: On a concreate slab foundation; How far from the inside edge of the concrete form do you locate the drain pipe for the commode.

William,
The "rough" plumbing for a comode (toilet) would be 12" from the back (finished wall) and 15" from either side (finished wall)

To determine the distance from the foundation, would require knowledge of how the framing will be done. Sometimes, the furring is done with 2x4's used with the flat side, and sometimes on edge. Terry