Here is a rough breakdown of the house in question:

  • A one floor home built in approx. 1960s or 1970s
  • A full basement, unfinished
  • A full attic with blown in insulation

I have been removing some bulkheads in the kitchen that look very similar to this:

enter image description here

I discovered a single, small run of 1.5" copper piping jutting out. The problem is that this copper pipe appears to go from the basement up to the attic for absolutely no reason.

This appears to be the waste water pipe, going directly up from the basement to beneath the kitchen sink - however, it seems to keep going up behind the wall.

The house has no history of dramatic changes or updates, certainly not anything involving a waste pipe being required in the attic.

The only clue is that almost all the copper water supply pipes in the house did something similar - supplying to the spot where they were needed, then running further up the wall a foot or so to be capped off. I believe this was a method for relieving excess water pressure. However, this pipe is a waste pipe, and seems to go much higher - all the way to the attic.

Does anyone know why a waste pipe might run much further up the wall than needed?

  • 8
    It is a vent. Look out side at your roof.
    – Dan D.
    Commented Aug 24, 2017 at 19:59
  • I wondered that - I did briefly look at the roof but couldn't see anything. I'll go up on the roof and check again - many thanks.
    – Toby
    Commented Aug 24, 2017 at 20:02
  • @Dan D., should post this as the answer.
    – noybman
    Commented Aug 24, 2017 at 22:40
  • 2
    @DanD. -- post that as an answer and I'll upvote it Commented Aug 24, 2017 at 23:36
  • 1
    @Dan D was correct - I should have checked more thoroughly, it was a vent. If he posts as an answer I'll mark it as the answer.
    – Toby
    Commented Aug 25, 2017 at 11:41

2 Answers 2


As OP noted in a comment, this is a 1.5" copper vent pipe. He found it poking through the roof.


The pipes going higher than the outlet for their use are an attempt to install water hammer protectors. They will work until the water finally removes all the air in the capped off section. – d.george 12 hours ago

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

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