Where does the septic go?

We had Phil (excavator) and Martin (septic) out to look at the site today.    Phil was amazed we hadn't called him to repair damage from the rains (Joe did that with a Terex).

We showed him our house that we planned to build on the site - pushed up to the 75 foot setback line.    Martin said the septic really should go where we were putting the house.   The house would need to go at least 30 feet back.  Phil said we really need to do the house in the hill as a walkout - or we will have too much fill and retaining walls - which is just too expensive.

So.....we are back to the drawing board.   Need a new house and new plan.

On the bright side - this would let us put an attached garage on the house at the top of the hill.