Random banging from water pipes

[KRob]

Hi,
Could really do with some help on this one please.
About six months ago my water pipes developed a random banging. Sometimes it a single loud bang and sometimes a string of smaller bangs - or anywhere in between...
It's not water hammer (as I understand that phrase) as it's not related to any water usage in my house.
Can happen at anytime but what I do know is that it is happening more often at night now - to the point of waking me up 4-5 times every night.
I have worked out its the main incoming pipe that is banging. I can feel it next to the house stopcock and I can feel it upstairs where the water tanks are. The other pipe do not suffer from this so I think it is happening due to something outside my property. But no ideas what.
My house is terraced with about 8 houses in the line and I think there is a shared mains stopcock out on the road somewhere but no idea where.
Any ideas gratefully received.
K

 

[JCplumb]

It could be a numberof things. Somewhere in your property or on the shared main water is being used which is causing the noise.
Fitting a water hammer arrester close to where the noise is loudest may stop the banging.

 

[gasmanrob]

Is your mains pressure pretty impressive?

It could be that when someone in your street uses their water you loose a bit of pressure then as they shut their tap your pressure is increased suddenly. But I thought new msn style suppliers pits had check valves built in to prevent back flow. Subsequently causing us issues in some people's houses with thermal expansion but that's another story

 

[wiggers]

I would start by replacing your internal stopcock as it's highly likely this is the problem if it's still occuring try replacing wc fill valve or float valve on CWSC in loft if you have one pipework may also be loose.
Last one taps get replacement tap conversions
These all cause noise in some way but from what you have said stopcock will be my target
Good luck!

 

[KRob]

Hi,
Thanks for the replies.
Yes pressure is pretty good. But I've tried adjusting the pressure to a variety of positions and it doesn't make a difference.
I have had a plumber out who had a quick look and said there was nothing wrong but he didn't hear the noise as it is random. I also asked Severn Trent about it, they sent someone round who changed the meter but no luck there either.

 

[KRob]

Actually had the float items in the water tanks replaced too as that was quite easy.
Double checked all the pipework I can get my hands on and nothing is loose. When it happens you can feel it quite hard when holding a pipe.
As it's only on the mains incoming water pipe I guess main stopcock would have to be next up if you think it's worth a go.

 

[nicro3]

Have you any dripping taps, check cartridges as this can be a cause

 

[KRob]

Could it be the taps? Those pipes don't vibrate at all, only the inlet ones - but will investigate any possibility.