Water heater anode rod is not a subject we talk about everyday. However, this small part is making sure we will have some hot water in years to come. Did you know that in North America, the average life span of residential water heaters is 8 to 12 years? Yet, these reservoirs have the potential to last much longer.

More than 8,000,000 water heaters are sent to the dump every year, which is an enormous amount; and we have the power to change that! Have you ever heard anyone say their heaters lasted 20 or more years? Well, it could be your case after reading this article!

What is Cathodic Protection and why water heater anode rod is important? 

To begin with, one should know that every steel water heater is equipped with a galvanic anode (also called sacrificial anode) to protect it from corrosion. Even if almost all water heater tanks are glass-lined, they still need something to protect it against corrosion since there is almost always some defects caused during transportation, installation or even manufacturing. The rust will then attack these defects much more severely and the life of the tank will be less than if it had not had glass-lined reservoir.

This principle, also known as Cathodic Protection, has existed for several years, and is used to protect several types of structures, such as submarines, boats or pipelines. There exists two forms of cathodic protection; galvanic protection and impressed current protection.

Sacrificial Anode 

Often overlooked, the sacrificial anode is the first component that should be maintained, and if needed, replaced, in order to extend the life span of our water heaters. However, replacing your anode rod requires a good sense of discipline as well as frequent monitoring. As the name suggests, the purpose of the sacrificial anode is to protect the water heater against corrosion by “sacrificing” itself. 

Its operation is rather simple: when two metals are found within a liquid, the one with the most negative electrochemical potential will corrode first. In order to protect your steel water heater (-0.6V), manufacturers use magnesium anode rod (-2.3V), aluminum anode rod (-1.66V), zinc anode rod (-1.1V) or a combination of aluminium zinc anode.

Since it constantly releases ions into the water, the sacrificial anode degrades over time, which limits its overall lifespan. As it degrades, the benefits and protection it provides decreases, which leads the steel tank to rust. 

Inspection Of The Water Heater Anode Rod

Most water tank manufacturers will recommend that you inspect the condition of the anode once every 1 to 3 years, and to replace the part if you notice wear and tear beyond 50% of its initial state. If you are comfortable with doing this task yourself, it should only take but a couple of minutes, however, we would recommend hiring a professional. We also recommend to drain the water heater once a year to limit sediment accumulation in the tank.

Sulfur Smell In Hot Water

The anode is also the main cause of rotten egg-like smell in hot water. Although many people would recommend removing it completely from the tank in order to correct the issue, we strongly advise against using this method. By removing the sacrificial anode from your tank, you deprive it of the only protection against corrosion it has. To find an effective solution against sulfur odors, visit: Sulfur Smell In Your Hot Water? Here’s 4 Ways To Fix It.

Imposed Current Anode (Titanium)

Adapted for residential water heaters in North America by Corro-Protec in 2006, imposed current anodes uses a much more efficient technology. Unlike the magnesium or aluminum water heater anode rod, this system of cathodic protection is built to last several years and require no maintenance. 

How Powered Anode Rod works

The imposed current anode is made from an insoluble titanium alloy and covered with MMO. In order to “activate” the protection, it is required to transmit a low voltage through, regulated electronically by a rectifier (to connect to a standard 120 V socket). The current allows complete polarization of the tank, providing a permanent protective layer against corrosion. With this type of water heater anode rod, it is possible to double the lifespan of your water heater, regardless of the composition of your water.

Contrary to popular belief, these anodes also have a shelf life that is determined by the quantity and quality of the materials used to make the MMO-coated titanium rods as well as the current transmitted by the rectifier. Corro-Protec water heater anode rod have been subjected to several tests in our laboratories in order to demonstrate their effectiveness and their life span. You can learn more on this in the blog entry: Tests of Powered Anode Rod.