How to Drain a Water Heater With a Clogged Drain Valve

Maintain the efficiency of your water heater by draining it once a year. Draining the heater removes the sediment buildup in the bottom of the unit. However, during the process of draining the water, sediment can clog the drain valve. The average handyperson can drain a water heater with a clogged drain valve, using a couple of tools.

Things You'll Need

• Garden hose
• Shallow pan
• Stiff bottle brush

Instructions

1. Shut off the circuit breaker to the water heater. The circuit breaker is inside the home electrical panel. If you have a gas water heater, shut off the gas valve to the water heater.

2. Turn off the water-supply valve to the water heater. The shutoff valve is located on the incoming cold-water pipe going to the water heater.

3. Attach a garden hose to the water heater drain valve. Place the other end of the hose outside. Make sure that no pets or children are around the garden hose -- the water that drains from your water heater can be scalding hot.

4. Open a hot-water faucet on a sink that is nearest the water heater. Turn the drain valve on the hot-water tank counterclockwise; this opens the drain valve and allows the water to start draining.

5. Check to see if water is draining from the hose outside. If sediment clogs are preventing the water from draining into the hose, step on the hose a foot away from the water heater. Sometimes this causes enough pressure to blow out the chunks of sediment.

6. Allow the water to drain using the hot water faucet you turned on earlier, if the water will not drain through the garden hose. Turn on the water-supply valve to the hot water heater when the hot-water faucet begins draining more slowly. The pressure of the added water should break up the clog. Shut off the water supply once the water through the garden hose is running clear, or if the extra water is having no effect on the clog.

7. Continue allowing the water to drain through the hot water faucet. Set a shallow pan near the water heater drain valve when no more water is coming out of the faucet. Have towel ready to clean up excess water.

8. Turn the water heater's drain valve clockwise to close the drain. Disconnect the garden hose. Move the shallow pan under the drain valve.

9. Open the drain valve slowly to allow water to flow into the shallow pan. Shut off the valve and empty the pan as necessary. Continue opening and shutting the valve until you can insert a small, stiff bottle brush into the drain valve. Move the brush in and out of the drain valve, reaching it inside as much as possible.

10. Reconnect the garden hose to the drain valve. Open up the water-supply valve to the water heater. Allow the water to flow until it runs clear from the garden hose.

11. Shut off the drain valve. Leave the water-supply valve on to refill the hot-water tank.

12. Shut off the hot-water faucet once there is a steady flow of water running through it. Disconnect the garden hose from the water heater's drain valve.

13. Allow the tank to fill with water. Turn the circuit breaker back on.

References

• District of Columbia Water and Sewer Authority: How to Drain Your Hot Water Heater