This is the last installment of a long design and learning process. Thanks to all of you who helped me on my way to this point. Below is the final solution and I would like to check with you if I selected the right fittings

The overall diagram is in the second picture attached to this question. I am building the green pipes now and the orange ones in the second step (when I renovate the main floor bathroom). This green segment is mostly dry vent. There is a drain portion from the new sink to the shower drain. Also there is a wet vent portion for the shower

The orange pipes are to be build in the second stage in order to connect the green vent to the upper part of the soil stack that works as vent for its upper segment

The yellow pipes are "good to have" but I think this should work without it. They might possible be required for the bottom level toilet which used to have a vertical dry vent where the grey pipe left over is (that segment will be capped and under the slab). That vertical segment was cut.

In the first picture I have numbered the fittings and below is their description.

❶,❷,❼ -sanitary tee
❸,❹,❻,❽ short 90 elbow
❺ 45 wye that connects the shower
❾ 90 elbow if they yellow segment is not built, sanitary tee if it is built ❿ 90 elbow if built

I have doubts regarding ❸ and ❹ as these points are prone to clogging These should be long elbows. While ❸ will be ok if it is like that ❹ will push the pipe to low and since I will be connecting to an existing pipe I will need to open the floor for a segment longer than I might want.

Do you see any errors with the above ?

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1 Answer 1


I cannot speak for the rest of the states, but in WA state, there are clean-outs needed at the sink location, and perhaps at the toilet too. The sink clean out would go between 1 and 3, just below 1 in the cabinet so the tail pipe and trap would not need to be removed in case of a clog.

The green line is needed, but the yellow line is not, as long as the toilet is already vented with an existing tie in. I suppose that is what the un-terminated gray line is depicting.

Otherwise it looks good, but to let you know, I am not a licensed plumber, nor plumber, I just been in the business of home building a really long time and I know a few things... Not a lot, just a few....

  • that grey pipe is a leftover of a pipe that I will cut ..see my other posts around here. It was in a wall that I wanted to get rid of. The basement toilet can vent through the soil stack . The grey vertical pipe was there because the lavatory used to be there before it was moved to where I am moving it from today So that grey pipe used to be a dry vent for the sing that was near the purple pipe and to a degree wet vent for the toilet. Then the white pipe that comes off the soil stack was added and the sink was connected somewhere midway between the current shower position and the soil stack)
    – MiniMe
    Aug 25, 2020 at 4:46
  • This post is not to validate that design but to validate the fittings You are right I am planing to add that clean out and another one jst above point 2 that will be accessible from the other side of the wall from within a cabinet (its read end) I will mask it there nicely
    – MiniMe
    Aug 25, 2020 at 4:47
  • The "looks good" affirmation was regarding the fittings as well. That's why the mention of the clean outs, to add to the fittings list. If you add the yellow pipe, would be better then than using the soil stack as a wet vent, IMO.
    – Jack
    Aug 25, 2020 at 4:58
  • Thank you!. Let me ask you the question I asked myself, in what circumstances will the yellow pipe become useful ?
    – MiniMe
    Aug 25, 2020 at 12:13
  • It is the dry vent for the toilet that has the disconnected vent line. Tie it in low enough to be no farther than 5' from the toilet it services. That may need a 4X4X2 wye, @ #11 to prevent gray water from entering the vent.
    – Jack
    Aug 25, 2020 at 14:04

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