What is a Dispersal Zone?

• A. The area of the building where wastewater is treated.
• B. Dimensional volume of insitu soil that receives wastewater for treatment or distributes final effluent for disposal.
• C. A stationary point used for vertical measurements.
• D. A device that screens debris before entering the septic system.

Answer: (B)

The dispersal zone is the volume of in-situ soil that receives wastewater for treatment or distributes final effluent for disposal. In a septic system, after solids settle in the tank, the liquid effluent moves into this soil area—often the drain field or absorption bed—where it percolates through the soil. The soil and its micro biology then filter and partly treat the wastewater as it percolates, helping protect groundwater by removing solids, bacteria, and other contaminants. This zone is defined by the size and depth of the soil absorption area designed for the flow, soil type, and percolation rate.

It's not the area inside the building where wastewater is treated (that’s the pretreatment/tank area), not a fixed vertical measurement point, and not a device that screens debris before entering the system.