My septic system has failed and I need to connect to the city sewer. My contractor/plumber suggested rerouting the sewer drain from the back of the house and going out UNDER the foundation at the front of the house instead of drilling through the foundation. Is this safe, or would it affect the integrity of the foundation?

Thanks in Advance

Under the foundation is fine and won't hurt the structure. There really isn't any space to try to drill through anyway, the foundation usually starts immediately below the basement floor.

Why not go around the house?

I say go under the foundation, as your plumber suggested. Digging around the house will cost more as you may have to dig past underground utilitys, plus the cost of a backhoe with operater is very expensive. The less time the backhoe is there the better. Not to mention landscape work that may be torn up going completely around the house. It also depends on the area you live in.

Not to mention the further you add to the pipe the more gained fall that it drops in distance.
So the restricted fall form point A to B is not obtainable to maintains Min fall pipe needs to have.