Knocking pipes

kopicbloodaxe

I have an extremely annoying problem with what I think is the cold water supply to my house. At tortuously regular intervals (usually around 18 seconds) there's a knocking noise coming from under the sink. Placing fingers gently on pipes leads me to believe it's the cold water pipe. I find that running the cold tap at full force and then leaving it at a steady dribble stops the noise for a while.

Does anyone know what might be causing this? I want to avoid calling plumbers or calling on my new plumbing/heating cover if possible and I'm hoping that this could be a simple problem/fix.

One additional piece of info - I had the water company turn up announced a few months ago saying they had detected a leak outside my house. Luckily it was on their side of the meter so I didn't have to pay. We only noticed the noise a few weeks ago, long after the leak was fixed, but that's not to say it wasn't there earlier... we just didn't notice!

It keeps me awake some nights... just laying there waiting for the next knock. Driving me mad!

Thanks!

Mr_Warren_2

The water pressure coming inside your house might be too strong. Locate the waterboard main stop-tap and turn it clockwise in order to reduce pressure/flow of water inside. This generally works.

ormus

also make sure your pipes are fixed with pipe clips at the minimum distance. a lot of noise is caused by pipes moving and banging.
increasing the number of pipe clip fixings can help.

kopicbloodaxe

Mr_Warren wrote: »

The water pressure coming inside your house might be too strong. Locate the waterboard main stop-tap and turn it clockwise in order to reduce pressure/flow of water inside. This generally works.

Would this be the stop-tap inside the house or outside by the water meter?

Would dropping the presure in this way affect my combi boiler? or even worse than that, make my lovely shower not so lovely? ;-)

Canucklehead

Hi

It's not a pre- existing problem so I would look to the ball valves in your house, the toilets and ,if you have one, a cold tank in the roof. Possibly one of them needs a new washer and/or is partly blocked.While it's performing have a look at them.
Is it coming from your house?

Corgi Guy.

P.S. Did you notice an improvement in water pressure after the leaking main had been repaired? Turning the stopcock down will have a negative impact on your combi i.e. restricts mains water supply

takoo

Hi Kopicbloodaxe

May not be of help but the central heating system sometimes gets air in one or more pipes. The sounds and vibrations travel around the house so it may be worth considering.

With the system off bleeding the radiators sometimes dislodges the air pockets.

Where the air and knocking sound seemed to be in the boiler a proprietary fluid was been circulated and the system in effect drained to clean it out.

Also consider the heating coming on. The warm / hot water may cause the pipes to expand and cause creaks and a seeming knock.

Finally, check that insulation (if any) which should be covering the outside meter has not been dislodged. If it has the recent cold spells may have caused the pipes to facture.

Happy hunting

Takoo

dugowly

Option 1
lag the cold water pipe under the sink to reduce the amount of travel

Option 2
If there are sink isolator valves under the sink, turn them a fraction tosee if that helps
Option 3
Wear ear plugs when you go to bed
Option 4
Consume excessive amounts of alcohol prior to retiring for the evening
Option 5
Any combination of the above