Twice a year, drain and flush sediment from the water heater tank.
To drain your water heater start by turning off the heater and letting the tank cool; then shut off the water supply. If gravity is on your side, connect a hose to the drain cock and run it to a floor drain. If you don’t have a drain, send the water to a sink or bucket using a drill pump. Draining 3 gallons is usually enough, but you may have to fill and flush a few times until the water’s clear.
Once a year, check the pressure-relief valve. This is a crucial safety device and it must not become clogged.
A faulty relief valve can — and has — caused water heaters to blow up! Remember that the appliance is under a lot of pressure. The valves allow a release of that pressure, safely. If they aren’t working, however, you could have a serious problem on your hands!
Testing the valve is an easy procedure. Turn off the power and the cold water supply to the water heater first. Next, locate the valves on each side of the tank, plus the one on the bottom. Place a bucket on either container under the valve. Open it up all the way. Release the valve and watch to see if water continues running out. The valve should close on its own and stop draining water. If the valve doesn’t close, it must be replaced.
To replace the valve, begin by purchasing a replacement valve at a hardware store. Next, drain your tank part way. Use a pipe wrench to remove the valve. Screw in the new valve and turn on the water heater (this allows the tank to re-pressurize). Turn off everything and repeat the test process to make sure the new valve is working.