How to flush a water heater

When it comes to doing household chores, flushing your hot water heater is easy to overlook. I know I never thought about doing it until Jeremy included it in his truly handy home maintenance checklist.

But regularly flushing out your hot water heater is an important task. Getting rid of the gunk and mineral deposits that accumulate will help your hot water heater run more efficiently as well as prolong its life, saving you money in the long run.

After living in my home for several years, I figured my hot water heater was due for a flush and decided to tackle this chore. Fortunately, it turned out to be super easy. Excluding the time I was waiting for the water in the tank to cool, it took me all of about 20 minutes.

I documented the process as I did it, just in case you need to do likewise. Maybe this post will inspire you to finally knock this to-do off your list this weekend.

How Often Should You Flush Your Hot Water Heater?

Depending on your model, aim to flush your hot water heater every one to three years. Really, the job is so easy, it wouldn’t be a bother to do it at least once a year.

How to Flush Your Hot Water Heater

Hot water heaters come in two varieties: gas and electric. I’ve got the gas variety, so these instructions will be geared towards flushing a gas hot water heater. The biggest difference between gas and electric is that with gas, you’ll be turning off the gas to your appliance; with an electric, you’ll be turning off the electricity.

1. Turn the Knob on Your Hot Water Heater’s Thermostat to “Off”

How to flush a water heater

The thermostat on a gas hot water heater is usually found near the bottom of the tank. Other sources I ran across said you could get away with just setting your thermostat to “Pilot.” I decided to be extra safe and turned it off completely. If you turn your hot water heater off, and you have an older model, you’ll have to re-light your pilot light.

If you have an electric hot water heater, you’ll want to find your home’s breaker box and turn off the switch that gives power to your hot water heater.

2. Turn Off Gas to Hot Water Heater

How to flush a water heater

If you have a gas hot water heater, find the gas pipe leading to your thermostat and pilot light and turn the valve to the off position. If you decide to just turn your thermostat to “pilot” you won’t need to do this step.

3. Turn Off the Cold Water Supply to Hot Water Heater

How to flush a water heater

The cold water valve is usually near the top of your hot water heater. Turn it to off.

4. Turn on the Hot Water in a Sink or Tub

How to flush a water heater

Leave them on during the entire flushing process. This will help prevent a vacuum from forming in the lines while you’re draining the hot water tank.

5. Connect Garden Hose to Drainage Spigot

How to flush a water heater

Before you turn on the spigot, make sure the other end of the hose leads outside or at least into a bucket. If your hot water heater is in the basement, you may need to get a portable pump in order to pump water out of the basement and to the ground floor.

6. Turn on Spigot and Drain

How to flush a water heater

Drain your tank until the water runs clear and no longer has sediment. If your tank has a lot of sediment, you may need to drain it completely. As you can see in this picture above, the water when I first started draining was a bit brown and there was a lot of sediment at the bottom of the bowl.

8. Flush

How to flush a water heater

To flush your hot water tank, simply turn on the cold water spigot leading into your hot water tank. Let it run for a few minutes until the water exiting your hose runs clear.

How to flush a water heater

This may take a bit. While the water might be running clear and isn’t brown, you may still have some sediment. Here’s a picture of the water coming from my tank when I first started flushing:

How to flush a water heater

As you can see, I still had some sediment (can be seen at the bottom) coming out. Continue flushing until you have very little or no sediment in your water. Turn off the cold water spigot leading into your hot water tank.

Finishing Things Up

  • Turn off the drainage spigot and disconnect hose.
  • Turn off the water on your sink or tub that you turned on at the beginning.
  • Turn on the cold water spigot leading to your hot water heater.
  • Turn on the hot water spigot of a sink or tub to get the air out of the system. Cold water should be coming out of the faucet at this point. Turn it off.
  • If you shut off the gas to your hot water heater, turn it back on.
  • If you turned the thermostat off on your hot water heater, re-light the pilot light (it’s easy — I may do a post on this in the future), and then turn it to on.
  • If you have an electric hot water heater, flip the breaker switch on your electrical panel that gives power to your hot water heater.
  • Wait about 20 minutes for the water to heat up. Turn on a hot water spigot somewhere in your house to ensure hot water is coming out.

Boom. You’ve flushed your hot water heater. Put it on your calendar to do it again in a year.


Every homeowner knows how important it is to clean and maintain your systems and appliances. However, many homeowners don’t know that flushing a water heater every year can remove a build-up of sediment from the bottom of the tank. Flushing sediment can improve a water heater’s lifespan and efficiency. Sediment can create a barrier between the heating elements of the water heater and the water, making it harder to heat your home’s showers, dishwasher, and laundry. By flushing sediment out of your water heater, you can save money and heat your water faster.

Learn how a how a water heater works to better understand how to flush your tank.

1. Turn the Water Heater Off

If you have an electric water heater, turn off the power switch. If your water heater is a gas heater like the one shown in the photo above, turn your thermostat to the “pilot” setting. This turns the heating element off in your water heater so your water can cool down. Before starting this maintenance project, make sure no one in your home is trying to take a shower, wash dishes, or run a load of laundry.

