What is water hammer?

When a valve closes or an appliance like a washing machine cuts off its water supply, the flowing water inside your pipes stops suddenly. That abrupt halt creates a pressure shock wave that travels backward through the system, causing the distinctive banging or clanging sound known as water hammer. The noise comes from pipes moving against mounting brackets or walls as the pressure surge hits them.

Water hammer is more than just annoying. The repeated pressure spikes can damage fittings, joints, and connections over time, potentially leading to leaks or burst pipes. Older homes in Columbia often experience it because the plumbing systems were not designed with protective devices, and the problem gets worse when water pressure runs high in your supply line.

Plumbers fix water hammer using arrestor devices (also called shock arrestors or water hammer arrestors). These small cylinders contain a spring and air charge that absorb the pressure shock before it propagates through your pipes. Arrestors are typically installed near the point where the problem occurs, such as at a fixture or along the main supply line. A few key installations can eliminate the noise and protect your system from damage. If you hear banging in your walls when you turn off faucets, a licensed plumber can diagnose the issue and recommend arrestor placement to resolve it.

Finding a plumber experienced in leak detection and repair is useful if you suspect water hammer has already caused damage to your system.