Ask a Plumber Blog: Guidance from a Master Plumber

It’s Not Just The Toilet That Needs a Good Flush – Flush Your Water Heater!

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Water Heater – I work hard. I do a great job. But everybody just ignores me. Providing hot water is such a thankless job.

You – What’s on TV?

Water Heater – I was once shiny and new. Now I’m a dust collector.

You – Check out this Facebook post!

Water Heater – My insides are sludge. I am having a hard time. I’m thinking about quitting.

You – Why is it taking soooo long to get hot water?!

Water Heater – I can’t take it anymore. I quit.

You – “Nooooooo. NOT the 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.
  • Contact an emergency plumber.
  • 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.

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Robert (Master Plumber)

Robert (Master Plumber)

Owner of Trinity Plumbing, LLC
Residential & Commercial Plumbing

Serving: Acworth, Dallas, Kennesaw, Marietta, Smyrna, & surrounding Metro Atlanta areas

Full Bio & All Author Posts
Robert (Master Plumber)

Robert (Master Plumber)

Owner of Trinity Plumbing, LLC
Residential & Commercial Plumbing

Serving: Acworth, Dallas, Kennesaw, Marietta, Smyrna, & surrounding Metro Atlanta areas

Full Bio & All Author Posts