People who live in a city rarely think about it because their wastes usually go through a central sewer system to a wastewater treatment plant. Suburban and rural homeowners using onsite wastewater systems however, do need to pay attention because a failure in their system could impact their property, or even their drinking water. Therefore, the proper care and maintenance of these systems is entirely up to you.
Wastes go from the toilet, sink, shower, or washer through the indoor plumbing to the septic tank.
The tank is a watertight, underground receptacle where the solid wastes are broken down by bacteria. As the wastes move through the tank the solids settle to the bottom of the tank and the liquids pass on through to the outlet pipes. As the liquid passes through the tank, lighter particles and grease rise to the surface to form a floating scum layer that remains in the tank. The remaining bacteria and organic matter are absorbed by the soil before making its way to underground water supplies. Solids are always accumulating in the septic tank because the rate of decomposition is much slower than the rate at which sewage is added.