How to Replace an Anode Rod (6 Steps)

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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.

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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.

You may also want to consider upgrading to a powered anode rod such the Corro-Protec model. It doesn’t sacrifice itself like a traditional anode so it’s maintenance free. If you currently experience smelly hot water, it’s a must.

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

anode-rod-replacementThe 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-rodAnode 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.

In my opinion, a powered anode rod is the best but the price can be considerably more than a traditional sacrificial anode.

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.

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Check out the video below to see how to replace the anode rod.

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Comments

  1. Seriously if you drain your water heater yearly your anode rod should last a good 10-15 years if not longer. I read reports people having an erode anode rod with soft water because of the salt ions sticking on there.

    Reply
  2. So I treated (shocked) my well for 16hrs. Drained all my my lines. Water was fine then. Little over a week my hot water heater started smelling. I Changed the rod. Two days later the hot water smells again. What is anyone’s opinion

    Reply
    • I have the same problem. Seems like its anaerobic bacteria that have taken up residence inside the hot water tank, fed by the magnesium anode and releasing hydrogen sulfide gas. I thought it was septic overflow in the well (stinky and black water) until I realized it was only the hot water. Cold water tap is fresh and clean.

      One suggestion is to crank the heating temp way up to try and cook them (every surface inside must be over 165° F, even far away from the elements, or they will reestablish a colony. I am trying max temp for a few hours, and then may try keeping it a little higher than usual in the long run. Guessing that my conservation efforts in turning down the temp to save energy has led to this bacterial overgrowth.

      I have had problems with iron-eating anaerobic bacteria clogging up the wellscreen, softener and filters before, so I am going to increase my efforts in treating the well more often too. Maybe chlorine and heat together will keep it under control.

      Reply
    • You need a Softners to take all the chemicals and other stuff react with the metal the anode rod is made of.
      Look up Edenwell Springs if you are in Texas they can help you with your problem. Then you never have to worry about changing the anode rod.

      Reply
  3. If I have limited clearance, can I cut the bottom 8″ of the new magnesium anode rod before inserting it. Will the shortened anode rod still protect the bottom of the tank. Please reply.

    Reply
    • Yes, you can cut it and it will still do what it’s supposed to. Keep in mind that with less material, it will “sacrifice” itself a bit quicker than if it were the normal length.

      Reply
  4. If you must cut some of the anode rod to have room to install it, is it ok to drop the cut off piece into the tank (gas style) or should I tie a string to it and lower it slowly into the tank to prevent damage to the glass lining?

    Reply
    • Definitely don’t drop it in the tank. You may damage the lining and it’ll likely make noises as it bumps against the insides when water is moving.

      Reply
    • Pull it up, put a vise grips on the bottom of the exposed part, cut it above the visegrips, then pull the rest of it up and out. Under no circumstances leave or drop half of the corroded mess back into the tank!

      Reply
  5. Can you put lime away or vinegar in a tank for a few hours or even a day to help loosen the deposits before scrubbing? Obviously a thorough rinse would be required but will the acid damage the tank?

    Reply
  6. my water heaters only last 4 years or so. is it because I have to have my water softened? the water here is very hard.

    Reply
    • With hard water, regular water heater maintenance is very important. Calcium and magnesium can build up within the tank and reduce its lifespan. I’d recommend flushing the tank twice each year as that will be a big help. Adding a water softener would be ideal though.

      Reply

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