The sacrificial anode of a water heater

- What is it? When should you replace it? -

Beyond its serious name, the sacrificial anode is essential to the proper operation of your water heater. It is a long metal rod, made of magnesium or aluminum, which extends through the tank’s interior. It attracts particles of iron, limestone or other minerals present in the water through an electrochemical process and corrodes in place of the tank. In other words, it “sacrifices” itself to extend the life of the water heater.

Most water heater manufacturers will recommend inspecting the condition of the sacrificial anode every one (1) to three (3) years and replacing it when consumed more than 50%[1]. This is especially true if you have hard water or use a water softener.

Careful though! In some cases, replacing your water heater’s anode rod yourself could void the appliance’s warranty. Check the terms of your warranty or consult your supplier before undertaking this operation.

Where to find the anode for your water heater?

You can easily find replacement anode rods for standard water heater models in hardware stores or superstores. Usually, you will find those made of aluminum and their average price varies from $20 to $40. Make sure you note down your water heater model and tank size (in gallons) before buying the anode rod.

A special order will probably be required for compact water heaters or those that exceed 60 gallons.

How to inspect the sacrificial anode?

Since the sacrificial anode is immersed in the tank, you will have to drain the water heater to check its condition. You may only have to drain it partially or empty the water heater completely, depending on the model. Make sure you know the draining process before you begin. Then, follow these steps:

1- Before anything else, turn off the power to your water heater.

2- Consult the manufacturer’s Manual to locate the anode rod depending on your water heater model. Most are accessible from the top of the appliance, hidden under a plastic cap. You may have to remove insulating material to reach.

3- Now proceed with draining the tank, at least partially.

4- Remove the corroded anode rod with a 1 1/16-inch socket wrench. Wearing work gloves is recommended for this step since the rod can be hot. You should expect some resistance at first before the worn-out anode gets freed.

5- Install the new anode and restart your water heater by completing the draining process.


Should you have any more questions or concerns regarding the replacement of your sacrificial anode, please do not hesitate to contact us. We are here to help!

[1]GIANT Inc., Residential Water Heater: Owner’s Manuel – Installation and Operating Instructions (p.10)