Conventional septic tank systems cost $3,500 to $8,500 to install the systems people are most familiar with. These conventional systems are primarily gravity fed and use anaerobic bacteria to break down solid waste in the tank.
The system consists of a septic tank, a drainfield, and 3 feet of native soil beneath the drainfield. A septic tank is a large, underground container that treats wastewater from rural homes that are not connected to a municipal sewer system. A drainfield, also called a leach field, is the area of land where the wastewater is dispersed and treated. The drainfield is made up of a series of perforated pipes buried in the ground and surrounded by gravel or sand which filter the wastewater.