Thanks for the advices. I turned the toilet water off last night. It
seems work. I will retest it tonight to confirm it.



On Jul 3, 7:21 pm, "jmagerl" wrote:
"beecrofter" wrote in message

oups.com...

On Jul 3, 2:30 pm, wrote:
This knocking pipe problem is really strange. It is a weak knocking
sound 2 or 3 times per second normally happened at night time in about
half an hour after all water usage is stopped. Once it started, it
will keep knocking till the next morning. It really drives me crazy.
The only way I found that can stop it temporarily is using water like
flushing the toilet. It will stop the knocking about another half an
hour. So imaging that, wake up by the noise at 1:00AM, flush the
toilet, try to get back to sleep before 1:30AM, if not, flush again...
Anyone can give some advice?

try shutting off the supply to the toilet

Yep. the toilet. The flapper has a slow leak which causes the water valve to
turn on very slowly making all sorts of evil noises. Fix is to replace the
flapper and while you have everything apart replace the fill valve also,

CHeck this by turning off the toilet water and see if the tank drops any
over night