I'm working on a basement that has roughed in plumbing for the sink, tub and toilet. I need to move the shower drain by about 3 feet (screwdriver marks the approx destination). As you can see from the pictures I already broke the concrete and I'm almost ready to start running the pipe. The sink rough-in is out the way and not in a good location either. I have the following questions:
1. Can I hook up the sink and the tub on one (shared) drain pipe? I was thinking on putting a Y-connector where the current P-trap resides and run a pipe upwards for the sink and then continue the pipe horizontally towards the tub...
2. I know that the drain pipe needs a 1/4" drop per linear foot. But does the drain pipe need an air vent of any sort? Or is the tub and shower over-flow act as an air vent?
You should be o.k. to put a 2in wye behind the trap and run the branch of the wye over to where the lav is going, off the lav fiting you will need to run a vent; run 2in until you are above the concrete and then you can reduce it to 1 1/2 for the vent.