# Where to place water hammer arrestor?



## scottieslg (Jan 5, 2011)

We have a fairly new home, not quite a year old. In our master bath, we kept hearing a banging noise. After quite a bit of trial and error, we have isolated that the banging is located behind the shower wall when the washing machine turns the water off. It appears that placing a water hammer arrestor would be the simplest fix for this. 

My question is where to place this? The washing machine is at one end of the house and the shower is at the other end. Do I place it closest to the washing machine or the shower? Or does it matter?

I have noticed this also happens occasionally when the toilet is flushed or the bathroom faucets are turned off, although not to nearly the extent as the washing machine.

The basement is un-finished right now, so getting to the pex should be easy enough.


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## VIPlumber (Aug 2, 2010)

Water hammer occurs where there are quick opening/closing valves, ie - washing machine. So it's best to install as close to the source as possible. If you install the attached whats in the attached pic, then it should be :thumbup:.


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## AllanJ (Nov 24, 2007)

You will need the arrestors at the washing machine faucets and more arrestors at the shower faucets.

The toilet needs its own arrestor but you might get away with one arrestor for both toilet and shower, mounted just before the pipe branches off for toilet and shower.


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## scottieslg (Jan 5, 2011)

Thanks!

Is that a valve that has a water hammer arrestor already attached, or is it threaded on?


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## VIPlumber (Aug 2, 2010)

It's already attached.


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## Pistol Pete (Sep 23, 2010)

They make some that attach with the hose connections.

http://www.castlewholesalers.com/SIOUX-CHIEF-660-H-Laundry-One-Fixture-Water-Hammer-Arrester.html


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