2. Turn the Cold Water Valve Off

Turn the cold water valve off. A water heater moves hot water through your home when cold water is brought into the tank, displacing the hot water. Without the cold water coming into your tank, you can completely drain the tank of water. If you miss this step, you’ll end up having water continually move into the tank and drain, which could cost you a pretty penny on your water bill.

3. Let the water cool.

Don’t drain scalding hot water. Let the tank cool after turning off the heating elements. This can take up to two hours for some larger water heater tanks.

4. Attach a drain or garden hose to the drain valve on the side of the tank

Find the drain valve on the side of your water heater and attach a hose. Make sure the hose is threaded on completely or you could end up with leaks as you drain your water heater tank.

5. Place the end of the hose in a bucket or drain.

Don’t flood your home! Make sure to put the end of the hose in a heat-proof bucket or down a drain. Before you begin draining the water heater, make sure that your drain isn’t going to overflow.

6. Turn on a faucet (or two)

Opening faucets around your home can stop a vacuum from forming within your pipes. Turn your faucets on the “hot” setting and let them run. You won’t see a lot of water coming out of them because you’ve turned off the cold water valve to your water heater, so no warm water is being displaced.

7. Start draining the tank by turning on the drain valve.

Using a flathead screwdriver, turn the valve on slowly, making sure that there aren’t any leaks and the bucket or drain you are draining the water into isn’t going to overflow.

8. After the water heater tank has finished draining the sediment, turn the drain valve off, remove the hose, turn the cold water valve on, and turn the heating elements in the water heater back on.

After you’ve completely drained the tank, and removed the sediment within your water heater, you’re almost done! To fill your tank again, turn the drain valve off, and remove the hose. Turn the cold water valve back on and turn the heating elements back to the on position.

Make sure that your taps are still on, and once they return to a normal flow, turn them off. You’ll want to wait about 30 minutes to test for hot water. The water heater should have heated the gallons of water within the tank again, sediment free! Need more information on water heaters and why yours might not be functioning as well? Use our article about common water heater problems and how to decode them!

Landmark Home Warranty offers plans that cover water heaters (up to 70 gallons) if they fail from normal wear and tear. Some plans even cover for sediment damage! If your water heater has stopped working and you have a Landmark Home Warranty protection plan, you could get it repaired or replaced for just the cost of a service call fee if it is covered under the terms of your contract. Give us a call today or open a service request online.

Aaron Stickley is a licensed plumber with 15 years of experience in commercial, new residential plumbing, and residential service and repair. He started his own residential service and repair plumbing business. Aaron's articles about plumbing on The Spruce span four years.

  • Pin
  • Share
  • Email

The Spruce / Kevin Norris

  • Working Time: 1 – 2 hrs
  • Total Time: 1 – 2 hrs
  • Skill Level: Beginner
  • Estimated Cost: $0

Most water heater maintenance manuals suggest that you drain a water heater at intervals ranging from six to 12 months. The reason this is recommended is to help remove any sediment or buildup that collects on the bottom of the water heater tank due to minerals and other particles in the water. This buildup will cause the water heater to work harder to heat the water, using more energy and costing more money to run.

Before You Begin

Before getting started, make sure you know where your home’s main water shutoff valve is located. While you won’t necessarily need it during this process, it’s always a good idea when working with any kind of plumbing fixtures in your home to be acquainted with this valve in case something goes wrong and you need to stop all water flowing through your pipes.

Safety Considerations

This process involves working with water that can be extremely hot. You might want to turn off your hot water heater several hours before you begin in order to let the water in the tank cool off. If you’re not able to do that, then use heavy-duty rubber work gloves to protect your hands from any splashes and use safety glasses to keep your eyes safe from hot water droplets.

How to flush a water heater

Water heaters can lose their efficiency resulting in higher heating cost and higher water bills. The reason for them losing efficiency is sediment in the tank building up which is impeding heat transfer and absorbing some heat as well. This sediment can also cause damage to your water heater or cause clogs in your water lines. The answer to this problem is a simple flushing of your water heater. It’s typically recommended to have this done once a year.

Caution: A professional should be called to perform maintenance and inspect the health of your water heater, if you are not comfortable in such tasks or have an older water heater that might not have obvious signs of damage. Check with your manufacturer’s warranty regarding maintenance to ensure you won’t void your warranty performing the maintenance yourself. Before performing the maintenance below, know where your main water shut off valve is and it’s in working order in the event something goes wrong to prevent further damage due to water damage.

Steps to flush the water heater

Turn off or turn down the heater’s heating system or gas to prevent the water heater from turning on and heating an empty tank. If you have a gas water heater this could be setting the thermostat to off or “pilot” or “vacation mode” and in the case of an old system, it may require turning off the gas to the water heater. You may have to relight the pilot light on older gas water heaters if the gas is turned off, and you should know how to relight it and where it is located. If it’s an electric water heater, you can turn if off via a switch or unplug it or you may have to turn it off via the circuit breaker if there isn’t a way to turn off the flow of electricity to the water heater.

