What is the primary function of a filter in a septic system?

The primary function of a filter in a septic system is to remove solids from effluent before it enters the drain field. This step is crucial for ensuring that only treated liquid waste is distributed into the drain field, thus protecting the environment and preventing clogging in the drain field, which could lead to system failure.

Filters serve to catch floating solids and prevent them from moving through the system. By doing so, they improve the overall efficiency of the septic system by allowing for better absorption and treatment of wastewater in the drain field. This process is vital for maintaining the longevity of the entire septic system and minimizing the risk of groundwater contamination.

The other choices, while they describe functions related to a septic system, do not accurately reflect the primary role of a filter. Maintaining water levels, preventing chemicals from entering, and aerating liquids are important aspects of septic system operation but do not pertain directly to the filtering process and its specific purpose.