Septic System: There are four main components to a residential septic system.
- A pipe from the home to the septic tank
Microbes in the soil digest or remove most contaminants from wastewater before it eventually reaches groundwater.
Residential Septic System Diagram

Pipe from the home:
All of your household wastewater exits your home through a pipe that is connected to your septic tank. Just to be sure, this includes all the toilets, showers and bathtubs, wash basins, washing machine, and the kitchen sink.
Septic Tank:
A septic tank is a buried, watertight container typically made of concrete, fiberglass or plastic. It holds the wastewater long enough to allow solids to settle out (forming sludge) and oil and grease to float to the surface (as scum).
The septic tank also allows partial breakdown of the solid materials. Some solids are removed from the wastewater, some are digested, and some are stored in the tank. Up to 50% of the solids retained in the tank decompose, while the remainder accumulate as sludge at the bottom of the tank and must be removed.
Compartments and a T-shaped outlet in the septic tank prevent the sludge and scum from leaving the tank and traveling to the drain field.
Newer septic tanks have risers with lids at the ground surface to allow easy inspection and pumping of the tank.
The septic tank should retain the wastewater for at least 24 hours.
Septic Tank Diagram

Single chamber tank. Click here to see two chamber tank
Drain Field:
The wastewater exits the septic tank through a pipe and flows by gravity 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 septic tank.
If the drain field is loaded with too much liquid, it will flood causing sewage to flow to the ground surface or create backups in the plumbing fixtures in your house.
They are many types of drain field including leach field, leach bed, leach trench, leaching pit, seepage pit and chamber system. Regardless of their name, they all serve the same purpose; to assist with the disposal of your wastewater into native soil.
Soil:
Septic tank wastewater flows to the drain field, where it percolates “drains” into the soil, which provides final treatment by removing harmful; bacteria, viruses, and nutrients. Suitable soil is necessary for successful wastewater treatment. |