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Why Is My Water Heater Making a Knocking Sound?

Why Is My Water Heater Making a Knocking Sound?

A water heater is a fundamental household appliance that provides the hot water you need to cook, shower, and clean with. While it’s normal for a hot water heater to make a slight knocking sound due to the natural expansion and contraction of the metal tank during the heating process, excessive knocking likely results from a bigger problem such as loose parts, corrosion, or sediment buildup.

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How To Eliminate the Knocking Noise in Your Water Heater

Here Are a Few Ways to Eliminate the Knocking Noise:

  • Replace the anode rod: This is a metal rod that protects the tank from corrosion and rusting. All you have to do when the anode rod stops working is remove the old one and install a new one.
  • Replace the gas valve: The gas valve controls the temperature of your hot water heater and allows you to turn it on and off. If this part malfunctions, the tank’s internal temperature will get too high and can cause a knocking sound. To fix the problem, simply remove the current valve and replace it with a new one.
  • Tighten the rubber diaphragm: This part can start vibrating against the metal tank and cause a knocking sound. Using a wrench to tighten the diaphragm will stop the knocking.

How To Flush Your Hot Water Heater

If your tank has a sediment buildup problem, you’ll need to flush it out. This process drains the dirty water and refills the tank with fresh water. Here’s how to do it:

  • Open the cold-water valve at the bottom of the tank to drain the dirty water.
  • Once all the water has drained, close the valve and open the hot-water faucet to let air bubbles escape.
  • Open the cold-water faucet for fresh water to fill the tank.

What If the Knocking Sound Continues After Flushing the Tank?

If the knocking sound continues after you flush the tank, your hot water heater likely has a bigger problem than sediment buildup. One of these three things might be the culprit:

  • Faulty gas valve or pilot light
  • Faulty thermocouple or thermostat
  • Low water pressure

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Ways To Increase the Life Of Your Hot Water Heater

If you want your hot water heater to last for years to come, complete these three simple maintenance steps:

Check the Pressure Release Valve

As the temperature increases in your system, the water heater pressure relief valve allows excess pressure to escape to prevent overheating and damage. Checking this part regularly is essential to a properly functioning, long-lasting water heater.

Flush the Tank

Flushing your hot water heater’s tank regularly will remove sediment build-up and help your system run more efficiently.

Change the Anode Rod

Changing a broken anode rod will prevent your tank from rusting and corroding, both of which are causes of premature breakdowns.

Water Heater Services

Water Heater Repair & Installation Services

Whether your water heater is making a knocking sound or breaks down altogether, call our team of licensed plumbers by phone at (703) 543-9649. We offer exceptional water heater repair and water heater installation services in areas of Virginia such as Alexandria, Ashburn, Centreville, Reston, Arlington, and Burke. Our technicians are on-call 24/7 to help you whenever you need it. In addition, our team of technicians offer other types of plumbing services such as gas line installation, sump pump repair, sink replacement, and sewer line installation. Our staff is committed to resolving your plumbing issues and restoring comfort to your home.

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