I am a contractor with a fair amount of knowledge, but have never plumbed a bathroom in a basement. I have a 4" sewer line located in the center of my bathroom layout. The sewer line is at its lowest point in the basement near the house trap. I know I will need a
3" line for the toilet, a 2" line for the shower and an 1 1/2" line for the sink. I have no problem with the plumbing for the sink, but I am not quite sure where the vent for my shower and my toilet will come from beneath the slab.

Can someone give me a basic diagram showing the plumbing beneath the slab.

Can someone please offer me a little help on this diagram. Any help would be appreciated.

Pete

Post size of the bathroom showing location of door and that 4" pipe...

There are 100 ways of laying it out .Sketch will greatly narrow it...

I'm new at this and am not sure how to get a diagram into this.

Here is sketch of toilet and shower drain rough-in. See if it works for you...

A diagram of my bathroom layout is attached.

Ok, that helps... Here is one of few ways to rough it in. The white circles are vents...

Now since you are on slab, you probably don't want to dig too deep. If that's the case, you can utilize this option...

At the end of 4" pipe you install long sweep 90, run it above ground and install 4" clean out. Then you can reduce to 2" run it to the ceiling and connect with shower and sink vents. Continue above the roof with this 2" vent or connect on floor above with existing vent.

Thanks so much Milo. I will break up the floor tomorrow and see exactly how far below the floor the sewer line runs and choose my best option. I think I can see now how to do this. I have to submit drawings to the town. So when I see it I can draw it up. A rather backwards way of doing it, but since it is my own home, it makes things a little easier - in my warped mind!

I don't know where you are located - but in my area, City requires only position of fixtures. And I work under one of the toughest Codes in the country. They leave the rough-in up to attending plumber. There is really no way of telling how you're going to run it unless you establish location and depth and size of your existing under-slab sewer. So, give them general drawing and proceed according to existing plumbing.

I noticed you drew 4" existing sewer to your sketch. You can rough it as this sketch shows...