I receive quite a few questions about using soil fill to overcome site limitations. Sometimes these questions come before fill is used, but more often the questions are about fill that was placed at or around the time the house was built. When I receive these questions about using fill for septic system installation, I point out that our designs and installation guidelines are based on the use of natural and undisturbed soil.
Usually the question revolves around why engineered fill shouldn’t or can’t be used when my recommendation is for an aboveground mound system to overcome shallow soils over a limiting
