Tank water heaters consist of a glass-lined or vitreous enamel-coated steel tank covered by an insulated metal jacket. They are gas-fired, oil-fired or electrically heated.
Watch for signs of leakage on the bottom of the tank, such as rust or water stains at fuel burning components or on the floor. Leaking tanks cannot usually be repaired and therefore, must be replaced entirely.
As part of a maintenance plan, the tank should be drained regularly to remove sediment and rust. Check the temperature/pressure relief valve ( sometimes at the top or on the side of the tank), and for a discharge pipe that extends from the valve to a few inches from the floor, a floor drain or the building exterior, depending on your local code requirements. this pipe should never be leaking or dripping water. Monitor for soot or carbon deposits. Any soot or carbon that has accumulated below the draft hood of a water heater may indicate a restricted flue or chimney, or more commonly, back-drafting caused by insufficient make-up air.