How to stop water hammer
We'll stop the banging with arrestors, pipe straps, or pressure adjustment.
What you'll need
- Water hammer arrestors (match the thread size of your supply lines)
- Pipe straps (if pipes are loose)
- Adjustable wrench
At a glance
- Water hammer occurs when water stops suddenly and the momentum creates a pressure surge—pipes bang.
- Install water hammer arrestors at fixtures that cause the noise (often washing machine, dishwasher, or quick-closing faucets).
- Secure loose pipes with pipe straps—movement amplifies the noise.
- Lower the water pressure if it is very high—a PRV can reduce hammer.
- Call a plumber if the pipes are in walls and you cannot access them.
Quick triage — pick your path
Get started
Choose the option that matches what you see. You can jump straight to that section.
Steps
Goal: Stop the banging when you turn off a fixture.
- Identify which fixture causes the hammer. Install arrestors at that fixture.
- Good: Arrestors are in place. Proceed to Secure pipes.
- Bad: Cannot access the supply—call a plumber.
Secure pipes
Goal: Reduce pipe movement that amplifies the noise.
- Add pipe straps to loose pipes. Space them every 6–8 feet.
- Good: Pipes are secure. Proceed to Test.
- Bad: Pipes are in walls—arrestors may be enough; test first.
Test
Goal: Verify the hammer is gone.
- Run the fixture that caused the noise. Shut it off quickly.
- Good: No banging. Proceed to Verification.
- Bad: Still banging—try lowering pressure or adding more arrestors.
When to get help
Call a plumber if:
- The supply lines are in walls and you cannot install arrestors.
- The hammer persists after installing arrestors and securing pipes.
- You have galvanized pipes and suspect corrosion is contributing.
Verification
- No banging when turning off the washing machine, dishwasher, or faucets.
- Pipes are secured with straps.
- Pressure is in a reasonable range (40–80 psi).
Reviewed by Blackbox Atlas
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