Water heater manufacturers recommend flushing sediment from your water heater periodically. How often you should flush your water heater depends on the quality of the water in your area but most experts agree once a year is a good guideline. When flushing your water heater there is a danger of being scalded so be very careful and keep children and pets away during the procedure.
Sediment is sand or grit that has gotten into the municipal water mains. It also can be comprised of scale and mineral deposits. Over time your water heater will accumulate this sediment reducing the amount of water your heater tank can hold, reduce the efficiency of the unit and corrode the unit. It can also clog the drain valve.
Cleaning the sediment from your unit is fairly easy but there are some important first steps to remember. If your water heater is gas set the gas valve to “pilot” to prevent the burners from coming on while you are flushing it. If it is electric be sure to turn off the circuit breaker. With an electric water heater if the water level drops below the heating element and the elements come on they will burn out quickly.
Next connect a garden hose to the drain valve at the bottom of the tank. Make sure the discharge for the hose is in a safe area away from pets and children to prevent injuries from scalding. Close the shut off valve to the cold inlet to the water heater. Carefully open the pressure relief valve at the top of the tank by lifting the lever up and leave it in the open position. (Be careful if your pressure relief valve does not discharge into a pan or to the exterior or you will flood your floor).
Open the drain valve at the bottom of the water heater and allow the water to flow through the garden hose. It is recommended you have the water drain into the yard as iron sediment can stain your concrete on your driveway and walkways. If the sediment is clogging the drain valve close the pressure relief valve and turn the cold inlet back on to help power flush it. If this does not clear the drain remove the hose and use a screw driver to break up the chunks of sediment in the drain valve.
You’ll know you are done when the water being discharged runs clear. At this point turn the valve off and remove the hose. Turn the cold inlet valve back on. Open a faucet in the house and let it run until the air gets out of the line. Then you can turn the heater back on and if it is a gas unit relight the pilot light.