My particular set of construction books doesn't seem to answer the following question:
Can the sewer drain pipe (that directly leads to the septic tank) be routed below slab footings? I remember seeing somewhere a cautionary note about not doing this, for fear of allowing water seepage into a basement.
In my case, the slab is on grade. The intended drain exit is on the down-slope side of the building (the site has a bit of slope to it).
Thanks for any input.
If you use material that is approved within the walls, it can go wherever it needs to even near the surface. I changed Fresno County's MO by arguing with their inspector about this and winning. That was 22 years ago but don't think it has changed yet. Normally you always want to be 12" below the surface minimum. With good workmanship you shouldn't have any leaks to worry about. Wrap the pipe if it goes through concrete- don't let it grab it. If it needs to be sealed around you can do it after the concrete pour. Even cardboard will temporarily keep concrete off the pipe.