What Is a Water Heater Anode Rod?

An anode rod is the most important element inside a water heater tank. This metal rod runs through the length of the tank. Anode rods are steel wires encased in metal made of either magnesium, aluminum or a zinc/aluminum alloy. The material composition of the water anode rod can significantly impact the performance and longevity of your water heater as well as the minerals inside of your home’s water supply.

 Magnesium Anode Rod

A magnesium anode rod is a good choice for households with soft water. But if you have hard water running through plumbing pipes, stay away from magnesium anode rods. This metal doesn’t hold up to hard water minerals such as elevated levels of magnesium and calcium. Hard water will corrode magnesium anode rods quickly. This can lead to rust, corrosion and a water tank in desperate need of replacement if not found in time.

 What Does a Water Heater Anode Rod Do?

A water heater anode rod prolongs the life of tank water heaters by a process known as electrolysis. Electrolysis prevents water heaters from degradation. The anode rod attracts and absorbs harmful particles, such as sediment buildup, to its surface. Without an anode rod, corrosion, rust, hard water sediments and heat adhere to the rod rather than the tank lining that can cause severe damage.

 If you were to examine the inside of a water heater tank, you’d likely discover the following conditions that can compromise your water heater. 

Chemical reactions between minerals in a tank can cause rust and corrosion.

Improper pH balance: A healthy pH balance of water should measure around 7.0. When the water becomes too acidic and lacks alkaline, corrosion occurs

Excessive heat: Heat speeds up the processes of corrosion and rust degrading the tank

These harmful conditions make water heaters vulnerable and affect their performance and longevity. However, the anode rod, sometimes called a “sacrificial lamb”, acts as a shield that sacrifices itself (in a sense) for your water heater. Rather than these corrosive elements accumulating on the lining of the water heater, the elements collect on the anode rod. This can save you the expense of buying a new top-performing water heater.

How Often Should You Check and Replace the Anode Rod?

Water heater anode rods require routine inspection and replacement. You should have them inspected annually, whether you check the anode rod yourself or call in an experienced plumber to do the inspection. Most anode rods need replacing around every two or three years. The exception is a power anode rod that can sometimes last the entire lifetime of a water heater. But the frequency of replacement can also depend on the following factors. 

• A home’s water quality.

• The type of anode rod installed in a water heater.

• Whether or not the house has a water softener.

• How much water is used in the household.

• The pH levels.

• Proper water heater maintenance.