Replacing a Water Heater Heating Element

Testing the Heating Element

Electric water heaters typically have two heating elements — upper and lower — each controlled by its own thermostat. Before testing, turn off the circuit breaker and use a non-contact voltage tester to confirm power is off. Remove the access panel, insulation, and plastic cover to expose the thermostat and element terminals. Set a multimeter to the resistance (ohms) setting and touch the probes to the two element terminals. A working element shows 10 to 16 ohms of resistance; an infinite reading (OL) means the element is burned out.

Draining for Replacement

With the power off, close the cold water inlet valve and connect a garden hose to the drain valve. Open a hot water faucet in the house and open the drain valve. For the lower element, you only need to drain below the element level — about halfway. For the upper element, drain to just below that element's level. If the drain valve clogs with sediment, try connecting a wet/dry vacuum to the hose end to create suction.

Removing and Installing the Element

Elements are either screw-in type (with a large hex head) or flange type (with four bolts). For screw-in elements, use an element wrench (available at hardware stores) to turn it counterclockwise. Clean the threads and O-ring groove in the tank opening. Install the new element with a new rubber gasket, tightening firmly but not excessively. For flange types, remove the four bolts, replace the gasket, and bolt the new element in place with a criss-cross tightening pattern.

Refilling and Restoring Power

Close the drain valve and remove the hose. Open the cold water inlet valve and wait for the tank to fill — the hot water faucet will sputter and then run a full stream when the tank is full. Close the faucet. Inspect the new element area for leaks. Only after confirming the tank is completely full, restore power at the circuit breaker. Turning on power before the tank is full will immediately burn out the new element, as they are designed to operate submerged in water. Wait 30 to 60 minutes for the water to heat, then test at a faucet.