What is an anode rod?
A sacrificial metal rod, typically made of magnesium or aluminum, installed inside a water heater tank that corrodes to protect the tank steel from rust and extend the heater's life.
An anode rod is a metal rod suspended inside a water heater tank that attracts corrosion before it can damage the tank itself. Made from magnesium or aluminum, the rod sacrifices itself by corroding in place of the steel tank walls. As mineral-laden water enters the tank, the anode rod oxidizes preferentially, leaving the tank structure intact.
Over time, repeated exposure to heat and water minerals depletes the anode rod. Once significantly worn, it can no longer protect the tank. A corroded or consumed anode rod allows rust to develop directly on the tank interior, leading to leaks and early failure of the water heater.
Inspection and replacement of the anode rod is a standard maintenance task. Plumbers typically check its condition during routine service or when addressing water heater problems. Replacing a worn rod before the tank begins to rust can add years to a water heater's operational life, making it one of the most cost-effective preventive measures in water heater maintenance. The replacement frequency depends on water chemistry, temperature settings, and usage patterns.