Most water heaters have a sacrificial anode rod that protects the inside of the tank from corrosion. Made of Aluminum, Magnesium, Zinc or a combination, these rods attract minerals in the water that would normally attack the inner tank therefore prolonging the life of the tank. Having the rod changed by a professional or changing it yourself is IN MY OPINION THE BEST preventative maintenance you can do for your water heater. Use a 6 point 1&1/16 inch socket with ratchet or impact wrench as they are difficult to remove. Bradford White tanks are more difficult as the anode is attached to the hot outlet. #plumbing #viral #maintenance