A septic system is an underground wastewater treatment system commonly used in rural areas where centralized sewage systems are not available. It consists of a septic tank that collects and treats household wastewater, allowing solids to settle at the bottom while liquids flow out into a drain field for further filtration. The drain field is a network of perforated pipes buried in gravel or soil, where the liquid effluent is dispersed and naturally filtered by the ground. This process helps to break down harmful bacteria and nutrients, ensuring that the treated water safely returns to the environment.