I've been noticing a consistent knocking/tapping noise when cold water is running in my house. It gets louder with more volume. It stops when the water is turned off. Not sure how long it's been happening. It appears to be coming from the vicinity of this part. Can anyone tell me what this part is and if there is a valve or something in it that could make this noise? If so should it be replaced? Since the whole pipe is vibrating it's difficult to pinpoint. This is the only part I can find on the water line between the shutoff and the rest of the house. However, given that this was buried in the wall, it's possible there could be something else.

enter image description here

  • can you take a picture of the top of that fitting? – JACK Dec 9 '19 at 19:06
  • Does this tapping occur when the cold water is turned on anywhere in the house or only one place i.e. the kitchen? – HoneyDo Dec 9 '19 at 19:14
  • The short part is the top. The tapping occurs when water is on anywhere in the house. – AdamC Dec 9 '19 at 21:19
  • 1
    the tapping sound could be the water meter, turn on the water, locate the meter and see if it clicks at the same rate as the tapping. – Jasen Dec 10 '19 at 8:24
  • It was the meter! City came out next day, replaced it and the noise is gone. – AdamC Dec 13 '19 at 15:28

That is nothing. It's just a tee fitting with a short piece of pipe that is capped off. That shouldn't make any sounds or cause any issue. As for why it is there - no telling. Installer could have ran out of couplings and had a tee handy, or read a diagram wrong and thought there needed to be a tap there.

| improve this answer | |
  • Try supporting the pipe, especially where it passes through walls. – JACK Dec 9 '19 at 19:12

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.