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Spotlight on Water Hammer

Monday, August 3, 2015 - 3:31pm

Water hammer is a common home plumbing problem that causes a knocking or banging noise when you shut off water running from a tap or showerhead. This noise can also occur during washing machine or dishwasher cycles. Although you may view water hammer as only an annoyance, the circumstances that cause it can damage your plumbing over time if left unaddressed. There are several solutions for water hammer that will not only restore peace and quiet in your home during plumbing use, but protect your plumbing from problems in the future as well.

The Cause of Water Hammer

Water hammer is the result of the water in your pipes coming to an abrupt stop when a tap is closed, arresting the flow of water. Modern plumbing systems are designed to include small air chambers, which compress when a tap is shut off to prevent water hammer from occurring. However, if your plumbing does not include air chambers or these chambers have become clogged with grease or limescale, you will hear one or more knocking sounds when you shut off your home’s water. Alternatively, if your water pressure is too high and water is moving too quickly through your plumbing system, your air chambers may not be able to adequately cushion your pipes when the flow stops, also causing water hammer to occur.

The Cures for Water Hammer

There are several possible solutions for water hammer, depending on the reason for the problem. If your plumbing has only recently developed water hammer, it likely has the air chambers required to eliminate it, but they are clogged and no longer contain the air needed to stop water hammer from occurring. This problem can be solved by clearing all the water out of your plumbing system. To do so, shut off your water heater and your incoming water supply, and then open a few faucets in your home to begin draining the water from your plumbing system. Complete the process by opening an outdoor hose bib, which allows water to drain from the lowest point in your home. Once no more water exits the system, close all the faucets and hose bibs and restore your water heater and incoming water supply. If you believe your water hammer problem is caused by excessive water pressure, talk to your plumber. Another solution may be to have your plumber install a small device called a water hammer arrester at key points in your plumbing system, which provides an added cushion of air for improved shock absorption. Finally, if your home’s plumbing doesn’t include air chambers at all, talk to your plumber about your options—he can either install air chambers or use arresters and other devices to prevent water hammer from causing progressive damage to your plumbing.

Even small plumbing problems can build up into larger issues over time—your Vancouver plumber is on your side when it comes to evaluating and solving your home’s plumbing problems, large or small. Please follow us on Facebook, Twitter, or Google Plus to keep up to date on the latest plumbing information and tips!

Have you ever had a problem with water hammer?

  • Never, but I’ll know what to do if I hear it.
  • Yes, our plumber has helped us eliminate it and now our home is nice and quiet.
  • I never knew that strange sound was my plumbing!

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