For molded plastic distribution boxes, how many inches should the invert of the outlets be?

The correct answer identifies that the invert of the outlets in molded plastic distribution boxes should be below the invert inlet. This configuration is essential for ensuring proper flow and drainage within a septic system. When the outlet invert is positioned below the invert inlet, it facilitates gravity-driven drainage. This alignment allows wastewater to flow smoothly from the inlet to the outlets, minimizing the risk of backups or pooling within the distribution box.

Maintaining this relationship between the inlet and outlet helps optimize the performance of the septic system by promoting even distribution of effluent to the downstream components, such as the drain field. This design principle is crucial for preventing overloading and ensuring that the septic system operates efficiently and effectively for waste treatment.