Pipes knocking when no water is running and boiler off !!

14 Sep 2011
Reaction score
United Kingdom
What could cause the pipes to knock when there is no water running or and the boiler is switched off ??!!

Does this indicate that I have a water leak and the water is refilling, thus causing the knock ?

Any assistance would be very much appreciated.
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sure it's you and not a neighbouring flat/house?

are you on a cistern fed system or mains pressure throughout?
sure it's you and not a neighbouring flat/house?

are you on a cistern fed system or mains pressure throughout?

We have a semi-detached house. It sounds like it is from within our house and near to the stopcock mains run which is sited below our pull out larder. I installed this to hide the pipe runs up to the tank in loft.

The only thing (problem) we have is a secondary stopcock had to be fitted directly after the first stopcock in the kitchen. The reason for this is that the original mains stopcock was corroded and leaking, I wanted to change it but could not turn the mains water off outside as there is no mains stopcock in the street !! We called Thames Water out who said there wasn't one and it wasn't their responsibility to provide one. As a result I managed to turn the old one off and fit the secondary one directly after it and turn the old one back on and tighten the nut on the old so it didn't leak. Now we have a fully functioning stopcock should we need to turn the water off in an emergency. Could this be causing the problem ?

Since the above problem I have complained that we have a knocking noise and I require a stopcock from the street installed, so I can remove the old stopcock internally to see if it rectifies the problem. :(
Anyone else with advice please.

Is it possible to have this knocking when no water is being used ? Would this indicate a water leak somewhere ?
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Do you have a water meter? If so, leave everything off and note if the meter numbers turn.
I'll go into the street and flagellate myself. What a silly-billy.
Getting ridiculous now !!

Constant clonking, even when no water is, or has been running. Does this indicate a leak somewhere ?!! :cry:
Tie up the valve on your header tank (assuming you have one) to see if it's that that's causing it near to when it's full.

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