Turn off the water source to the water heater. In some homes this means the main water valve to the home, others may have a shutoff valve near the water heater. You may have a filter or system such as water softener that may have a shut off valve available.

Connect a garden hose to the tank’s drain spigot near the bottom of the tank and remember not to overtighten. Place the other end of the hose to an area that can handle the amount of water and the heat from currently hot water in the water heater tank.

Note: If you don’t want to worry about draining hot water from the tank, turn off only the heating source and leave the water valve on and turn on a hot water faucet in your home to allow the hot water to drain from the tank down the sink drain and water heater’s water will be replaced by cold water. After you have found the water temperature is cool enough, turn off the water source to the heater as the previous step.

Turn on at least one hot water faucet in your home to allow air to flow to prevent a vacuum from forming and not allowing the water to drain from the hot water tank. Open the drain valve to allow the tank to empty through the hose. Check with your manual as to how to open the drain valve as it can vary depending on model. Listen for the sound of water running, if you don’t hear water and don’t see any draining at the end of the hose, you may have something preventing the air from flowing such as a backflow preventer or sediment has clogged the drain and you will need to open the pressure release valve to allow air into the system. This is also an opportunity to test your pressure valve as suggested below. Most When you are sure water is coming out, check the hose to ensure there isn’t a leak along the way and the other end is still draining in the spot you have chosen and the water draining isn’t going to overflow the draining area.

Once the water is draining, observe the water’s color and clarity. You want the water to be fully clear or mostly clear at the end of the draining. The next thing is to ensure the remaining sediment on the bottom of the tank gets flushed through by turning on the water valve to the tank to allow water to rush into the tank with the drain valve open. Sometimes it helps to turn on the water for about 15 seconds and turn off the water and wait for a few minutes and do this again a few times to completely remove some sediment that is stuck on the inside. Observe the water draining to be sure the sediment is gone, and the water being drained is clear. Turn off the water to the tank when you are finished flushing the system.

Now that the system is cleaned out, it’s time to put everything back:

  • Close the drain valve and remove the hose.
  • Close the pressure valve (if you opened it, if not still check that it is closed).
  • Turn the water back on to the water heater.
  • Open the hot water faucets around the house to ensure the water flows and there is no air trapped. You may see sediment coming from the faucets, just wait until the water is clear. Once it is clear, turn off the faucet.
  • Turn on the heating source, which may involve reignited the pilot light if it’s a gas water heater and it blew out.Be sure to turn it on only after the tank is full. Turning on an electric water heater without the tank full will cause the heating element to burn out.

You may want to make a note somewhere of the date you performed this service or had this service done so you can keep a maintenance record for yourself and possibly your insurance. This will help remind yourself when it was done last year and if there are some issues with your water heater before a year is up, there may be more serious issues with your water lines or water heater that a professional should look at before it becomes an expensive repair with water damage also involved.

How to flush a water heater

Your water heater sits quietly in the corner and you don’t give it a second thought – UNTIL it stops working! Yet, just 10 minutes of your time can keep your water heater from quitting on you.

For any appliance to work efficiently and last a long time, some maintenance is essential. When it comes to your water heater, that means flushing it.

Why should I flush my water heater?

Sand, debris and naturally occurring minerals settle to the bottom of your water heater. Over time, this layer of sediment can significantly build up. Regularly flushing your water heater will keep the sediment from building up, so your water heater can run efficiently and have a long life.

What happens if I don’t flush the water heater?

Inside the unit, water comes in contact with a heating element and presto – you get hot water. But if you put a solid layer of something between the heating element and water (like sediment) this can cause the water heater to not run efficiently or last as long as it should.

This is because the sediment slows down the transfer of heat so the heat begins to build up under the sediment. Then the bottom of the water tank overheats. This overheating causes damage to the wall lining that prevents the tank from rusting.

As a result, problems can range from minor to major!

On the minor end of the scale, there might be a small leak around the valve. Another minor issue might be that the heating element burns out and you have to take a cold shower. Inconvenient, but not catastrophic.

On the major end, worst case scenario, the tank rusts completely through causing the water heater to rupture. The leak – it’s not like a broken bucket with a set amount of water. The fact is, there will be a constant supply of water from the city continuing to feed the water heater. It will leak constantly until the water is shut off. If undetected for several hours, or worse because you’re away for a few days, your home or office could suffer from some serious water damage.

What should I do if my water heater ruptures?

There are a few things you’ll want to do immediately.

  • Stop the water supply to the tank. To do this, find the valve located near where the water supply line meets the tank. Turn the valve to the OFF position.
  • Turn off the power to the tank. To do this, go to the electrical box and find the breaker for the water tank. Flip it and ensure it is off. NOTE: Skip this step if there is standing water near the electric box – safety first. .
  • Depending on how bad the water damage is to the surrounding area, you may want to contact your insurance company.

What are the symptoms of sediment build up?

