How to Carry out a Water Heater Anode Rod Replacement

Updated
Categories Water Heating
Replace your water heater anode rod in 9 simple steps.

Did you know that the anode rod in your hot water heater should be replaced every three to five years? Many of us assume that the hot water heater is supposed to do its job, forever, with no interference from us.

When you hear talk about replacing the anode rod, chances are, you’ll be scratching your head wondering what an anode rod is. More importantly, how do you replace it?.

Here we’ll share in detail how a water heater anode rod replacement is done and why. Let’s dive in.


What Is an Anode Rod?

Also known as a sacrificial rod, the anode rod is made from a steel wire that is covered with magnesium, aluminum or aluminum/zinc alloy. There are two types of anode nodes — the nipple type and the plug type.

The nipple type rod is located on the hot water outlet while the plug type can be found on top of the tank. The plug type anode rod will have a separate opening and depending on the heater model, it may be concealed under a plastic cap.

The role of the anode rod is to protect the steel tank from rusting. Steel is a more noble metal (more resistant to oxidation and corrosion) compared to magnesium, aluminum, and aluminum/zinc alloys.

Since corrosive elements in water will always attack metals, the more reactive metals will corrode first. This leaves the steel tank intact. It’s the reason anode rods are called sacrificial nodes — they put themselves on the line for your steel tank (1).

Without the anode rod, your water tank will start to corrode from the inside, causing leaks. If this happens you’ll most likely have to buy a new tank.

An ‘eaten up’ anode that’s not replaced may end up breaking off and falling to the bottom of the tank. As water passes through it, it will bounce around and possibly destroy the water heater’s lining.

The damage done by the broken rod will shorten your heater’s life and you’ll need to replace it. Clearly, having a functional anode rod is important.

Signs That Your Anode Rod Needs Changing

One of the best ways to determine if the anode rod needs to be replaced is by taking it out and inspecting it. We’ll give you a breakdown of how to remove it in the next section.

If the rod shows signs of wear and is slightly corroded, you can put it back. If the steel wire is visible or it’s the only thing left on your anode rod, you should change it immediately.

In the case of the latter, it’s likely that water is now attacking your steel tank, and it may be too late to save it.

Other signs to look out for include:

  • Rust-colored water is drawn from hot water faucets only.
  • Pinging sounds coming from inside the tank. These may indicate a broken rod rattling around.
  • Faucet aerators clog frequently.
  • Foul smelling water.
  • Presence of a slimy gel around the faucet aerator.
  • Presence of foam floating in your heater. Aluminum rods are susceptible to this since aluminum produces a foamy waste by-product following corrosion (2).
  • Metallic taste in the water.

People living in areas with hard water may need to use a water softener, however, the composition of the water softener corrodes anode rods faster. If you use water softeners, you’ll need to replace your sacrificial rod more often.

How to Replace Your Anode Rod

Water heater anode rod replacement isn’t as hard as it sounds. In fact, you can do it yourself.

The step-by-step guide below is the general way to replace an anode rod, but some steps may differ depending on your model. If so, please refer to your owner’s manual or visit the manufacturer’s website for specific instructions.

You’ll need the following:

  • A new anode rod.
  • A 1-1/16” socket wrench. A closed-end wrench can work too.
  • Breaker bar or cheater pipe (optional).
  • Garden hose.
  • Water collection bucket (optional).
  • Teflon tape.
  • Flat blade screwdriver (optional).

Step 1.

Start by turning off the power supply. If you’re using an electric heater, you’ll need to turn off the circuit breaker. If you leave it on, air may come into contact with the heater’s heating element and burn it out.

With a gas heater, look for the vacation setting and turn the gas control valve to it. You can also turn the control valve to the lowest setting on the heater. Turning it off completely means you’ll have to light the pilot afresh.

Step 2.

Next, look for the anode rod. If you have the owner’s manual handy, you can find it from there. On most models, it’s located on top of the heater and may look like a hexagonal plug nut head. It may also be concealed under a plastic cap.

On some heaters, the sacrificial rod may be connected to the hot water outlet port. For the purposes of this article, we’ll be looking at anode rods located on top of the heater or on the side.

Step 3.

Close the cold water supply, or the main inlet supply. Then, open the hot water faucet closest to you. This helps release pressure from the tank by allowing air inside, breaking the vacuum so you and do the next step.

Step 4.

Connect the garden hose to the drain outlet at the bottom of the heater and extend the hose to a plumbing drain or outside your house. For the water to drain out of the heater, the hose must be lower than the level of water inside the heater.

The water that comes out of the heater is very hot and may exceed 125 degrees Fahrenheit. Ensure that no one is in contact with the hosepipe or exposed to the water as it’s being drained.

Heaters with anode rods located at the top should be drained until the level of water is beneath the rod. Those with anode rods on the side will require draining until the water level is lower than the anode rod port.

Once you’re done, shut the drain valve and remove the hose.

Quick Tip

Use the bucket to collect the water which can be recycled or used to water your plants when cool.

Step 5.

If the anode rod is concealed by a plastic cap, use a flat blade screwdriver to remove the cap and expose the anode head. Now use a wrench to carefully remove the anode.

Anode rods that have been kept in the heater for several years may be harder to remove. Have someone hold the heater in place as you try to extract it. This will keep you from damaging any pipe connections which will cause leaks.

Use a breaker bar to provide the leverage needed to break the seal.

A couple of tips here:

  • Avoid banging on the anode as you may end up damaging the lining of the heater.
  • If you’re having trouble removing the anode, even with the breaker bar, enlist the help of a professional plumber.
  • Contrary to some information you’ll find online, avoid using chemicals to loosen the threads on a snugly fit anode. These chemicals can get into the water heater and contaminate the water.

Step 6.

With the anode rod loose, lift it out of the heater. Be careful as it may be hot. An anode rod that shows signs of wear has been doing its job.

Depending on the location of the heater, you may not have enough space to pull out the anode. In this case, you can bend it to remove it. In rare cases, you may need to cut it.

Step 7.

Prepare the threads of the replacement anode with Teflon tape and be sure to wrap five or six turns. Insert the new anode and use the wrench to tighten it. Depending on your tank’s location, you may need to use a flexible anode bar.

Step 8.

Open the cold water supply and refill the tank. When water starts coming out of the hot water faucet we opened in step 3, your water tank is full. The faucet will most likely spit out air with the water initially.

Allow the water to run until all the air has been expelled. You’ll know your tank is free of air if the water is flowing freely, without any spitting.

Step 9.

Inspect the heater’s connections and around the new anode rod for leaks. If there are none, it’s time to turn on the power for an electric heater. Set the control valve back to its original setting on a gas heater.

Congratulations, you have successfully replaced your anode rod.


Done and Not Rusted

An anode rod plays a key role in your hot water heating system. It’s the distinction between a well-performing heater and one that’s rusty and in need of replacement.

You can choose to carry out the water heater anode rod replacement process by yourself or call in the professionals. Either way, it’s important for you to replace it before it wears out completely.

If you have any questions or comments, we’d love to hear them. Drop us a line in the comments section below and remember to click the share button.

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About the Author

Peter Gray

Peter has been a homeowner for 35+ years and has always done his own repair and improvement tasks. As a retired plumber, Peter now spends his time teaching others how they can fix leaks, replace faucets, and make home improvements on a budget.
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