Stop Banging Pipes Fast: Install a Water Hammer Arrestor

Got a washer that turns your laundry room into a drum‑solo concert? The bang you hear isn’t a loose pipe—it’s water hammer, a shock wave that hits when water stops suddenly. In the next few minutes you’ll learn exactly how to install a water hammer arrestor so the noise disappears the first time you run a cycle.

What Is Water Hammer?

When a valve (like the one in your washing machine) shuts quickly, the moving water slams into the pipe wall, creating a loud “hammer” sound. The fix isn’t tighter fittings or higher pressure; it’s giving that sudden surge a cushion to absorb it.

Tools You’ll Need

• Pipe cutter or hacksaw
• Adjustable wrench
• Teflon (PTFE) tape
• Water hammer arrestor (push‑fit brass works well)

All of these are standard at any hardware store and cost under $20 total.

Installing a Water Hammer Arrestor

1. Shut off the water – Turn the two valves behind the washer clockwise until they stop.
2. Relieve pressure – Open the washer’s inlet tap and let any water drain into a bucket.
3. Mark the cut – Locate the cold‑water line right where it exits the wall, about an inch from the valve.
4. Cut the pipe – Use the cutter (or hacksaw) to remove the marked section.
5. Deburr – Smooth the cut edges with a file or sandpaper.
6. Wrap threads – Apply 2‑3 turns of Teflon tape to the male threads of the arrestor.
7. Fit the arrestor – Slip it into the gap, hand‑tighten the nuts, then give each a ¼ turn with the wrench—don’t over‑tighten.
8. Restore water – Open the supply valves slowly, check for leaks, then run a wash cycle.

If the bang persists, repeat the process on the hot‑water line for extra damping.

Testing & Fine‑Tuning

• Listen: After the first cycle, the noise should be gone or dramatically softer.
• Check for drips: Tighten any leaking fittings a half turn at a time.
• Add a second arrestor only if a faint thump remains; most homes need just one.

Quick FAQ

Do I need a plumber?
No. With the right tools and a few minutes, DIY installation is safe and reliable.

Can I use a different size arrestor?
Choose an arrestor that matches the pipe diameter (½‑inch or ¾‑inch are common for washers).

Will this affect water pressure?
No. The arrestor only cushions sudden stops; normal flow remains unchanged.

Silencing water hammer is as simple as adding a small cushion to your pipe system. Grab a water hammer arrestor, follow these steps, and enjoy a quiet laundry room without a plumber’s bill.