How to Repair a Leaking Water Heater

Leaks are a common problem for older models of water heaters in homes. Leaks are a sign of wear and age on the appliance. “You will want to inspect three areas of a water heater in order to determine the source of the leak, the extent of the repair and whether the part or the entire appliance need to be replaced,” according to Jim Campbell, owner of PDQ Cicero Appliance Repair

OBX has provided a list of the three water heater parts to inspect as well as troubleshooting tips on how to complete the necessary repairs. You can use our online contact form or consult a local appliance repair service we recommend. Please continue reading:


The first part to inspect on a leaky water heater is the drain valve. You will find the drain valve on the side of the appliance. The part is typically made of plastic and a leak will be easy to identify.

“The reason a drain valve might leak is the presence of sediment inside the water heater tank itself. Attempt to loosen and then tighten the drain valve and then see if the leak continues. If the leak does continue, you will need to replace the part,” says Campbell.

Before you replace the drain valve, turn off power to the appliance. You should also turn off the pilot light if you own a gas water heater. This is an important safety measure in order to complete the replacement of the part and repair of the leak. You should also turn off the cold water inlet valve and place a hose inside of the tank for draining. This will prevent leaks during the repair. You will then need to remove the old drain valve with a pipe wrench before installing the new part.

The new part should be fastened tightly and be facing downward. You can place plumber’s tape over the exterior of the fittings in order to further secure the seal and prevent against future leaks from the water heater.


You should inspect the drain valve first. If the leak isn’t there, we recommend looking over the pressure relief valve on the side of the appliance. This is the second most likely part to be responsible for a hot water heater leaking. This part performs a safety measure to prevent and release pressure buildup in the machine. The best course of action for this repair is to replace the pressure relief valve.

Be sure to disconnect power to the appliance and turn off the pilot light on gas models. Also drain the tank to a level below the relief valve. Please be careful as the water inside of the tank will be extremely hot. You should also turn off the cold water inlet valve during this step of the repair process. Then remove the relief valve with a pipe wrench. Be careful not to touch the valve with bare hands. It will be very hot!

Now tighten the new valve in place on the side of the hot water heater and fasten the valve with Teflon tape or plumber’s tape for a secure fit. Be sure that the valve faces downward after installation.


The last part to inspect on a leaking hot water heater is the heater element gasket. This part is only found on electric models. The part is enclosed behind the appliance under the covers on the side of the unit. You will need to remove the covers first before removing and replacing the element gasket.

Before removing the leaking heater element, turn off the hot water heater and drain the tank of water. Be careful for hot water temperatures. Also, shut off the cold water inlet valve so no other water fills inside of the tank during the repair. You can now unscrew the old element gasket with a socket wrench or an element wrench.

Now install the new gasket on the side of the appliance and fasten it tightly to the appliance. Then, connect the necessary wires to the element before replacing the cover panels on the back of the unit.