Is it possible to attach a sink to a wet vent setup without its own dry vent? I.E. I want to use the existing wet vent for the drainage but I don't want to run a new vent for the sink if I don't have to.

I'm assuming there's no way to do this and that instead I'll have to tie the waste into the wet vent pipe and vent off the sink and tie it to the existing vent stack for the wet vent?

  • A: all wet vents must connect to a dry vent. B: without a diagram and details about what is already draining and venting into these pipes, and their sizes, and the proposed pipes, there's no way to answer this question. It's also not clear that you understand wet .vs. dry vents if you say "vent off the sink and tie it to the existing vent stack for the wet vent?" since that would ordinarily mean a dry vent. Help us help you - sketch, take a picture, edit your post.
    – Ecnerwal
    Dec 13, 2020 at 13:20
  • ...also - far better to do some additional work and have more venting than absolutely required than to under-do the venting at all and end up with sewer gas in the house to save a little work (then) and have to do more to fix it (later.) Err on the side of vented more than required, if erring.
    – Ecnerwal
    Dec 13, 2020 at 13:46
  • The current set up is thus: A tub that drains into a sanitary tee with one end being the 2" dry vent, the other side being the waste. Attached to this downstream is a shower and eventually a toilet. So the section from the toilet to the tub is the wet vent. In the new system, I plan on replacing the tub with a shower and the orignal shower with a sink. Dec 14, 2020 at 19:20
  • There are under sink vents that you might be able to use, but I'm not sure I would really suggest it.
    – Ben
    Dec 14, 2020 at 21:16


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