How to Replace the Anode Rod in a Hot Water Heater – Eliminate Rotten Egg Odor

Does your hot water smell like rotten eggs? When was the last time you replaced the anode rod in your hot water heater? Follow the step by step instructions in this picture guide to learn how!

How to Replace the Anode Rode

The anode rod, or sacrificial rod, is a metal component inside your hot water heater whose purpose is to corrode before the walls of your hot water heater do, hence the name “sacrificial” rod. It is recommended that you replace this rod once it has corroded away. Since you don’t know until you’ve removed it, it is usually recommended to replace the rod every 5 years.

These rods are typically made out of magnesium or aluminum, however, if you have sulfur in your water, the magnesium or aluminum may interact with the sulfur creating hydrogen sulfide gas, which stinks, like rotten eggs. Although your hot water still is safe to drink, you may want to replace your anode rode with an aluminum-zinc rod. The zinc will help to neutralize the hydrogen sulfide gas production, eliminating the horrible smell!

Alright, let’s get started.

Assemble the Parts and Tools

First, decide which rod you need. To recap:

If your hot water smells fine – Replace with a Magnesium Rod

If your hot water smells like sulfur – Replace with an Aluminum-Zinc Rod

For more information on the various rods, these are Amazon links to the corresponding parts.

Link to Magnesium Rod (Water already smells fine)

Link to Aluminum-Zinc Rod (Hot water Stinks)

These rods are like 44″ long, so if you don’t have a lot of head-room over your hot water heater, get a flexible rod:

Link to Flexible Aluminum-Zinc Rod

Tools required:

Step-By-Step Instructions

The first step is to turn off the electricity or gas to the hot water heater.

Then, turn off the water supply to the hot water heater. In the example shown here, the red handle should be turned to the horizontal position to turn off the water to the tank.

Next, go to the nearest faucet and turn on the hot water for 20-30 seconds. This will relieve some of the pressure in the tank.

Now, open the drain valve at the bottom of the tank and drain out several gallons of water. Attach a hose and run it to a nearby drain or drain it into a bucket.

Careful, the water will be hot!

Next, remove the old anode rod. To do this, go to the top of the hot water heater and find the hex head of the rod. It might be under a cap. It may also have some foam spray-type insulation around it, if so, pick that away.

Once you’ve located the hex head, put the socket on and unscrew it. It will be very tight. An impact wrench is the suggested method. If you go with the ratchet, you will likely need a breaker bar and a helper to hold the water tank still while you reef on the socket.

Here’s an image showing the rod removal using this impact wrench.

Once the rod has been loosened by the impact wrench, unscrew the rest of it by hand until you can pull it out. Here is an image of the old and new rod side by side.

Here is a closer view showing the corrosion on the existing rod.

Next, put some teflon tape on the threads of the new rod to create a better seal. Put the new rod into the tank and get the threads started by hand. Don’t use the impact wrench to tighten the new rod in place. Use a socket wrench and just make it tight enough so that it does not leak. Don’t go overboard and damage the tank.

Once the new rod is in place and tightened up, turn on the water supply to the tank so that it fills up again.

You will need to ‘burp’ the tank. To do this, locate the small relief valve on the top of the unit and flip it up to let the air seep out. If water starts to come out, shut the relief valve.

You’re all set! Turn the power back on to the unit.

I hope this helps. While you are at it, you may want to flush your hot water heater at the same time since it involves a lot of the same steps and is relatively easy. It will remove sediments from your tank. See this post on flushing your hot water heater.

Here is the list of parts and tools needed for this job.

Anode Rods: