The soil is the system. As such, the area for the soil absorption field must be protected before and after installation. As stated in Indiana State Department of Health Rule 410 IAC 6-8.3, “No construction on the residential sewage disposal system may take place if the residential sewage disposal system site is disturbed or altered after the on-site evaluation by the addition of fill material, (other than construction necessary for the residential sewage disposal system) or by cutting, scraping, compaction, or the removal of soil, until a new evaluation has been conducted and a modified permit has been issued.” According to the rule, all Indiana septic systems must discharge into the soil. For soils to be suitable for a septic system absorption field, they must not be compacted or have fill. Compaction reduces the ability of a soil to disperse and treat wastewater effluent and can lead to system failure. Septic systems cannot be placed in fill due to the inability to predict permeability from the disruption of structure and the variability of the soil. The more natural and undisturbed the soil on your lot, the better your septic system is likely to perform. Do not put any structure on top of or immediately down slope of the soil absorption field. This office recommends a set-aside area for another soil absorption field in the event of system failure or future additions to the home.