Toilet Connection to Horizontal 3" Pipe

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I am adding an upstairs bathroom and trying to figure out the DWV system. I am trying to minimize the impact the soil stack will have as it will be going down a kitchen wall (to be enclosed later). I don't have any software to make a fancier drawing, but I have attached what I was able to draw. The toilet will be located right next to the soil stack. Can I use a 3x3x long sweep 90 for the toilet then continue the horizontal 3" drain to the vanity and tub, or does the toilet need to actually branch off of the drain pipe? Because the floor joist are 2x8, I can't run a 3" pipe through it, so the horizontal drain pipe needs to stay in the joist bay. The vanity and tub will have a vent pipe from each fixture that will connect with the main vent pipe in the attic. This is in PA and they follow the 2018 IPC.


  • Toilet Connection.jpg
    Toilet Connection.jpg
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Hey, wait a minute.

This is awkward, but...

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