Water Heaters - Draining and Flushing the Water Heater Maintenance

A water heater’s tank can act as a settling basin for solids suspended in the water. It is therefore not uncommon for hard water deposits to accumulate in the bottom of the tank. To clean the tank of these deposits, it is recommended to drain and flush the water heater tank once a year. 

Draining

To drain the water heater, follow these steps:

  1. Turn off power to the unit. The electric heating elements will become damaged if operated without water.
  2. Attach a garden hose to the drain valve located at the bottom of the unit and direct that hose to a drain.
  3. Turn off the cold water supply.
  4. Admit air to the tank by opening a hot water faucet or lifting the handle on the relief valve.
  5. Open the drain valve.
    • Caution:  Make certain no one will be exposed to the hot water released by the valve. The water drained from the tank may be hot enough to present a scald hazard and should be directed to a suitable drain to prevent injury or damage.
    • Use a flat blade screwdriver to turn the brass drain valve or an adjustable open-end wrench to turn the black stem on plastic drain valves.

Flushing

Flushing should be done with an empty tank to promote additional removal of sediment. To flush the tank, follow these steps:

  1. Follow the steps above to drain the water heater.
  2. Once the water heater is empty, with the drain valve open and garden hose attached to the drain valve, turn on the cold water supply.
  3. Allow several gallons to flush through the drain valve and hose to an open drain.
  4. Turn off the water supply and allow any water remaining in the tank to drain.
  5. Repeat steps 3 and 4 until the water runs clear.
  6. Close the drain valve and fill the tank before returning power to the unit. The tank is full when water runs out of a nearby open hot water faucet.