How to Drain and Flush a Water Heater

Run the garden hose outside, or to a floor drain, so that the water can exit the water heater without spilling in the home.

Next, turn on a hot water faucet somewhere in the house, e.g. sink or tub. This will allow air to enter the hot water pipes and enable the water to drain from the water heater tank more easily.

Once the preparation work has been completed to drain and flush a water heater, open up the drain valve and allow the water to drain from the water heater. Do not be surprised to see discolored water draining from the water heater. The discoloration is due to the mineral and sediment deposits in the water heater. After draining the water heater, turn the cold water inlet supply valve back on and allow the cold water to enter the water heater and exit the drain valve. Continue to flush the water heater until the water exiting the drain valve becomes clear.

Once the water drains clear from the water heater, turn both the cold water inlet supply line valve and drain valve off and remove the garden hose. Also turn off the hot water faucet that you had earlier turned on inside the home.

Next, turn the cold water inlet supply line valve back on and allow the water heater tank to fill.

Once the water heater has filled, place a bucket underneath the pressure water heater relief valve and flip the lever up to discharge a little water from it. Then close the lever down and confirm that no more water drips from it. The pressure water heater relief valve, as the name suggests, prevents the pressure from building up too high in the water heater. In the event that the pressure or temperature within the water heater does exceed the rating capacities of the pressure relief valve, it will automatically open up and reduce the water pressure. When this occurs, unfortunately, water will spill on the floor if it is not designed to feed into a floor drain.

Upon confirming that the water heater pressure relief valve is working properly you can turn the electric or gas back onto the water heater. And with the power turned back on, you’ve completed the process of draining and flushing a water heater.

Again, it is important to drain and flush water heaters annually in order to improve the operating efficiency of it, extend the life of the water heater, and provide clean hot water to the home. So don’t forget to include a line item in your home maintenance schedule to drain and flush water heater annually.