How to Flush a Standard Water Heater

Flushing your water heater at least once a year is an important maintenance work that can help increase efficiency and lengthen the life of your equipment. Do you know that you can do this without having to call a Las Vegas plumber to help you? Learn how by watching our DIY video here.

Flushing your water heater (standard) is a task which should be completed at least once a year. However, most people seem to overlook this crucial part of your home plumbing upkeep. By not flushing your appliance, you risk the breakdown of your water heater due to sediment buildup; due to how hard the water is in Las Vegas, this makes it even more important to annually flush your heater.

Previously we showed you how to flush a tankless water heater; however, many homes still have a standard one. This task can be done without having to call a plumber in Las Vegas to do it for you. By following the simple steps outlined in this DIY video, you can successfully flush your standard water heater in no time at all.

Amount of Time

Required Tools


Step 1: The Gas Control Valve

The first thing you want to do is identify the Gas Control Valve on your standard water heater. This valve is located above the heat control valve. Turn the gas control valve so it is on Pilot. By turning the valve to Pilot it will prevent the water heater from creating more hot water while you are flushing it.

Step 2: Water Supply Shut-off Valve

Next we need to identify the water supply shut-off valve, and turn the valve a quarter-turn in any direction to turn off the water supply to the water heater. We don’t want the water heater to keep filling up with water as we are flushing it.

Step 3: Temperature and Pressure Relief Valve

Now, you need to find the Temperature and Pressure Relief Valve (aka T&P Valve). This valve is usually located on the top of the water heater. We want to turn the valve in an upward position. This will release the pressure that is already in the water heater.

Step 4: Replacing Plastic Valve

Most water heaters have a plastic valve that allows you to drain the water heater. However, we suggest replacing it with a Full Port Ball Valve. This type of valve makes it easier to flush your water heater each year. The reason this type of valve makes it easier to flush your water is because it has a water shutoff handle, as well as a larger opening to allow debris and sediment to be flushed out more easily. Replacing your plastic valve with a full port ball valve is simple, and doesn’t add on any extra time to flushing your water heater.

Step 5: Adding an Extender

When replacing the plastic valve with the full port ball valve, you want to have an extender ready for flushing your water heater. So, what you want to do is place a 3/4 4inch brass nipple into the valve to extend the valve out for flushing.

Step 6: Teflon Tape on Threads

Make sure that when you are adding your extender to the valve, that you add teflon tape to the threads of the brass nipple. This provides a better seal when flushing the water out your heater.

Step 7: Air Lock the Water Heater

So, now that we have the extender ready, we need to go back to the T&P Valve and we want to turn it back to a downward position. This will prevent any further pressure buildup when flushing. This will essentially air lock the water heater.

Step 8: Taking the Plastic Valve Off

Now we are ready to take off the plastic valve, and install our full port ball valve. So, take your channel locks and turn them counter clockwise when taking off the plastic valve. Because water heaters are usually in a tight space you are going to have the reverse the channel locks back and forth when taking off the plastic valve.

Step 9: Installing Full Port Ball Valve

As you take off the plastic valve, you will have some sediment and water leak out; however, due to the T&P valve air locking the water heater, you won’t have water just shooting out. Now that the plastic valve is off, it’s time to install the full port ball valve. Stick the extender into the opening where the plastic valve used to be, then take your channel locks and turn the valve clockwise until the valve is secure.

Step 10: Turning the Full Port Ball Valve Off

With the full port ball valve installed, we are now ready to proceed with turning the valve off and installing our hose. This step has three sub-steps listed below.

A) First you need to turn the valve into the off position. This prevents water from flowing out as you are installing your hose.

B) Next, take the cap off the valve. It usually has a chain attached to the valve, so when you take it off it doesn’t get lost.

C) Finally, attach your hose to the valve. This hose will be funneled down to your storm drain so you can safely dispense of the water and sediment within the water heater.

Step 11: Turn T&P Valve Upward

Again, we are going back to the T&P valve, and this time we are turning it in an upward position. This will apply the pressure necessary to flush out the water.

Step 12: Flushing the Water Heater

Now for the big moment! Turn the ball valve on and watch as your water heater begins flushing out the sediment and buildup inside of it.

Step 13: Curling the Hose

If this is your first time doing this, we suggest curling your use up at the end of your driveway so you can see the sediment and mineral buildup that is being flushed out of your water heater. It will most likely shock you to see how much buildup there actually is. As previously mentioned, due to the water hardness in Las Vegas, sediment and other mineral buildup is a major problem for many home water heaters. By being able to see the sediment that is coming out of your water heater, you can get a better understanding of why it is so important to flush it yearly.

Step 14: Power Flushing

After about 30 minutes (or less) the water coming out of the heater should begin to stop. When this happens, it’s time to power flush the water heater. This is done so that we can remove the majority of the sediment and buildup that is just sitting at the bottom of the tank. The water doesn’t come out with much force when first flushing it, so that is why we need to power flush it.

A) To do this, all you need to do is turn the water supply back on to the water heater. This is when you will see a huge amount of sediment and buildup coming out. You want to power flush your water heater for about a minute. Power flush the water heater until the water is clear.

B) Go back to the curled up hose at the end of your driveway and see how much sediment comes out. Here is a plumbing tip for you: if the water coming out has an orange tint to it, this could mean the water heater is already breaking down. If this is the case, we suggest calling an experienced Las Vegas plumber to help you with replacing your water heater, or possibly fixing your current one.

Step 15: Shut Off the Water Drain Down Valve

Now that we power flushed the water heater, and got the sediment and buildup out of it, we need to shut off the water to the drain down valve so we can disconnect the hose. Once the hose is disconnected replace it with the cap.

Step 16: Leave the T&P Valve On (Upward Position)

Leave the T&P valve on in an upward position. This is to allow air to escape when your water heater is filling back up with water. If you forget to do this step, you will have to go to every fixture in the house and turn them on to allow the air to escape.

Step 17: Turn the Gas Control Valve On

In the very beginning we told you to turn the gas control valve to Pilot as we flushed your water heater. Now that the water heater is flushed, you want to go back and turn the gas control valve back to the On Position. If you forget to turn this back on, your water heater will not be able to heat up the water that is in the tank.

Set Aside Enough Time

Make sure that you set aside enough time for your water heater to fill up and heat up. It takes about 45 minutes to an hour for the water heater fill up and be ready for use. So plan accordingly.

And there you have it! You have learned how to properly flush your standard water heater. Remember to clean up and properly store your tools so they are available the next year when you need to flush your water heater again.

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If you need help with this process, have a plumbing emergency, or any other plumbing problems which require professional service, Pure Plumbing is always available 24/7. Call us at (702) 710-7388 to get help immediately or to schedule an appointment with a qualified Las Vegas plumber. We are here to help!

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