With proper maintenance, a quality water heater can last about 15 to 20 years. However, if the water heater anode rod is not regularly inspected and replaced, the water heater tank might rust out before it reaches 10 years of service. The anode rod – a long metal rod, usually made of magnesium or aluminum – is used to attract iron, limestone, and other minerals in water that would otherwise rust the inside of the water heater’s steel tank. The anode rod gradually corrodes in place of the steel tank, extending the water heater’s lifespan. And, in most cases, owners will need an anode rod replacement only about once every 3 to 5 years. Considerations before replacing the anode rod include determining if a magnesium, aluminum or zinc anode rod should be used, the hardness of the water, and what types of metals and minerals are present in the water. Learn about replacing the anode rod to extend the lifespan of a water heater.