Water heaters use an anode rod to attract and remove sediments from the water being heated. An anode rod will corrode and deteriorate over time until it’s no longer capable of functioning and has to be replaced. This is a common problem with older water heaters and in certain parts of the country.
This part literally sacrifices itself to keep the tank in optimal condition. That’s why it’s also referred to as a sacrificial anode. Without it, the water tank would start corroding from the inside out which would eventually result in a severe leak at the bottom.
These anode rod replacement instructions presented here are generalized to work with a wide selection of brands and heater designs, and you may have to modify some steps to match your particular model. For example, the anode rod on some GE models is concealed beneath a plastic cap that must removed before you can access the component.
Step 1 – Shut Off the Power and Water
Before performing any work on a water heater, you should always turn off the circuit breaker or turn off the thermostat on gas models. If your gas water heater has a “Vacation” setting, that will allow you to work on the unit without relighting the pilot afterward. If there is a valve on the cold water supply line, turn that off, otherwise turn off the water at the meter or pump.
Step 2 – Locate the Anode Rod
The anode rod will be located on the top side of the unit. In some cases, it may be directly connected to the hot water outlet line on top of the heater. If you have the user manual for the water heater, it will include a diagram which shows where the anode rod is located, otherwise consult the manufacturer’s website.
Step 3 – Drain the Tank
Connect a garden hose to the drain outlet near the bottom of the heater. Extend the hose to an outside location or a plumbing drain that is lower than the tank. Drain the tank only until the water level is beneath place where the anode rod is located. Water will not drain from the tank until the drain valve is open and a hot water valve is opened. You will get faster results by turning on the hot water faucet closest to the heater.
Tip: Might as well completely flush and clean the water heater at this time since have the work is done.
Step 4 – Remove the Anode Rod
The anode rod can be removed with a boxed end wrench or socket. If it will not turn using a wrench, use a socket and breaker bar. Tightening the anode rod slightly will help break the threads loose, making removal easier.
Never use penetrating fluids such as Liquid Wrench on water heater components, as these fluids could contaminate your hot water supply.
- It is a good idea to have a helper hold the tank while removing and installing the anode rod, as twisting the water heater could lead to leaks or broken pipes.
- In rare situations, you may have to cut a pipe in order to change the anode rod.
- If you have limited clearance, it may be necessary to bend the rod to get it out.
- Never bang on components of a water heater, as the tank liner is easily damaged.
- If the anode rod is corroded with sediment and is too large to lift out of the tank, it means that the component is still functioning. In this situation, reinstall the existing anode rod.
Step 5 – Install the New Anode Rod
If you have limited clearance, you may need to purchase a flexible anode rod. With the threads on the new anode rod pointed downward, wrap them with plumber’s tape or lightly cover them with joint compound.
Insert the new rod, or the old one if it is not being replaced. Turn the component clockwise until it cannot be turned by hand, then tighten it another 1/2 turn using your socket wrench. Do not allow the water heater to turn or twist while doing so.
Aluminum vs Magnesium Rods
Anode rods are made of either aluminum or magnesium. If you ask most professional plumbers, they’ll tell you a magnesium anode rod is preferred simply because it produces a stronger current than aluminum types. This in turn allows it to do a better job of fighting off tank corrosion.
The biggest drawback with magnesium is that in some instances, the material may react with bacteria in the water to produce a slight sulfur smell, something aluminum rods don’t have an issue with.
Step 6 – Restore Water and Power
Make sure the drain is closed, and turn the cold water supply on. Open the same hot water valve as you used to drain the tank and allow it to flow until all air has been removed from the tank. The faucet will make spitting or hissing sounds periodically as air escapes through the line.
- Check for leaks and make adjustments as necessary.
- Restore power or turn the gas thermostat to the desired water temperature.
Check out the video below to see how to replace the anode rod.