I am relocating the bathroom door and the toilet vent is right in the middle of the new opening. I want to put the vent in the wall behind the toilet which will be upstream of the toilet. Will this work? The vent is currently about 6 feet in front of the toilet. The shower drain will be connected into the 3" toilet pipe about 3 feet downstream of the toilet.

The image below is what I'm hoping to do, with two different ways to handle the vent connection.

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You are within 6' so it would be allowed in my state.

  • Would the section between the toilet & vertical vent stack just be horizontal (1/4 slope)? Or does it have to be elevated or somehow prevent solids from blocking the vent? – StayOnTarget Dec 21 '19 at 19:42
  • Solids won’t be trying to go up the vent as air will be assisting in either case but in most cases you only have ~1foot so it doesn’t matter. – Ed Beal Dec 21 '19 at 20:52

No on the first proposal. toilets need a wye and 1/8 or a long sweep closet 90. Solids need help being directed. the second is fine. Vent to not be horizontal. Vertical or 45*

  • Solids will not be passing through a 90 in either scenario – Kris Jun 29 '19 at 17:34
  • Hello, again. This is interesting, but a bit hard to understand for most non-professionals. Would you add a bit more info? Thanks. – Daniel Griscom Jun 29 '19 at 17:42
  • Problem is with the first side view. the venting will work, but what you've shown is in effect a sanitary tee on the transition to the horizontal. Not allowed. Too abrupt. That needs a more gradual transition. Wye and 1/8 or a closet bend with a venting wye just downstream, as you did in option #2. Option #2: Make sure the 3x2 wye is not flat in its back. the vent leg should be at a 45* if it is a full dry vent so it stays above the solids and avoids clogs – spencer Jul 1 '19 at 11:49

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