Water Heater Maintenance:

Two times a year:

Drain and flush sediment, which reduces efficiency and causes rumbling, from the tank. (Do this monthly if the level of sediment in your water is high.) To drain the tank, turn off the water supply at the tank top, hook a hose to the spigot at the base, open a hot-water tap anywhere in the house and open the spigot. When the tank is drained, turn on the water supply at the tank top and let it run until the water draining out is clear. Close the spigot and turn off the tap.

Once a year:

Check the pressure-relief valve to make sure this crucial safety device isn't clogged. To relieve any over pressurization in the tank, place a bucket beneath the copper overflow pipe where it hangs near the floor. Carefully push the relief valve at the top and a burst of hot water should spray out of the pipe. If not, the valve needs to be replaced.