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To Flush or Not To Flush a Water Heater

  • Alma 

Water heaters are responsible, for supplying water to our homes. They accomplish this by utilizing either gas or electricity to heat up a reservoir of water, which is then readily available for use. As time passes, minerals build up and settle as sediment at the base of the tank.

This is where the great water heater debate starts. Some will tell you a water heater needs to be flushed out regularly. However, is it even necessary or beneficial? Can flushing a water heater actually be ruining your water heater? Let’s find out.

newly installed water heater

The Great Water Heater Controversy

Those who advocate for annually flushing a water heater emphasize that sediment buildup in the tank reduces efficiency, shortens lifespan, and can clog valves. Regular flushing supposedly removes this sediment, improving performance and longevity. This viewpoint is supported by some manufacturers, companies that make tools for flushing, and even some plumbers.

The other side of the debate questions the need for routine flushing. Modern water heaters are better designed and less prone to sediment buildup. Additionally, they say flushing can introduce air into the tank, which can lead to corrosion and, therefore, reduce efficiency. It can also stir up the sediment, potentially clogging pipes and fixtures. This viewpoint is supported by some water heater manufacturers, plumbing professionals, and independent studies.

Should I Flush my Water Heater?


Flushing water heaters, especially incorrectly, can lead to damage to the tank, pipes, valves, or fixtures. Incorrectly flushing a water heater may result in cracks, leaks, or bursts. Additionally, flushing water heaters can potentially dislodge the anode rod. Damage to the anode rod can cause rust and corrosion to begin prematurely in the tank. Flushing water heaters is potentially way more harmful and there isn’t enough evidence to even show doing so is necessary or effective. We would recommend to refrain from flushing water heaters.

When you should Flush it:

  • Buying used: If you’re buying a used water heater, definitely flush it before installation. Just remember the lifespan of a tank-style water heater is 8-12 years.
  • Tankless Water Heaters: Tankless water heaters require flushing once every 1-2 years. Consult with a proffessional before attempting to do yourself.
  • Warranty requirements: While rare, some warranties might require the water heater to be flushed by a professional plumber to stay valid.  Always check your warranty and consult the manufacturer if unsure.

Definitely DO NOT Flush it:

  • Air introduction: Draining and refilling the tank can introduce air, leading to corrosion.
  • Sediment gets released: Flushing stirs up and releases accumulated sediment, potentially clogging pipes throughout the home or building.
  • Damage to older water heaters: Forcing out sediment in older tanks can trigger leaks or failure.
  • Efficiency: Modern water heaters are designed to resist sediment buildup, making routine flushing unnecessary.

Misconceptions about Flushing Water Heaters

sThere are myths surrounding the flushing of water heaters that need to be debunked. Some of these misconceptions were possibly started by plumbers who wanted to charge for an additional service that is unnecessary and potentially damaging, ensuring the customer needs a new water heater sooner rather than later.

Myth #1, water heaters should be flushed annually: It is unnecessary to flush water heaters, especially modern models. Many newer units are specifically designed to resist sediment buildup.

Myth #2, flushing removes all sediment and rust: Flushing does remove some sediment and rust, but it doesn’t eliminate all of it. In fact, it can potentially stir up existing buildup, leading to clogs in your pipes and fixtures and causing air pockets in the sediment, which causes more rust and corrosion.

Myth #3, flushing extends the life of the water heater.  While flushing might help clean out the sediment. There’s no evidence that it extends the life of the water heater. In fact, excessive flushing could cause damage, shortening the lifespan.

Myth #4, flushing fixes water heater issues: Flushing does not solve issues. Instead, proper diagnosis and targeted repairs are much more reliable fixes than flushing as a solution.

Water Heater Maintenance With Sunset Plumbing

Here at Sunset Plumbing do not recommend flushing your water heater. However, there are other water heater maintenance items we highly recommend. If you’d rather a professional plumber do maintenance and plumbing repairs for you, we’ll gladly send someone your way to take a look. Here’s a little more about us… 

  • 24/7 Emergency Services: We are available at any time or night to take care of any emergency situations.
  • Customized Solutions: We provide unique solutions to suit your specific needs.
  • Professional Installations & Repairs: We are highly skilled plumbing professionals licensed and bonded in the state of Utah.

Flushing your water heater is not a solution. It comes with potential risks, such as introducing air or releasing sediment. In some cases, alternative maintenance methods, like draining a few gallons and checking the anode rod, can be sufficient.

It is crucial to consult a plumber who’s familiar with your specific water heater and water quality. This will help you make informed decisions regarding its maintenance.

Flushing your hot water system requires skill and knowledge. You can choose what is best for your system’s health and lifespan by understanding the process.

plumber working on water heater
enjoying hot water

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Alma Bradshaw

About The Author

Hello, My name is Alma Bradshaw. I'm a licensed plumber with over 20 years of experience in the industry. It's important to stay informed and up-to-date on the latest plumbing techniques, innovations, codes, and regulations. Learn more about plumbing here and feel free to comment below with any questions.

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Sunset Plumbing Utah

1562 Evans St, Lehi, UT 84043

Sunset Plumbing

776 N 470 E Genola, UT 84655

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Sunset Plumbing Utah

1562 Evans St, Lehi, UT 84043

Sunset Plumbing

776 N 470 E Genola, UT 84655

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