A typical septic system has four main components: a pipe from the home, a septic tank, a drain field, and the soil. Microbes in the soil digest or remove most contaminants from wastewater before it eventually reaches groundwater. The wastewater exits the septic tank and is discharged into the drain field for further treatment by the soil. The partially treated wastewater is pushed along into the drain field for further treatment every time new wastewater enters the tank. If the drain field is overloaded with too much liquid, it will flood, causing sewage to flow to the ground surface or create backups in plumbing fixtures and prevent treatment of all wastewater.