I am trying to add plumbing to a wall hung toilet. The drain and vent connections are done as shown in the picture. Is there any problem with this setup? The part I am not sure about is whether the 1-1/2" drain pipe coming from the sink can be connected to 3-in line before the toilet vent, or should I connect it after the 2-in vent? If it is allowed, connecting it before the vent makes a much cleaner setup and prevents some other complications.
