What is the primary function of a drainfield in a private septic system?

The primary function of a drainfield in a private septic system is to treat and disperse wastewater. When wastewater exits the septic tank, it flows into the drainfield, which consists of trenches filled with gravel or other natural material. This design allows for the wastewater to be distributed evenly across the land, where the soil plays a critical role in filtering and treating the effluent.

Soil microorganisms break down harmful pathogens and nutrients in the wastewater, leading to a more environmentally safe discharge into the ground. This process ensures that the treated water can percolate down into the groundwater or be absorbed by plants, effectively returning it to the water cycle while minimizing environmental hazards.

The other options do not reflect the specific role of a drainfield. While stormwater management may involve drainage systems, the drainfield is specifically intended for wastewater. Similarly, the septic tank is responsible for storing sludge, while the drainfield does not serve that purpose. The point about acting as foundation support is unrelated, as a drainfield is designed for wastewater treatment rather than structural support.