The important role of water heater anodes

It is an obvious fact of nature. If metal sits in water, it's bound to rust and finally oxidize down to nothing. This may spell the end for water heaters in conjunction with their steel interiors, however that is not the case thanks to the existence of anode rods. These simple devices literally expose themselves to the bullet for the survival of the water heater. This article explains how these anodes work and how householders can inspect them early and regularly for possible replacement.

Conditions that exacerbate rusting and corrosion inside water heaters include:

Water acidity

Water contains gases that naturally liquefy, such as carbon monoxide, increasing the acidity levels of water.

Chemical processes

Any contact between steel and oxygen or vapour, simply kick starts the process of corrosion.


Generally, water heaters operate at extremely high temperatures, and heat intensifies the process of rusting.

The use of a variety of materials

Water heater manufacturers use a wide range of materials in designing components forming the water heater. Consequently, these materials generate electrical conductivity which also enhances corrosion.

How water heater anodes work

Water heater anodes are long tubes of magnesium or aluminium connected to a steel wire core. Generally, magnesium and aluminium anodes are more reactive compared to steel, and that's why they are used in the steel interior of a water heater tank.

With the presence of a magnesium or aluminium anode, all the above-mentioned rusting challenges inherent to water heater operations are countered. You see, the magnesium anode rod will succumb to rust before the steel interior of the tank and other components do. Afterwards, it provides electrons inside the tank, producing a setting that stops decomposition of the tank as well as its elements. Water heater anode rods are referred to as sacrificial lambs because they sacrifice themselves to rust in order to safeguard the water heater.

Check your anode rods

Householders can check the condition of magnesium anode rods for possible corrosion damage without the help of a plumber. You only need a ratchet wrench to remove the rods from the top section of the water heater tank where they are normally located. If at least six inches or more of the steel core wire is damaged by corrosion, then you need to replace your sacrificial anode rods. This serves as the tell-tale sign of an anode that needs replacement. A professional plumber should always be called upon to replace the anode rod.