The most common symptoms of sediment build up are:

  • There is no hot water.
  • It takes a long time to get hot water.
  • You see flakes coming out of the tub spout (usually the first place to see flakes).
  • Water temperature fluctuation.
  • Rusty colored hot water coming from faucets.
  • Your hot water smells foul (sediment is a breeding ground for bacteria).
  • Water leaks around the drain valve, or worse from the tank itself.
  • Your energy bills are higher than normal.
  • The water temperature directly from the faucet is lower than the temperature set on the tank. (Note: To measure the temperature of water coming from your faucet, hold a kitchen thermometer under the running water.)
  • Odd noises coming from the water heater. (As heat builds under the sediment, a small amount of water turns into steam. The steam bubbles collapse making noises ranging from annoying to frightening.)

How often should the water heater be flushed?

It’s best to flush your water heater before you start seeing or hearing symptoms. As a rule of thumb, water heater manufactures recommend flushing the unit annually. Robert, master plumber with Trinity Plumbing, recommends, “Flush your water heater no less than once every year. This will help prolong the lifespan of the water heater.”

Do tankless water heaters need to be flushed?

It is most important to keep the heat exchanger clean and free of scale build up so it can function properly. A tankless water heater unit will shut off and not serve you hot water if it is not serviced routinely.

Can I flush my own water heater?

A standard tank water heater is fairly simple to flush. A tankless water heater, not so much. A tankless requires a little more knowledge, so Trinity Plumbing would not recommend someone flushing a tankless themselves.

No matter what type of water heater you have, you may want to consider hiring a plumber to do the annual maintenance. Not only will they take care of the water heater, they will clean slow drains, repair leaks, and other tasks to keep your plumbing system working smoothly.

Any DIY tips for flushing a water heater?

  • For your particular water heater, always read and follow all manufacturer’s directions and warnings before flushing.
  • Make sure you use a hot water rated water hose, so it won’t collapse when you have hot water running through it.
  • You do not want to put the flushed hot water on the grass, plants or bushes because it will kill the roots. Instead let it run down the driveway so it can cool down before getting into any landscaping.

How long does it take to flush a water heater?

On average, it takes 10-20 minutes to flush a water heater. Continue until water runs clear without any sediment. If flushing is done from the first year after water heater is installed and continued throughout, you may never see any sediment coming out of garden hose because you are not allowing it to build up.

Should I flush an old water heater?

“If a water heater is getting up there in age, I would not recommend flushing it if it has never been flushed previously,” warns Robert. The sediment may have already started corroding the water heater. There is a high risk of causing damage to the valve and/or heater. For example, when you open the drain valve, you might not be able to close it because the thick sediment will most likely will clog the drain.

When is the best time to flush a water heater?

It is common for most towns to flush their fire hydrants at least once a year. This helps keep hydrants clear of debris, but the sediment that is disturbed could end up at the bottom of your water heater. Find out when your fire department is flushing fire hydrants. Wait a few days and then flush your water heater.

After your water heater is flushed, immediately put it on the calendar to do it again next time.

If it’s so easy, why do more people not flush their water heaters?

Like most of us, out of sight is out of mind. If you don’t feel confident flushing your water heater, contact Trinity Plumbing and our team of expert plumbers will have your water heater feeling as good as new.

How to flush a water heater

Did you know that many homes in Omaha, Nebraska have water with an average hardness of 10 grains per gallon? This means that the water contains high concentrations of calcium carbonate (CaCO3). CaCO3, in turn, is a key component of limescale, the hard, chalky deposit that builds up in water heater tanks.

Per the US Department of Interior and the Water Quality Association, 10 gpg is hard water. Hard water may not be a health threat, but it can reduce your water heater’s efficiency and service life.

Learning how to flush out a water heater the right way can help you keep it in tip-shop shape. We outline the basic steps on how to clean a water heater in this guide, so be sure to read on!

Determine the Last Time You Flushed Your Tank

Most water heaters have a service life of eight to 12 years. However, this still depends on regular maintenance, including flushing it twice a year. If you haven’t drained yours in a long time, hold off on doing so, as it could trigger tank leaks.

That might happen if the tank has interior fissures now covered with limescale. Flushing your tank could remove some of those mineral deposits and expose the cracks. If this occurs, your tank could start leaking water from the bottom.

In that case, it may be best to call a plumber instead of flushing the tank yourself. A licensed plumbing expert has the eyes and the tools to discern potential leaks.

Turn Off the Water Heater’s Power Supply

If your heater is only about one year old, you can go ahead and flush it. Before you do so, switch off the gas or electrical power that supplies energy to your tank. This is for safety purposes, as it can help prevent accidental gas leaks or shock injuries.

Do note that in the US alone, some 30,000 non-fatal shock injuries take place each year.

If you have a gas-powered heater, simply switch the control to “Pilot” mode. If you have an electric heater, you can cut its power supply by switching off its circuit breaker. You can find this breaker in your main electrical panel.

It’s also a smart idea to wear rubber insulating gloves and anti-slip footwear. A face mask and goggles can also protect you from the dust and debris that you’re likely to stir up as you clean the tank.

