Toilet Venting when the toilet is next to the edge of concrete slab where DWV exits from the building and the from toilet is close to the horizontal

[mtsolarken]

I have very little experience in DWV systems. I don't think I have room to properly include a separate vent where the toilet drains into the horizontal main drain that exits the building immediately after the toilet wye. In the image the trench that is perpendicular to the DWV trench is the perimeter foundation trench. That toilet is right up against that trench. The drain/vent for the sinks are within about 48" of the toilet drain

 

[John Gayewski]

Instead of using the 45 for the toilet riser use a street 45 inside of a 4x2 wye.

Or even better instead of doing a wye and 45 coming rolled up on the main. Start slightly farther back and wye (4x3) up, 45 horizontally, then 3x3 wye with 45 for the toilet then continue straight above the 4" by putting a 3x2 bushing into the 3"wye and use 2"for the sink and shower or whatever.

 

[Sponsor]

 

[Breplum]

With little DWV experience, we always say to hire a pro to help you. There are so many ways to mess up in a slab that it is not recommended that DIY do underslab plumbing. I have seen too many failures to list.