I have a loose pipe that we cannot get to, it is behind a wall. It bangs loudly after any tap/toilet/water appliance is turned off/flushed etc. We put a water hammer arrestor by the washine machine, but it didn't really work as it happens with any faucet in the house.

I would appreciate some advice on how to stop it, since getting to the loose pipe isn't an option. Should water hammer arrestors be within 6ft of the problematic pipe?

  • 1
    Is it behind a wall, or in a wall? What type of wall? Do you have partial access? Details matter.
    – isherwood
    Commented Mar 21, 2022 at 15:50
  • behind a plasterboard wall. Would an arrestor near as possible to the loose pipe be the best option? Commented Mar 22, 2022 at 13:32
  • @DanielNash If it's plasterboard, just open it up and fix the pipe. You'll spend a fortune on dad-gadgets when you could fix this with two screws, one clamp, a cup of joint compound, and a half-cup of paint.
    – J...
    Commented Mar 22, 2022 at 17:06

1 Answer 1


It's likely that the offending pipe is just placed in such a way that even minimal water velocity changes cause it to move enough to bang into the wallboard or framing.

I suppose you could try to add arrestors to every water use-point in the house but that's likely to be a lot of work and not 100% reliable to fix the problem.

Your best bet is to just open up the wall, determine and fix the problem, and then refinish the wall.

  • If it's just drywall, sure, but it could be a nasty proposition if, for example, there is a very expensive tile job on the wall... and something similar on the other side as well.
    – J...
    Commented Mar 22, 2022 at 0:36
  • If that's the case hopefully there is some way to access it from the other side but you're right, it could be a problem.
    – jwh20
    Commented Mar 22, 2022 at 10:24
  • I have managed to find what i believe to be the offending pipe, or at least the start of it, and its going to be impossible to fix it to a wall/plasterboard to be honest. Should I get a plumber in to put a arrestor on the offending pipe? Commented Jul 1, 2022 at 13:00

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