Close the Cold Water Valve

Many water heaters have color-coded valves to distinguish hot from cold inlets. If yours is color-coded, the cold water valve should have a blue handle.

If your heater’s valves aren’t color-coded, take a closer look at the valves themselves. They should have a label or mark that indicates whether they’re for the hot or the cold water supply.

Let Your Tank’s Contents Cool Down

More than 450,000 burn injuries requiring medical treatment occur in the US each year. Many of these injuries take place within homes.

Now, since you’re flushing the water heater tank itself, you want to be extra careful. It’s best to wait for a few hours to let the water inside the tank cool down before you drain it. Doing so can help reduce your odds of scalding yourself.

If you can’t wait that long, consider booking a quick water heater service request. This way, you can have a licensed plumber come to your aid right away and perform the heater maintenance for you.

Connect a Hose to the Tank’s Drain Valve

Near the very bottom of your water heater tank is a drain valve either made of plastic, composite, or brass. You can connect one end of a hose (a garden hose would do) to this valve after waiting for a few hours for the water to cool down. Run the other end to a floor drain, or if it’s long enough, outside of your home.

The most important thing is to make sure the open end sits at a lower level than the one connected to your tank. This helps ensure that gravity can do its work, which is to push the water from inside the tank to the other end of the hose.

Let It Drain

At the top of your heater is another valve called the temperature and pressure (T&P) relief valve. It’s a safety component that opens and releases excess heat and pressure from within the tank.

Open the T&P valve, plus another hot water faucet in the house, to enable air to enter the tank. Next, open the drain valve itself. The air will work hand in hand with gravity to push the water inside the tank out of the drain valve.

Give your heater several minutes so that it can empty its contents. Monitor the last bit of water that drains, too, as it may still contain sediments. If so, open the cold water supply valve to let a couple more gallons of water run through the tank.

Refill the Tank

Once the water that leaves the tank is clear, close the T&P valve, drain valve, and hot water tap you opened. Remove the hose you attached to the drain valve. Wipe any areas that may have gotten wet while you were flushing the tank.

Next, open the cold water supply valve so you can start refilling the water heater tank. Allow the water to flow for about 15 minutes before you run a nearby hot water tap. Doing so can help release any remaining air from within the tank and the plumbing pipes.

You can expect the water coming out of the hot water faucet to be full of air bubbles. As soon as this clears, close the tap and restart your water heater.

Follow These Expert Tips on How To Flush Out a Water Heater Today

As you can see, there are several steps to take in order to flush out a water heater the right way. If you’re not confident of your DIY skills, it’s best to leave this task in the hands of the pros.

If you’re in Omaha, NE, or nearby, you can put your trust in our team of plumbing professionals here at Eyman. Get in touch with us today at (402) 731-2727 so that we can help you flush and service your water heater.

Remove scale deposits from the water heater tank regularly to ensure optimum performance.

How to flush a water heaterDid you know most water heater manufacturers recommend flushing the tank to remove silt, sediment, and mineral scale buildup once per month? The vast majority of property owners do not flush their tanks this frequently, and some skip this vital maintenance step altogether. Don’t follow their example! Instead, invest in regular hot water heater flushes and reap the following 5 benefits.

Reduce Noise

Often, when water heaters start making popping, crackling, or banging sounds, the culprit is scale buildup. Don’t be fooled if the noises suddenly seem to go away on their own—what has happened is the layer of scale inside the tank has solidified so much that water can no longer percolate through it easily. Your best move is to flush and descale your water heater as soon as it becomes noisy.

Improve Heating Speed

The more foreign material has settled on the bottom of the water heater tank and/or built up on the electrodes of an electric water heater, the more difficult the heat transfer process becomes. In other words, it takes more time to heat water to the desired temperature. This can cause problems with running out of hot water. Fortunately, you can get your water heater back up to speed with a simple water heater flush.

Reduce Operational Costs

The tougher it is for the heating element to transfer heat to the water, the more energy will have to be consumed to heat your water. This means higher utility bills. You may also end up spending more on repairs as various parts fall victim to corrosive scale deposits or clogging sediments. Flushing your hot water tank can help cut costs significantly.

Extend Equipment Life

Scale buildup contributes to early water heater failure in two ways. First, in an electric water heater, the scale can cause the electrodes to fail prematurely, in which case you won’t have any hot water. In a gas water heater, scale buildup turns into a kind of insulating layer between the heat source and the water. This means the metal in the bottom of the tank gets hotter than it should, and may eventually become so stressed that the tank leaks or fails. Compared to the high cost of water heater replacement, routine flushes are a bargain.

Ensure Warranty Protection

One final benefit of flushing your water heater regularly is that it may help ensure the manufacturer honors the warranty if the tank should fail. Most warranties do not protect against scale failure, so you need to have proof that this cause can be ruled out if your tank fails for some other reason and you want coverage.

How Often Should You Flush Your Water Heater?

