What is the function of a septic tank?

The primary function of a septic tank is to treat and store wastewater collected from a household. When wastewater enters the tank, it undergoes a natural process where solids settle at the bottom, forming sludge, while lighter materials like fats and oils float to the surface, creating a scum layer. This separation is crucial because it allows the liquid effluent to exit the tank more cleanly into the drain field, where it can be further treated by the soil.

The septic tank is designed to hold wastewater long enough for this initial treatment to occur, reducing the solid content before it moves on for further treatment. While the tank plays a role in managing the flow of effluent to the drain field, its primary function revolves around the treatment and storage of the influent wastewater. This makes it essential for the effective functioning of an on-site sewage management system in homes not connected to municipal sewer systems.