From the United States of America? - Checkout our specific plumbing forum for you:USA Plumbing Forum

Discuss Water hammer despite arrestors being fitted in the Plumbing Forum | Plumbing Advice area at

CorgiDirect - Discounted Corgi Related Documentation and Plumbing Supplies
This official sponsor may provide discounts for members

I am in a row of 4 houses and we have one stopcock in the street and the pipe divides off to each house and each house has a stopcock under the kitchen floor.

The water hammer has been going on for a couple of years and has become gradually worse to a point where I am turning my water off at night to get some peace.

Regardless of which tap or appliance was being used, they would bang when turned on and again when turned off - the latter sometimes being a sucession of bangs. But it is also happening when water wasn't being used - and not just after the tap was turned off, this could be 20 minutes, an hour, or even through the night. It's happening despite my water not being used at the time.

I have had the following work done in my house: the stopcock in my house replaced. I have had shock arrestors fitted at the stopcock, the washing machine fill pipe (not the machine itself), hot and cold taps in the kitchen, both basin taps, both bath taps and the toilet upstairs. I have also had the water company check the stopcock outside and it was fine, but to try and cure my problem, it was replaced. (I had read somewhere that this fixed the problem for someone which is why I asked). All the pipes have been checked for leaks (there aren't any), and fully secured - which they were, but we added a few more clips on the ktichen pipes just to be certain.

The water pressure is at 2.5 bar which I understand is an acceptable level.

Despite all this work, the problem still occurs. I have reduced the flow to my house and it's not ideal as the shower flow is now very poor, but I can at least use my taps if I turn them on and off very slowly.

From everything I have read, fitting the shock arrestors should have resolved my problem, so I am very disappointed that it doesn't seem to have worked for me.

I have asked my neighbours to run their water while I listened for noises, and next door but one I get a dull thud noise and the one attached to me is worse - it's banging and clanging, like well literally, a hammer is banging the pipes. Next door but one hears the attached (middle) neighbour too and it's really loud. I did ask the middle neighbour if they could hear banging pipes and they said no, but there are 9 people in that house, so they probably wouldn't!

I'm really at a loss as to what to do next. I don't understand why my pipes are banging away at random times despite my water not being in use. Surely there must be something outside in the street which is causing the problem? I am at the end of the supply so I believe that's why I'm getting it worse.

I'd appreciate any ideas for a solution.



Gas Engineer
If all is good inside your property, I’d be looking at the neighbouring properties, with sound transference. You sound like you’re on a shared common supply, with probably copper incoming mains (noise will travel along this). This might also be why you’re experiencing the noise when nothing in yours is being ran.


Poxy lever taps. This is becoming increasingly common, sadly.

Have you tried a pressure regulating valve on the mains, set to slightly less than the mains pressure? It will limit flow slightly, but not too much (better than shutting down your stopcock), and should mean that your water is effectively shut off when you aren't drawing water...


Gas Engineer
Any dead legs?
Can the mains cold water be clipped and secured under floor boards?
Fit flow limiters to each outlet rather than winding down the stop tap.

Reply to Water hammer despite arrestors being fitted in the Plumbing Forum | Plumbing Advice area at Plumbing questions, answers, tips and tricks.

Plumbase - Plumbers Forum Sponsor
This official sponsor may provide discounts for members

Plumbing and Plumbers

Plumbing Workwear

Shower Power Booster

Plumbase Spares - Plumbing Supplies and Spare Parts

Water Underfloor Heating

CORGI Direct for Plumbers

The Wetroom Store

Plumbase Spares

New Posts Threads Members