What is the main purpose of a septic tank?

The main purpose of a septic tank is to treat and store sewage. Septic tanks are designed to receive wastewater from household plumbing, separating solids from liquids and providing initial treatment of the sewage. Inside the tank, solids settle to the bottom, forming sludge, while lighter materials, such as grease, float to the top, creating a scum layer. The liquid effluent then flows out of the tank into the drain field, where further treatment and disposal occur through soil filtration.

Understanding the function of a septic tank is crucial for effective wastewater management, particularly in areas lacking centralized sewer systems. The treatment process ensures that harmful pathogens and organic matter are broken down before the treated wastewater reenters the environment. This process also helps prevent groundwater contamination and protects public health.