In terms of septic tanks, what does "freeboard" mean?

Freeboard refers to the air space above the liquid in a septic tank. This area is crucial for several reasons. It accommodates fluctuations in liquid levels due to inflow and outflow, preventing spills and allowing for adequate gas venting, which is essential for the biological processes occurring within the tank. Additionally, the presence of freeboard helps to reduce the risk of scum and floating materials from overflowing the tank, ensuring that the septic system functions properly and remains effective in treating wastewater. Understanding the significance of freeboard is essential for proper septic tank design and maintenance, as it directly impacts the efficiency and safety of the septic system.