What is a septic tank primarily used for?

A septic tank is primarily used for collecting and treating wastewater on-site. It functions as a simple yet effective system designed for households not connected to a centralized sewer system. The tank receives wastewater from the household’s plumbing, allowing solids to settle at the bottom, where they are broken down by anaerobic bacteria. This process reduces the volume of solids and helps prevent clogs in the drainage system. The liquid effluent then flows into a drain field, where it is further treated by soil microorganisms before being released into the environment.

The primary purpose of a septic tank is to manage household wastewater, which includes sewage from toilets, sinks, and other plumbing fixtures. This on-site treatment is essential for preventing groundwater contamination and ensuring proper disposal of wastewater in rural and suburban areas. Overall, the septic tank plays a crucial role in individual wastewater management systems, making option C the correct answer.