The recommended water heater temperature is 120 degrees Fahrenheit which balances comfort safety and energy savings. This setting prevents scalding reduces energy consumption by up to 10 percent and slows mineral buildup. Households with immunocompromised members may set to 140 degrees for added sanitation. Check temperature at the faucet using a thermometer after adjusting. Gas heaters have a dial on the gas valve while electric models require adjusting thermostats behind access panels.