If you hear a loud thud as a washing machine turns on, that noise is called a water hammer. The banging or slamming noise is caused by a lack of air in the pipes, which leaves no air cushion to absorb the shock of water turning off.
The operation of a washing machine calls for water several times during its cycle so it has an electrically-operated solenoid valve. The valve opens and closes very fast and can create a shock wave in the pipe when the water abruptly stops. The loud noise is annoying, but the shock wave can do real damage by bursting a hose or rupturing a plumbing line. The addition of water hammer arresters—think of them as shock absorbers—usually solves the problem.
A plumber will charge $150, including labor and material, to install arresters at a washing machine. You can buy the devices for $25 and install them in a short time to save 83 percent. The job involves unscrewing the two water hoses to the machine, and then attaching the arresters to the line and reinstalling the hoses. The only tool you'll need is a pair of slip-joint pliers. This project is easy to do, even as a first-time plumbing project. If the water hoses are worn, replace them at the same time to assure continued good service.
Pro Cost — DIY Cost — Pro time — DIY Time — DIY Savings — Percent Saved
$150 — $25 — 0.9 — 1.5 — $125 — 83 percent