The frequency at which scale builds up in your water heater varies according to how high the mineral content of the incoming water is, how hot you keep your water, and how much water you use. This means it is very hard to make sweeping generalizations about how often to flush and descale your hot water heater. Your best bet is to contact the pros at The Stanley Louis Company for help. We can show you how to monitor the buildup in your water heater and provide complete water heater flushing and scale removal services as needed.

How to flush a water heater

Your water heater needs regular maintenance as does other machines such as your car. Over time, water heaters collect things such as sediment, calcium, and minerals that settles at the bottom of the tank. The heating element of a water heater is at the bottom of the tank. If this heat is being blocked by sediment and other materials, then your water heater has to work harder to heat the water.

There are really no downsides to flushing a water heater. Sediment build up causes damage and it is more expensive to leave it than to just flush it out regularly.

How Often Should I get My Water Heater Flushed?

It is recommended that you flush your water heater at least once per year. Doing so will help to prevent the potential problems that sediment can bring over time.

What Happens if I don’t Flush My Water Heater?

Leaving sediment build up in your water heater can not only cause it to work harder, but also lead to some serious problems. For example, if the sediment gets to be too much, you can start to see it come out of your faucets.

Over the long term, sediment can cause even more serious issues. Things such as pipe bursting, loss of water pressure, or even the break-down of the tank itself. These problems tend to occur after the course of two to five years.

Do I Need to Flush a Tankless Water Heater?

Yes. Even though tankless water heaters don’t hold as much water as traditional tanks, they can still build up sediment and require cleaning and maintenance.

How do I Flush My Water Heater?

  1. Turn off gas if you have a gas water heater or electricity if you have an electrical one.
  2. Allow the water heater to cool down for a while
  3. Shut off water supply
  4. Turn on the hot water from a nearby faucet to prevent a vacuum from forming and allowing the tank to drain easier.
  5. Attach a hose to the drain valve and run the hose to a drain or empty bucket
  6. Drain the water heater tank by opening the drain valve and allow the water to flow until it stops, you may have to empty a bucket several times during this process. The water can be very hot at this stage unless you let the water heater sufficiently cool down, be careful!
  7. Flush the tank by reopening the cold water supply and allow this to drain. Do this a couple of times to rid of all of the sediment.
  8. Close the drain valve
  9. Fill the water heater tank by reopening the water supply valve
  10. Power up the water heater

Draining a water heater is doable at home, but can also be dangerous. If you are uncomfortable with flushing your water heater yourself or want to make sure it is done right, call a professional technician to have your water heater flushed in no time.

The often overlooked hot water heater, that big tank that’s shunned and hidden in a utility closet somewhere in your home, rarely gets any attention. Most of us don’t pay it any mind until we’re in the shower, complaining about the lack of hot water, or the five minutes it takes to heat up before we can even get in the shower. Then, all of a sudden, the water heater is a concern.

Now that’s not fair is it? You didn’t even peek in on the ‘ol water heater once in the last year and now you want to scream obscenities at it when you don’t get the hot water you so desperately want? That’s not very nice of you. But, we understand the frustration. We’ve been there, and we can help!

Your water heater, like most everything mechanical in your home, needs routine maintenance to keep it operating at its best. One often neglected task is flushing your tank to get rid of the sediment that builds up inside. Allowing this sediment to build up hampers the heater’s ability to do its job efficiently, shortens the life of your water heater, and costs you more money and more headaches in the future.

So, when should you flush your water heater?

If you’re asking that question, chances are right now would be a good time to get it flushed out. Water heaters typically need to be flushed once a year to keep them performing at peak efficiency. For some, the need may be more often, depending on the hardness level of their water. Homes with higher levels of mineral deposits in their water may need to flush the heater on a more routine schedule. There are also some guidelines to follow depending on the amount of people in your home, which obviously increases your water heater’s workload. Here’s a general rule of thumb:

One or two people in a home: Inspect the water heater every six months and drain it every 12 months

Three to five people in a home: Inspect the water heater every four months and drain it every eight months

Six or more people in a home: Inspect the water heater every four months and drain it every six months

There are also some signs that you can keep an eye out for that can alert you to the need to get it flushed. If you’re noticing any of these, it’s worth the effort to do a flush or call in a professional.

Action Mechanical is offering a special on water heater flushes and maintenance checks for just $50 through January 31, 2020!

  • Increased Heating Time: Is it taking longer for your faucets and shower to push out hot water? Your problem may be mineral deposits and scale build up in your tank. When you have sediment build up, it settles into the bottom of the tank, making the heating element work harder because it’s also heating the sediment.
  • Noisy Heater: If there’s too much sediment, as mentioned above, the heater works overtime to heat your water. The water that’s beneath all that sediment can oftentimes boil and cause the sediment to rattle around inside the tank. So give a listen to your heater occasionally.
  • Decrease in Water Pressure: Hard water deposits can narrow or block the pipes leading away from your water heater and cause a decrease in water pressure.
  • Deposits in Your Water: If left un-checked for too long, your tank can build up so much sediment, that you’ll see it come out of the faucet, into the glass you drink from or the pot you use for cooking.

I’ve never flushed my tank, where do I start?

