Hello! I plan to add a bathroom to my unfinished basement and would welcome some advice. I plan on putting in a shower, vanity, and toilet.
As the current plumbing down there goes: the 4 inch cast iron stack to the first floor bathroom is in the center of and about a foot from the north wall, there is a floor drain under the lower end of the stairwell at the east end, and there is a 2 inch cast iron drain line from the first floor kitchen on the southeast corner with the washing machine PVC drain attached to a 2 inch cleanout just above the floor. Everything on first floor is PVC to the cast iron drain lines save the toilet and the vent coming off the toilet elbow at the very top of the main stack.
I would like the bathroom to be underneath the first floor bathroom where the 4 inch stack is. The first picture is what the stack looks like at the top and the second at the bottom.
What I'd like to know is can I install a back-outlet toilet (found one with 7 inch high rough-in required) to the 4 inch cleanout (with another cleanout installed in-between), and the sink and shower installed to the smaller 2 inch cleanout on the floor aimed west? If this is good, how do I put a trap in for the shower? I would put all that plumbing in the picture inside a "plumbing" closet. I'd like to put a closet next to the plumbing closet and between the shower and outside wall for the room next to the bathroom (making up the east 1/2 of the bathroom) but that would mean the shower drain would need three 90° turns and one 180° turn to get to that cleanout.
All is in planning stage, nothing concrete save the bare floor.