What type of piping is used from a septic tank to a drain field located under paving?

The use of piping from a septic tank to a drain field is critical for ensuring proper drainage and preventing any contamination of the surrounding environment. PVC schedule 80 pipe is the correct choice for this application due to its thicker walls compared to schedule 40 pipe, which provides increased strength and durability. This characteristic is particularly important when the pipe is buried under paving, as it may be subjected to additional pressure and weight from above.

Schedule 80 PVC is designed to withstand higher levels of stress and is less likely to succumb to cracks or damage, which can occur from traffic load and soil settling. Its ability to resist corrosion also makes it suitable for use in a variety of ground conditions without risk of degradation over time.

Other options, such as CPVC, typically do not have the structural strength required for such applications, and both PVC schedule 40 and galvanized steel are less robust in situations where additional pressure is present. Galvanized steel, in particular, is prone to rust and corrosion, which can compromise the integrity of the system over time, especially in a damp environment like that around a septic system. Therefore, the choice of PVC schedule 80 pipe ensures a reliable and long-lasting solution for transporting effluent to a drain field beneath paving.