Water Heater: Why is my water heater making the water too hot?

First, adjust the thermostat setting to lower the water temperature if the water heater thermostat is set above 130 degrees. The 120-degree setting is standard. If 120-degree water is too hot for you to use, try setting the thermostat at 110 degrees. Next, check the thermostats. The upper and lower thermostats in an electric water heater must fit snug against the tank to properly transfer heat in order for thermostats to detect the water temperature correctly. To check the thermostats, turn off the power to the water heater and remove the thermostat access covers. Check the thermostats' positions and adjust the thermostat brackets if necessary to press the thermostats against the side of the tank.

A thermostat that's stuck in the 'on' position will cause the heating element to stay on constantly, overheating the water in the tank. Or, if the element breaks, it can make contact with metal inside the water heater, creating a short-circuit. In that case, electric current flows through the element to the metal, causing the element to heat constantly. Examine the elements and replace an element if damaged.

Follow the steps in our troubleshooting video to figure out why an electric water heater overheats. Replace a thermostat if it's not regulating water temperature accurately.

In a gas water heater, a broken thermostat won't shut off the burner when the tank water reaches the set temperature. Replace the thermostat if it doesn't cycle the burner on and off to keep the tank water at the set temperature.