Soils rich in sand allow rapid percolation to dispose of sewage but do not hold the sewage long enough to treat it adequately before it reaches groundwater. Treatment continues in the soil until rock or soil saturated with liquid is encountered. Rock allows sewage to move quickly into groundwater without proper treatment. Partially treated sewage reaching either rock or saturated soils will enter the water supply. Any contaminants or disease-producing organisms present in the sewage will be in the glass of water you drink from your polluted well.
Viruses can survive in groundwater in excess of one year.
The SEO enters the excavation to evaluate the soil's texture, structure and color. The SEO also looks for signs of rock and saturated soils. If the results of these soil tests show that the soils can properly treat sewage, a system may be installed. If there are problems with the soils, systems designed to overcome these soils limitations, such as an elevated sand mound, may have to be used. If the soils are unsuitable, no septic system may be installed.