Which of the points 1,2,3 is the best to connect the drain of the new sink in the below picture? The green pipe you see in the wall is a dry vent (it will replace the vertical grey vent you see in the picture) The white pipes are 1.5" ABS and for the common section I would assume it is 2" (for now it is under the slab, I can't see it)

To avoid breaking more floor I could run the drain for the new sink through the wall and land near the shower drain end and add a common dry vent there. Is that a viable option?

In the end it will look like this enter image description here

  • As long as it’s under 5 or 6’ to the vent it should be ok I am not a plumber but have don quite a few houses we always used 5’ but I think 6’ is code.
    – Ed Beal
    Commented Aug 18, 2020 at 23:22

1 Answer 1


I would use a wye fitting on pipe # 3, run pipe coming off wye (45 degree angle) and use and 45 degree fitting to line up with center line of new sink,use a medium sweep to turn up clean out tee and then 2x2x11/2 santee at proper height Approximately 20” from floor of bathroom . Run vent up wall ,over and above finished ceiling and tie into new dry vent of same size or bigger

  • Hi Rasta, thanks for the reply any reason for specifically choosing that point?
    – MiniMe
    Commented Aug 18, 2020 at 3:52

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