How many inches of gravel must be placed beneath the distribution pipe in a trench?

The requirement for placing gravel underneath the distribution pipe in a trench is based on proper drainage and filtration to ensure the effective functioning of a septic system. A minimum of 6 inches of gravel beneath the distribution pipe helps to facilitate optimal effluent infiltration into the soil, promote adequate aeration, and protect the distribution system from clogging. This thickness allows for sufficient space for water flow while also providing a stable base for the pipe itself. The choice of 6 inches aligns with standard best practices in septic system installation, ensuring the longevity and efficiency of the system.