Stopping Water Hammer


Water hammer arrestorIf your home's water supply pipes are banging when you shut off the water to a fixture then you will need to install a water hammer arrestor. Water hammer is caused by the sudden stop in the flow of water through a pipe, often caused by closing a faucet valve to quickly but may also be caused by toilet fill valves, dishwashers and water softeners are a few examples.

Although in the past water hammer arrestors (also known as "shock arrestors) were made by creating an air chamber above the fixture they served, this practice is not recommended because they become water logged and cease to function. The more modern solution is to install a pre-manufactured water hammer arrestor on the water lines as close as possible to the source of the shock.





Installation of water hammer arrestors

  • Water hammer arrestors are typically installed vertically on both the hot and cold water supplies as near the fixture as possible.
  • Depending on the model of shock arrestor you purchased you will either need a soldered tee or threaded tee.
  • These devices should be installed in an accessible location in case they need to be replaced.
  • Apply teflon tape to the threads and use two wrenches, one on the fitting and one on the shock absorber.
  • Check for leaks when finished.

Shock absorber Shock arrestor water hammer arrestor

Other causes of noisy pipes

  • Water supply pipes are not properly secured to the walls.
  • Loose tap washer. If the pipes make noise only when a faucet is running, the cause is likely a worn out rubber washer on the faucet's cartridge.