It’s recommended that your first step in the flushing process is to pick up the phone, call Action Mechanical, and let our professional plumbers come tackle the job, while you pour yourself a coffee and relax with a good book. But for the sake of educating you for all future flushes, we have a 9-step guide to tackle the task on your own.

  • Step 1: Turn off the cold water supply to your water heater. If you have an older home, this may require turning off the main water supply where it enters your house. If you have a water softener unit, there should also be a shut-off valve there as well.
  • Step 2: You want to avoid having your heater turn on once the water is drained, so turn off the water heater thermostat. If you have a natural gas heater, you’ll also need to close the gas supply valve.
  • Step 3: Connect a garden hose to the tanks drain valve, generally located at the bottom of the tank. The other end of the hose should either flow into a floor drain, or be led outside, away from your home’s foundation and any landscape.
  • Step 4: Open up all the hot water faucets in your home. This will speed up the draining process.
  • Step 5: Open the tanks drain valve and let the draining begin. If water does not begin to flow out of the hose, you may have a blockage from the sediment. In this case, you’ll need to open the temperature pressure release to let off pressure from the tank and drain any water that’s left in the hot water pipes downstream from the heater. Use a wet/dry vacuum to suck out some of the blockage until the water starts to flow.
  • Step 6: Once your tank has drained, turn the cold water supply back on and let it run for a few minutes to help rinse out any sediment left in the tank. Continue this until you’re sure there’s no more sediment coming out. If needed, let it drain into a glass and see if any sediment settles to the bottom. When you’ve gotten the last bit out, turn the water supply back off.
  • Step 7: Disconnect the hose, and use a wet/dry vacuum to suck out any sediment from the valve opening. This will ensure a proper seal, and prevent the valve from leaking. After closing the valve, turn the cold water supply back on.
  • Step 8: Go check the hot water faucets that you have open and make sure water begins to flow out. Don’t be alarmed if you see rust or sediment coming out at first, it may take a minute to run clear. Once it runs clear, you can shut them off.
  • Step 9: Reset your water heater thermostat to your preferred setting. If you have a gas heater, reopen the gas supply valve and relight the pilot (follow your manufacturer’s instructions). Once your tank has filled, you should have hot water back up and running within about twenty minutes, depending on heater size, efficiency, and whether it’s gas or electric.

Take advantage of our $50 water heater service special, now through the end of January 2020! Service includes thorough maintenance inspection and tank flushing!

So there you have it, folks! Water heater flushing 101 is a wrap. In the future, remember to check your water heater periodically to ensure it’s giving you the efficiency you need to keep hot water flowing through your home all year, at the most cost effective levels possible.

When in doubt, you can rely on the trusted professionals at Action Mechanical to fix or diagnose any of your plumbing problems, day or night. Our certified technicians are on call 24/7, and will work to get the job done right the first time, every time.

Your water heater is what provides all the essential hot water to your house when you need it. The times you realize how important it truly is can often be when it isn’t working or is backed up. To make sure your water heater is working properly, you have to make sure to flush it out to ensure it works at its best capacity.

To help you understand the basics of water heater flushing, we will first look at why it is so important and how often you should go about doing it. We will then walk you through a general guideline for flushing your own water heater so it can perform efficiently.

Why Do You Need to Do a Hot Water Heater Flush?

With extended use, water heaters begin to accumulate sediment and buildup that is naturally found in the water supply. What happens in the heater is that sediment can buildup and clump together causing either inefficiency or damage to the unit. This is especially common with water heaters in Phoenix, which has very sediment-rich water.

Flushing out your heater prevents excessive sediment buildup and ensures that you are able to operate the unit with better efficiency and less worry of failure. It is possible that some of the most common water heater problems you are experiencing could be resolved by a simple flush.

Water Heater Flush Cost

As you’ll see, a water heater flush costs nothing considering you can do it yourself with just a few easy steps.

How Frequently Should You Do a Hot Water Heater Flush?

Considering how essential your water heater is, you shouldn’t put off flushing out your system for too long. Every water heater has a different lifespan but making sure you do regular water heater cleanouts will help it reach its intended lifespan. On average, you should look to flush your heater every few years. If you want to ensure the best performance for your unit, flushing it once a year would be ideal and these next steps will show you how easy that can be.

Steps for Performing a Water Heater Cleanout/Flush

Shut Off Gas

Just like any other appliance in your home, your heater will have some power being supplied to it for operation. Depending on your unit, you may have to do just one of these steps during a water heater flush or possibly more. Shutting off your gas will ensure that the unit is not receiving any gas and can’t heat up or leak.

Cutting off the power to your unit can usually be done through your circuit breaker where you should have a labeled switch for the heater. This will prevent any electrical issues from happening as you work on the unit. Remembering this step will ensure a safe working environment for whoever is completing the flush.

Open a Hot Water Faucet

You need to trick your system into thinking it needs to be running, so you must open a hot water faucet in your house to do this. Water will pour out, but it will not be heater at the time of the procedure. This step is also very important as it prevents a vacuum from forming in the pipework that could cause unwanted air bubbles in your water system.

