Which of the following best describes the function of a septic system?

The primary function of a septic system is to treat and dispose of household wastewater. This system is designed to safely process the effluent that comes from domestic activities, such as bathing, cooking, and sanitation. When wastewater enters the septic tank, solids settle to the bottom, where they decompose, while the liquid effluent flows into a drain field for further treatment and absorption into the soil. This process helps to protect public health and the environment by ensuring that harmful pathogens and contaminants are adequately broken down and contained.

The other choices do not accurately represent the core function of a septic system. Providing drinking water is the role of a water supply system, managing stormwater runoff typically involves different infrastructure like drainage systems, and processing agricultural waste is associated with specialized facilities called waste treatment systems for agriculture, rather than a conventional septic system.