The top of the partition shall terminate how far below the bottom side of the tank top in order to leave space for air or gas passage between compartments?

Study for the North Carolina Septic Inspector Exam. Use detailed flashcards and multiple choice questions with hints and explanations. Get exam-ready today!

The idea is to leave a small air space at the top of the tank between the partition and the tank lid so that air and gases can move between compartments. This venting keeps gas from building up and allows the scum and liquid layers to separate properly as wastewater flows from the first to the second compartment. Two inches below the tank top provides enough clearance for this gas passage while preserving most of the tank’s liquid volume for retention. If the gap is smaller, venting is restricted and odors or pressure issues can occur; if it’s larger, you unnecessarily reduce the tank’s effective capacity without additional benefit.