostat with a screwdriver. (Always turn off the power or gas before making adjustments.)
You can also test the temperature at the tap with a kitchen thermometer. Run hot water for a few minutes, fill a cup, and measure. If it’s more than 120°F, turn it down slightly and retest in a few hours.
Bottom Line
120°F is ideal for most homes—it’s safe, energy-conscious, and effective. But depending on your household’s needs and your water heater’s performance, you might need to adjust slightly. A few degrees can make a big difference in both comfort and cost.
If you’re unsure about how to safely change the setting—or if your hot water isn’t consistent even after adjustments—it may be time to call in a professional.
