What is the primary function of a septic tank?

The primary function of a septic tank is to treat and dispose of wastewater from homes and buildings. Septic tanks are part of a decentralized sewage treatment system, typically used in areas not connected to a centralized sewer system.

When wastewater flows into the septic tank, it undergoes a natural treatment process. Solids settle to the bottom, forming a sludge layer, while lighter materials like fats and oils float to the top, creating a scum layer. The bacteria within the tank break down organic matter, leading to a degree of treatment before the effluent is released into a drainage field or leach field for further treatment in the soil. This two-step process—initial treatment in the tank and subsequent leaching into the ground—is essential for effectively managing wastewater and protecting public health and the environment.

In contrast, storing solid waste, although part of the tank's function, does not encompass the full scope of its purpose, which also involves treating the wastewater. Preventing flooding in urban areas and filtering drinking water are unrelated to the function of a septic tank and involve different systems and approaches altogether.