How To Drain A Water Heater Tank

We can all agree that a hot water heater is a pretty important part of your home. After all, you wouldn’t be able to do dishes, wash laundry, or take a relaxing shower if you didn’t have hot water.

Sadly, it’s also one of the most neglected appliances around a household. To put it simply, not many people think to check their unit until there’s suddenly an issue where it quits working or starts making noises.

The good news is that a little bit of water heater maintenance once or twice a year can ensure your family has a steady stream of piping hot H2O whenever you need it most.

And where does that all start? By draining the water heater and flushing out any accumulated sediment. Here is what you need to know about the process and what it means for your hot water heater.

water heater

The process of draining a hot water heater isn’t all that difficult, but you will need to follow a few steps to ensure it is successful. The main goal here is to flush out any sediment, which can build up and cause damage to your unit.

Water heater tanks should be flushed about every six months, especially in areas with hard water.

attached hose to water heater for draining

Step One: Hook Up a Garden Hose to the Drain Valve

This is designed to direct the water away from your unit and out into your yard or into a bathtub where it can drain appropriately. This is a pretty crucial step, so make sure your hose connections are tight.

Step Two: Do a Slight Flush While the Water is Still On

Open the valve for 10 to 15 seconds, allowing the water to rush out through the hose. If there is a fair amount of sediment in the tank, a fair amount should come out during this process. Keep doing this once or twice more.

Caution: the water that comes out is very hot and can burn people and pets so be careful where the hose drains to.

turn off water supply to water heater

Step Three: Shut Down the Hot Water Heater

Now that you’ve done a couple quick flushes, it is time to drain the whole tank. If your hot water heater is a gas unit, shut off the gas to the unit.

If it is electric, flip the breaker switch on your household panel. Use the valve on the cold-water pipe to cut off incoming water to the appliance.

If you cannot find this valve or one is not installed, be prepared to turn off water to the whole home.

Next, shut off the water supply line into the tank (shown above).

Step Four: Start Draining the Tank

Open the valve and start letting the water drain out from the unit through the hose.

If it is running too slowly, you can slightly disconnect the hot water pipe that leads from the heater to the rest of the plumbing in your home.

Doing this releases the vacuum pressure inside the tank, which causes the speed of the drainage to increase.

Keep going until only a slight trickle of water comes out.

turn on water supply to water heater

Step Five: Rinse and Flush the Tank with Fresh Water

With the hose still attached to the drain valve, turn the valve at the cold water pipe back on or restore water to the whole home.

This will fill the tank with cold water, which won’t heat because your power source should still be off.

Continue to run the water and drain the tank for several minutes, allowing any additional sediment to flow out. Not quite sure how this works? Think of the incoming water as a way to loosen and spray out the mineral buildup inside your hot water heater tank.

Step Six: Reconnect Your Unit

Unhook the garden hose and close the drain valve.

Reconnect the hot water pipe to the house and make sure it is as tight as possible to prevent leaks.

Fill the tank all the way up with cold water.

Check the drain valve for any leaks, which can be common and cause bigger problems if left unattended.

Go inside to a bathtub or shower and turn the hot water faucet on, letting it run until it is apparent that all of the air bubbles in the line are gone.

Then relight the gas pilot or turn the electric back on to the unit.

From there, it takes about 45 minutes to an hour for your tank to be fully refilled with piping hot water.

flush sediment from water heater

What Does It Mean to Flush a Hot Water Heater?

If your plumber tells you that you need a water heater flush, you’ll want to pay attention to what we’re about to describe.

While it does involve draining your unit, there are a couple more steps involved.

Usually, this process is reserved for older units or those in areas where sediment buildup is especially bad due to hard water mineral content of the local water supply.

Flushing a hot water heater starts with draining the tank as much as possible with the existing drain valve and a hose.

If this is not possible due to a buildup of sentiment or other problems with the valve, the valve must be removed and replaced with a ball port valve to allow to flushing the tank.

While this is something you might be able to attempt yourself if you’re plumbing savvy, it is definitely not recommended for beginners or those with very minimal technical skills.

