How to Drain Water Heater

If you need help to drain a water heater, the guide below should get you going.

A garden hose and maybe a screwdriver is all you need if you don't run into any problems.

Just follow the guide below and I'll try to cover any problems you may run into.

The drain valve is located at the bottom of the tank and will be made of plastic or brass. 

More information about water heater drain valves.

The pic on the left is a brass water heater drain valve.

As you can see, it is opened and closed with a flat screwdriver.

This is a plastic hot water heater drain valve.

This plastic drain valve is easy to turn on and off, however, these valves are easy to cross thread when attaching the drain hose.

This water heater drain valve opens by screwing to the left after the drain hose is connected.

These valves are a real pain to use. As you open them up the drain hose will twist into knots.

Worst of all, its possible for one to pop off of the nipple its attached to and cause burns and/or flood your house.

Its a good idea to run all of your hot water out of the tank before you drain it if you have one of these valves.

Open this valve only far enough for water to drain from the tank.

Don't try to open it any more than necessary. Opening it to far will increase the chance of it coming off.

Unless you are replacing your water heater, I would suggest replacing this valve with a brass drain valve.

Drain Water Heater

Step One

Gas water heater- Set the on/off control knob to the off position.

Electric water heater-Turn the power off in the breaker box.

Be absolutely sure that you shut off the proper breaker. If the power is when the tank is drained the heating elements will blow and must to be replaced.

If you can't identify the water heater breaker, shut off all of the double breakers. 

Open a hot water faucet in your home and let it run until it runs cold. This will eliminate any chance of getting burned if there is a problem. Also, hot water will kill your grass.

Step Two

Attach a garden hose to the drain valve at the bottom of the tank. Position the hose outside removing any kinks.

Slowly open the drain valve until water is running out of the hose. This will remove any sediment that may have collected in the valve.

Shut the water off to the water heater. The water shut-off valve should be located above water heater on the cold water line.

remove faucet aerator

Step Three

Remove the aerator from your kitchen faucet.

Open the hot water side on your faucet.

Opening the faucet will allow air into the water heater so it can drain.

Tip: If your system has an older style pressure relief valve, you can use it to let air into the tank. Raise the handle all the up and it will lock into place.

Newer relief valves will not lock open. 

Why open the kitchen faucet and remove the aerator?
Because of hard water, most water heaters have calcium deposits in the tank. They look like small rocks. 

When the tank is disturbed, such as draining and filling, these deposits can travel through the water pipes and clog the faucets, appliances (dish washer, clothes washer), and the under sink shut off valves.

After the tank is refilled, we will send all the water to the kitchen faucet. If their is a problem, this faucet is simple to unclog.

attach garden hose to drain valve

Step Four

It will take 20 to 30 minutes to empty the tank.

If you have a problem getting the water to drain, turn off the hot water side on your kitchen faucet. Turn the water back on to your water heater leaving the drain valve open.

When the water is running strong through the drain hose, turn the water off again and open the hot side of your kitchen faucet.

Water Heater Draining Problems

My water heater drained for a while but then it stopped and I know the tank is not empty, what to do?

1. First, check to see if someone turned the hot water side of the kitchen faucet off while you were not looking. It must have air to drain.

2. Your drain valve may be clogged with debris, rust and calcium deposits.

If the tank has drained very little, refill it leaving the drain open and with the        faucet closed.

The water pressure should push the debris through the drain line.

3. If a lot of water has drained from the tank, you can try the steps below instead of refilling the tank.

Close the drain valve and remove the hose. Place a small bucket under the drain.

Using a stiff wire, open the valve and use the wire to try to loosen the debris.

Be ready to turn the drain valve off until you reattach the hose.

4. When trying to drain a water heater, and it clogs, you can use a washing machine fill/supply hose to push the debris out of the drain.

These hoses have 3/4 in. female connections on both ends. Attach one end to the water heater drain valve, the other end to a garden hose.

Run the garden hose outside and connect it to an outside water faucet. Be sure your drain valve is open.

Turn the water faucet on for 10 to 15 seconds. Disconnect the hose from the faucet and drain the tank

Leave the washer fill hose as is in case you need to repeat the process.

My drain valve keeps clogging up and I can't drain my tank.

1. You could disconnect the plumbing, gas/electric, and roll the water heater outside with a set of hand trucks.

Lay it on its side and let the water drain out of the top of the tank.

2. You can drain a water heater with a ball valve. This is really the best thing to do.

Even if your replacing your old water heater you can remove it when            your old tank is empty and install it on your new water heater.

Use it to flush your new water heater every three or four months. It will last years longer.

Learn more about ball valves.

How to install a ball valve with a full tank of water.

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