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Replacing an anode rod in a hot water heater tank

Anode Rod

Originally contributed by Jeff Butler • last updated 1/21/2021

For the most part, hot water heaters require very little maintenance. However, the sacrificial anode (aka, the anode rod) is one part that will probably need to be replaced every few years.

Definition

The term anode rod (or sacrificial anode) typically refers to a replaceable metal rod (aluminum, magnesium, or zinc) that screws inside most hot water tanks. Through an electrochemical process, anode rods are designed to attract the corrosive elements in the water, protecting the steel metal walls inside the hot water tank from oxidation and deterioration. In other words, the aluminum or magnesium is sacrificed to the corrosive elements, saving the metal water tank from eroding. Powered anode rods are non-sacrificing anode rods that produce an electric pulse to prevent corrosive elements from causing deterioration.

How To Tell If An Anode Rod Is Bad

Unlike powered anode rods, traditional sacrificial anodes are designed to self-destruct. As a result, you’ll need to stay on top of regular maintenance and watch out for signs of deterioration:

  • Be on the lookout for rusty colored water and/or water that smells bad like rotten eggs. Discolored water and a sulfur smell could be a sign of oxidation and deterioration in your tank as the result of a bad anode rod.
  • In general, your anode rod should be replaced every three to five years. It’s a good idea to check your hot water heater’s manual or contact the manufacturer for a regular maintenance schedule.
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