Septic License Practice Exam 2025 - Free Septic License Practice Questions and Study Guide

The primary purpose of the leach field in a septic system is to treat effluent before it enters groundwater. After sewage and wastewater flow from the home into the septic tank, solids settle to the bottom while the liquid effluent is then directed to the leach field.

The leach field consists of a series of perforated pipes laid in gravel or soil, allowing the effluent to percolate through the soil. As the effluent passes through the soil, natural biological processes break down harmful pathogens and chemicals, effectively treating the wastewater before it reaches the groundwater. This process of filtration and absorption is crucial in preventing contamination of drinking water sources and maintaining environmental health.

Other functions related to the septic system, such as breathing for the septic tank, storing solids, or maintenance space, are not the primary roles of the leach field. Instead, they pertain to different components of the septic system or to its operational aspects. Thus, the leach field's primary role remains centered on the treatment of effluent.