Once the excavation is complete, technicians carefully lay out the distribution pipes or chambers in the drain field trenches, ensuring even distribution of effluent throughout the area. The pipes or chambers are designed to allow the effluent to seep into the soil, where natural biological processes help filter and purify the wastewater. Proper spacing and slope of the pipes are essential to ensure efficient treatment and prevent clogging or backup within the drain field.

After the distribution system is installed, technicians backfill the trenches with suitable material to cover the pipes and promote proper drainage. Gravel or sand may be used to create a protective layer and enhance drainage capabilities. Finally, the drain field is carefully graded to ensure surface water drains away from the area, minimizing the risk of waterlogging or saturation that could compromise the system's effectiveness. A well-designed and professionally installed drain field is crucial for the long-term performance and durability of a septic system, promoting effective wastewater treatment and environmental protection.