Why? Installing the plug incorrectly can cause leaks or floods which can create bigger problems and permanently damage the area surrounding your hot water heater.

If you must do it yourself, here’s the steps to take:

1. shut off water supply valve to tank (or water main to house).

2. open a hot and cold water faucet in the home to bleed pressure out.

3. have your port valve and nipple ready to install (you won’t have much time).

4. shut off the hot water exit valve from the tank.

5. place a bucket under the existing hose bib.

6. remove old hose bib from tank (water may start coming out).

7. install new port valve as fast as you can.

The full port ball valve will allow for better drainage and the loosening of sediment that could clog the standard valve.

After the new valve is in place, open the exit and water supply valves again. Check for leaks.

Now you can flush out the tank several times using the incoming cold water and finish the process as described above.

We offer a professional water heater flush for conventional water heaters and descaling service for tankless water heaters.

How Long Does It Take to Drain a 50-Gallon Hot Water Heater?

Draining your hot water tank actually takes a lot less time than you might realize.

If you’ve loosened the hot water exit pipe to unlock that vacuum seal on the tank, it should only take between 5 and 10 minutes for the unit to fully empty.

Of course, this assumes that there are no clogs in your drain valve or other issues keeping the water from flowing out at a standard rate.

See our service pages for water heater repair & installation and tankless water heaters.

In some cases, the process could take as long as 20 to 30 minutes.

However, it is important to note that a slowly draining tank is also a symptom of a high sediment buildup, so plan to do a couple extra rounds of clean water flushing when you get to that step in the process mentioned above.

Do I Need To Drain My Hot Water Heater?

It is pretty important to drain your hot water heater at least once a year, but preferably twice a year.

This is especially true if your area of the country has particularly hard water or a lot of natural minerals.

Sediment buildup is the arch nemesis of your hot water heater and ignoring it can really cause expensive problems down the road with your appliance.

Note: a water softener can remove those hard water minerals and extend the life of your water heater, plumbing pipes, and other appliances.

What if you don’t have the time or urge to do this yourself? Consider hiring a local plumbing expert to handle it for you.

Why Is It Taking So Long to Drain My Hot Water Heater?

As mentioned above, a hot water heater that takes an incredibly long time to drain likely has a large amount of sediment buildup that’s clogging the drain valve.

However, here are a few troubleshooting tips to consider.

The Valve Has Other Issues

Valves are mechanical. And, like anything with moving parts, they can break for an unknown amount of reasons.

If you’ve never used the drain valve on your hot water heater, it could be broken and you might not even notice it.

Those that suspect this issue should contact a plumber immediately to have it switched out.

Sediment Buildup is Clogging the Valve

This is usually the most common culprit of a slow draining hot water heater.

If this is your experience and the mechanical workings of the valve itself seem fine, keep trying to drain the tank.

It might take a while, but eventually flushing out the tank will improve the situation.

You Forgot to Slightly Unhook the Hot Water Pipe

Hot water heaters create an interior vacuum for a reason. If you don’t break this seal, the water will trickle out the drain valve and down the hose at a very slow rate.

Unhooking or just loosening the pipe slightly and letting air in will cause the water to move much more quickly.

Just be ready for that initial gush and double check your hose connection at the valve before you do to stay on the safe side.

Wrap Up: Draining a Hot Water Heater

It might seem like draining your hot water heater every 6 to 12 months feels like a hassle.

While we agree that there are far other important activities to do around your home, this is one of those maintenance tasks that can help fend off a costly repair in the future.

Not only that, draining your tank is a good chance to see if there are any problems or leaks that you might have missed since the last time it was serviced.

Not sure you want to go through this process on your own? Don’t worry about it. Our dedicated and knowledgeable team at RT Olson Plumbing is here to help. We offer a Water Heater Flush Service.

Contact us today to schedule a water heater service appointment.

See our service pages for water heater repair & installation and tankless water heaters.

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Owner - Operator at RT Olson Plumbing
Bob Olson has over 18 years experience in all aspects of residential and commercial plumbing. He's a 4th generation plumber. With over 500 five-star customer reviews, he runs one of the best-rated plumbing companies in Corona, CA.
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