Anode rod

A storage tank is glass-lined steel, and the lining has seams and pinholes where water can reach the steel. The anode rod is a more reactive metal suspended in the tank, so corrosion attacks the rod instead of the tank wall: the rod is consumed and the tank survives. Bradford White's manual calls for inspecting the combination anode rod and hot-water outlet nipple periodically, every two years, and replacing it when necessary.

The anode material matters: magnesium protects aggressively and is the common factory fit, while aluminum variants are listed in Bradford White's Canadian parts list for some water conditions. Powered anodes exist for specific corrosion problems but are assessed per installation.

Very soft water, around 2 to 25 mg/L hardness, is more aggressive to the tank's steel than hard water, which is why anode condition matters more here than descaling. A depleted anode is the usual reason a tank starts to rust from the inside, and the first sign is rusty water at the taps before the tank itself fails.

Replacing a depleted rod is routine while the tank is sound; ignoring it ends in a leaking tank that cannot be repaired. The maintenance visit measures what is left of the rod rather than guessing by age.