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What is an Anode? Why is one in my Water Heater?



A hot water anode or “sacrificial anode” is essential in keeping your Hot water tank on its best condition and extends the lifespan of your water tank. As it prevents corrosion of the tanks.


Your water heater is one of the most hard working appliances in your house, whilst it is a quiet achiever, it no doubt brings you the comforts of the modern era! Imagine life without out one?


As a Plumber I receive calls every day of people who require a hot water heater replacement, this replacement is often being done prematurely due to the fact that they have not serviced and replaced the sacrificial anode on thier water heater. .


Anodes are steel core rods surrounded with either magnesium, aluminium or zinc and are installed from the top of hot water tanks, It’s similar to sacrificial anodes used in various types of vessels such as ships, barges, tankers and also used around docks and harbors.


Through a process called electrolysis the “sacrificial anode” will corrode in place of the heater’s exposed steel. This happens whenever metal needs protection from the water and occurs when two pieces of the submerged metal react to the voltage.


During this process the more reactive metal Zinc, magnesium or aluminium will corrode before the less reactive metal like steel. These metal Anodes act as a  protection for the heater.


Anodes should be changed every 3-4 years but would vary on the quality of water on different areas. Once fully corroded, the anode will cease to protect the tank, which will become a problem if left uncorrected.


It is highly recommended to have these anodes replaced as once they get fully corroded it will lead to an expensive tank replacement prematurely.

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