The sidewalls of a septic tank must extend above the liquid depth by how many inches?

The sidewalls of a septic tank must extend above the liquid depth by a specific minimum height to ensure proper function and maintain the integrity of the tank. A height of 9 inches is required because it provides adequate space above the liquid level to prevent overflow and allows for the operator to safely service and inspect the system. This height helps to accommodate fluctuations in liquid levels due to variations in usage and ensures that the tank remains watertight and secure against environmental conditions.

Additionally, this specification aligns with industry standards that prioritize the functionality and safety of septic tank systems. By adhering to these guidelines, you reduce risks of contamination or structural issues that could arise from improper tank levels. Choosing a height like 9 inches strikes an effective balance between functionality and safety.