What is an anode rod?
A metal rod, typically made of magnesium or aluminium, inserted into a storage water heater tank that corrodes preferentially to protect the tank from rust and extend its operational life.
Water heater tanks hold water containing minerals and oxygen that naturally promote corrosion. An anode rod sits inside the tank and sacrifices itself through a process called cathodic protection. By corroding instead of the tank walls, the rod stops rust from forming inside the vessel, which would otherwise create holes and leaks that end the unit's life.
Most anode rods are made of magnesium or aluminium. Magnesium corrodes faster but offers stronger protection, while aluminium rods last longer but are less effective in high-temperature water. The rod gradually wears away as it corrodes, leaving a thinner core or disappearing entirely. In Klang Valley's hot and humid climate, where mineral-heavy water accelerates corrosion, anode rods wear out faster than in cooler regions.
When an anode rod is completely depleted, the tank itself becomes vulnerable to rust. A failed anode rod is one of the primary reasons storage water heater tanks fail prematurely. Regular inspection and replacement every 3 to 5 years (depending on water quality and temperature) is essential to maximize tank life. Technicians inspecting heaters will check the rod's thickness to assess tank protection status.
If you suspect your water heater tank needs an anode rod inspection or replacement, contact a qualified technician through local water heater installation and repair services.