How Do Anode Rods Work in a Water Heater?

How Do Anode Rods Work in a Water Heater?

According to electrochemical principles, when two different metals are immersed in water the active one will corrode away to protect the less active metal. The anode rod is made from metal with a more active voltage and higher electrochemical potential than the metal of the tank, which is typically made from steel. This means the anode rod’s metal will give up electrons and corrode before the tougher steel metal of the tank will. As this lesser metal corrodes, electrons are distributed into the tank, creating a more favorable chemical environment that prevents the corrosion of the steel tank itself.

Magnesium or aluminum rod is the main rod used in a water heater, they are active comparing with the water heater tank which is in steel material. When a water heater tank is filled with water, an electrolytic reaction occurs, the sacrificial anode rod “sacrifices” to protect the water heater tank from corroding.