Preventing Water Hammer

A homeowner securing copper water pipes to a wall.
What You'll Need
Air chambers
Large water supply lines
Water hammer arresters
Pipe strapping

Water hammer is the sound made by water being abruptly halted after moving full blast; it is created by the closing of a valve. The force of the running water gets transferred into loose fitting pipes and into the framing and fixtures of your home and sets off a loud bang that's hard to ignore.

Water hammer often occurs in dishwashers and washing machines since they use fast acting shut off valves; although it can happen in conventional faucets and toilet valves as well. Left unresolved, water hammer can damage your plumbing system, as pipes can be jerked out of position which could cause leaks and ruptures.

Preventive measures can protect your plumbing system from jarring and damaging shocks that could undermine the integrity of your water lines.

Step 1 - Secure Plumbing

The most basic remedy is to make sure that your pipes are mounted securely and wrapped with pipe strapping to fix them firmly in place. If pipes shake easily when water flows through them it means that they are not secured properly.

Step 2 - Install Air Chambers

Install air chambers to allow excess pressure to exit. Gauge pipes should be larger than the water supply pipe and should have a removable cap for easy cleaning of build up and residue. Air chambers are filled with air and act as shock absorbers when rushing water flows through the pipes. Being non-mechanical fixtures they generally last a lifetime; although they can become waterlogged and lose their effectiveness. Hence, you will need to drain air chambers periodically of surplus water to maximize their pressure absorption capability and to prevent the build-up of debris and bacteria.

Step 3 - Water Hammer Arresters

Bolt engineered water hammer arresters in easy to find locations in the plumbing system. Water hammer arresters need to be periodically repaired or replaced, so it is better to screw them in place rather than to solder them to the plumbing line. For home applications, water hammer arresters can be used independently or as a supplement to air chambers. They have a slightly more complex configuration compared to air chambers and absorb shock and pressure better. Water hammer arresters were originally designed for commercial applications since industrial pipelines are normally subjected to high intense water pressure.

Step 4 - Install an Adequately Sized Water Line

If repiping is an option, install an adequately sized supply line into your home to ensure that water entering the pipes flows at no more than 5 feet per second. A large water supply line is a very effective defense against water hammer since the pipes are big enough to handle the pressure when rushing water gets abruptly stopped in its tracks.

Step 5 - Drain and Maintain

In addition to all this, have a highly qualified plumber inspect your water pipes and lines at least once a year. A good plumber can also give you tips on how you can extend the lifespan of your plumbing system and prevent leaks and choose good quality materials for your water system and pipes big enough to handle excess water pressure.