Can a New Washing Machine Cause Water Hammer?

Water Hammer

• Water hammer is the common name for hydraulic shock, a phenomenon caused by sudden increases or decreases in the velocity of water flowing through plumbing. If a valve inside a plumbing pipe opens or closes too quickly, for example, high pressure water traveling at high velocities inside the pipe produces a distinct thud or banging sound when it encounters a solid obstacle. It is this banging sound that often serves as indication to homeowners that one of their water appliances has a water hammer issue.

Washing Machines

• Whether old or new, a washing machine is capable of causing water hammer since water travels through the hot water and cold water connections. Water hammer is probably less likely on a new washing machine, since wear and tear and malfunctions contribute to the conditions that make water hammer possible. In fact, water hammer is often caused by conditions outside of the washing machine altogether, such as low water pressure at the hot and cold water connections.

What to Do

• Some simple troubleshooting can identify the cause of your water hammer. Attach a pressure gauge to your washing machine cold water connection. Turn off the water supply to other appliances in the home that use water and turn on the cold water connection faucet -- if the gauge indicates anything higher than 60 psi, high water pressure at the cold water connection could be causing the water problem. As a temporary solution, you can partially close the shut-off valve to the washing machine. But to fully resolve the issue, you will need to contact a plumber regarding repairing the washing machine's water supply so that it supplies a safe water pressure level to your washing machine.

Prevention

• After adjusting your washing machine's water pressure back to safe levels, it is important to take steps to prevent future water hammer problems should the water pressure to your washing machine fluctuate again. Water hammer arresters are small, inexpensive devices sold at plumbing supply stores that, when installed on the washing machine's water supply connections, will prevent water hammer. Install per the manufacturer's directions.