Georgia Septic Installer Practice Test

How thick should the layer of aggregate be below the perforated pipe?

1. 2 inches

2. 4 inches

3. 6 inches

4. 8 inches

The correct answer is: 4 inches

The appropriate thickness of the layer of aggregate below the perforated pipe in a septic system is crucial for ensuring proper drainage and optimal performance of the system. A thickness of 4 inches is ideal because it provides enough space for wastewater to flow through the aggregate and enter the surrounding soil. This thickness allows for adequate permeability, ensuring that the liquid effluent can move freely while also supporting the weight of the system and preventing the pipe from settling. Using this recommended thickness helps maintain air pockets within the aggregate, promoting effective aerobic treatment of the wastewater as it percolates through the gravel. If the layer is too thin, it could lead to insufficient drainage and potential clogs. Conversely, a layer that is too thick might not provide added benefits and could make the system more complex without improving its efficiency. Thus, adhering to the established standard of 4 inches is important for the longevity and effectiveness of the septic system.