What is the primary function of a septic tank?

The primary function of a septic tank is to treat and store wastewater before it enters the drain field. In a typical septic system, wastewater from household sources flows into the septic tank, where it undergoes a separation process. The solids settle at the bottom, forming sludge, while lighter materials, such as grease and scum, float to the top. The liquid effluent that remains in the tank is then directed into the drain field, where it can be further treated by the soil.

This function is essential because it allows for the initial treatment of wastewater, reducing the amount of solid waste that could clog the drain field and ensuring that pathogens and contaminants are minimized before the effluent is distributed into the environment. Other choices present different functions that are either unrelated to the primary role of a septic tank or pertain to separate systems or processes not integrated into a traditional septic tank setup.