Turn Off the Cold Water Valve

Your water heater will have a supply valve that leads into the unit for supplying cold water. When performing the flush, you will want to shut this valve off. It should be located either on or near your unit and will generally be towards the top. It will look like a standard faucet valve and could potentially be colored blue to represent cold water. Turning this valve off prevents water from flowing into the unit during the flush which would make the whole process a lot messier.

Connect a Hose to the Heater

The next step is to locate your spigot. This will be at the bottom of the unit and will look like a normal hose faucet. You may want to place a bucket under this before starting anything else as it could start to drip as soon as the cap is removed. You need to find a garden hose that can screw onto this spigot as that is the easiest way to drain the system.

If your heater is higher up in your house, gravity should be able to let the water flow. If the unit is in your basement, a pump may be needed to help the water get out of the unit. Make sure you have the end of the hose placed in some sort of bucket or containment area, so it does not spill everywhere.

Water Heater Flush for Sediment: Drain the Tank

At this time, you can begin to drain the unit by turning the spigot that the hose is connected to. As the water drains out of the tank, you can use this time to see the conditions that your heater may be experiencing. If the water is mostly clear and normal looking, your water heater is probably in good shape.

However, water that is darker and that contains sediment could be a much bigger issue. If you are emptying the tank and there is a significant amount of solid material coming out, the inside of the tank could be much worse than you’ll be able to solve with a simple water heater flush for sediment. This is where you will likely want to call a professional to inspect the tank for more serious issues and buildup.

Note: If you’re doing tankless electric water heater flush, you’ll obviously be skipping this step.

Flush the System

Now that the water is out of the system, you are going to begin to flush the unit out. Remember the cold-water spigot you previously turned off? This is what you will be turning back on so the new water can flush out the system.

It is advised to empty out the old bucket and check for sediment before filling it up with this new flushed water. Flush your water tank for a few minutes until the water coming out appears to be clear and normal. This will indicate that the system is fully flushed, and the process is almost done. Remember to turn off the cold-water supply before taking off the hose and removing the bucket.

Reactivate Power and Gas

Now that the flush is done, it is time for clean-up. The first thing to do is to turn off the drain that the hose was connected to so that water cannot escape. Also, remember to close the hot water faucet in your home that you opened at the beginning.

Turn on the cold-water supply again and allow the tank to fill back up. You will want to open the pressure valve on your tank when it is full so the air can escape, and the unit can operate. Open the hot water faucet in your house again to let any excess air out. Lastly, turn back on the gas and water leading to the tank. Give the water roughly 30 minutes to heat up before testing to see if the water coming out of your house is hot when needed.


Congratulations! You have now completed all the essential steps to flushing your water heater in a relatively quick time. Now that you understand the process, you can be better prepared for the next time your heater needs a flush. Taking the time to flush your heater will ensure that it is operating at its highest potential and serves you well for many years.

Frequently Asked Questions

How often should you flush a water heater?

Flushing your water heater at least once per year is ideal, particularly if you live in a region with hard water and don’t have a softener. If you do have a functioning softener, you can get away with flushing once every couple of years but doing it more frequently isn’t going to hurt.

How much does it cost to flush a water heater?

If you’re not confident doing the job yourself, expect to pay around $100. This is really a minimal expense considering how damaging sediment can be for your water heater.

What happens if you don’t flush your water heater?

If you neglect flushing your water heater, sediment may cause damage to the tank and issues such as clogged drain lines.

How long does it take to flush a water heater?

While your first flush might take a bit longer, you’ll eventually be able to do the whole process within about an hour.

Extend your water heater’s life span by draining the tank annually to remove any sediment that may have built up.

Related To:

Most water heaters employ a large, insulated holding tank to ensure there’s plenty of hot water on hand at all times for different purposes throughout the home. Over time, naturally occurring minerals in the water, as well as sand and grit flushed from municipal water lines, can settle in the bottom of the tank. This sediment buildup can potentially reduce the efficiency and capacity of your water heater. It can also plug the drain and interfere with ongoing maintenance, leading to early failure. Draining a water heater to remove sediments is an easy DIY that takes very little time and just a few basic tools.

How to flush a water heater

Hot-Water Heater

Over time, naturally occurring minerals in water, as well as sand and grit flushed from municipal water lines, can settle in the bottom of your home water heater tank. Sediment buildup can potentially reduce the efficiency and capacity of your water heater.

Photo by: Sherri James

Over time, naturally occurring minerals in water, as well as sand and grit flushed from municipal water lines, can settle in the bottom of your home water heater tank. Sediment buildup can potentially reduce the efficiency and capacity of your water heater.

Sediment can interfere with burner efficiency in a gas water heater and can cause cracking and popping noises during heating cycles. Depending on your water source and the mineral content, both gas and electric water heaters should be flushed of sediment every one to two years to ensure optimal performance.

Dave Moody, a plumbing pro with Service Experts, suggests, "You may need to drain your water heater more frequently if your water source is a well or if your municipal water has higher-than-normal sediment content."