Have you ever experienced a loud hammering noise or pipe rattling in your walls or ceiling? The noise is not only a nuisance but can be quite alarming, especially if you are unsure about what it is. This fairly common sound is referred to as “Water Hammer,” and it occurs when you quickly close a faucet or valve.

Water Hammer, also called hydraulic shock, is “a sound of concussion of moving water against the sides of a containing pipe or vessel,” (State of Illinois Plumbing Code). Water Hammer is the result of a rapid deceleration of water flow in an enclosed space, like a pipe. There are a few ways to remedy this problem, requiring simple parts and know how. A water hammer arrestor, for instance, is a device utilized to absorb the pressure surge when water flow is suddenly stopped. A device called an air chamber may be required in lieu of a mechanical water hammer arrestor. An air chamber is an extension of the water supply pipe near the pipe fixture that provides the air cushion to absorb hydraulic shock. If you look at the picture below, the pink lines you see are the actual “air chambers” while the other lines are the hot and cold water supply, and the waste and vent pipes.

When filling a water supply system, any air in the system will be pushed to the air chambers. Over time, the air in the chambers dissipates and water hammer begins to occur.

How can I eliminate water hammer from happening in my home?

Most homes in the Chicagoland area utilize air chambers. Here is one way to potentially stop the “Water Hammer” noise:

• Turn off the main water supply valve for your home. This should be located near the water meter or at the point your water supply pipe enters the home.
• Open all faucets, tub and shower valves and let the water drain out of the system. Let as much water out of the system as possible by opening a faucet or valve located at the lowest point (probably a basement or hose-bibb if slab on grade) possible.
• Once the system is drained, close all faucets and valves that were opened.
• Slowly turn on the main water supply until the system is full.
• SLOWLY open all faucets and valves again to allow the water to completely fill the system. Be careful when opening faucets and valves, a mixture of water and air will come out of the faucets and might make a mess of you or your bathroom. Open slowly until the air and water mixture is gone.

The water supply system air-chambers should now be recharged with air and help eliminate water hammer.

One of the drawbacks of this process, especially in older homes, is that the faucets might not flow properly because of debris in the aerators.  If this occurs, simply unscrew the aerator, clean out the debris, and replace the aerator.

If you have questions about this process or would like a technician to help, please feel free to call (708) 371-4900 to set up an appointment or talk to one of our staff members.