The Anode Rod
LOSS OF THE RUST PREVENTOR DEVICE CALLED THE ANODE ROD:
All glass-lined water heaters have rods of solid metal, usually magnesium suspended in the tank. The sole purpose of these rods is to slowly corrode away so that the tank will not. Called sacrificial anodes, the rods sacrifice” themselves to protect the steel tank from rusting.
Inspect the anodes regularly and replace when needed. Generally every 3-5 years in hard water areas and where acid water is a problem, or water is softened, inspect every 1-2 years.