The invert of the outlet tee must be located how many inches below the inlet tee?

The correct position of the invert of the outlet tee being two inches below the inlet tee is essential for ensuring proper gravity flow within the septic system. This two-inch drop helps to maintain adequate slope for wastewater to flow effectively from the inlet side into the outlet side.

A differential between the inlet and outlet levels is crucial to minimize the risk of wastewater backing up into the system, which can lead to inefficiencies and potential system failure. By maintaining this two-inch separation, the system promotes effective drainage and prevents issues such as clogging, slow drainage, or even backflow, which could compromise the overall functionality of the septic system.

This positioning is also aligned with best practices and some local or state regulations that dictate septic system installations, reflecting an understanding of how gravity plays a vital role in wastewater management.