In reply to message posted by paulremnant:
Last night I turned off the cold water to service a tap in my kitchen. After I had finished I turned the water back on and this knocking noise started in the cold water pipe, it has a regular rhythm to it aswell. So I turned all the taps on etc to check there was no air trapped and the noise stopped.
But this morning after I had had a shower about 15 minutes after the noise started again even though it had gone away last night and the toilet etc was used. Does anybody have any idea what is causing this and how I can solve it?
Sounds like a loose washer or a defective ball cock “hunting” we call this in A/C work.
The valve is chattering as it seeks to close.
Check all your faucets and the toilet including the stop valves as most valves under a fixture are Globe type by design and these are prone to this kind of noise.