The placement of the distribution box is critical for what reason?

The placement of the distribution box is critical primarily because it must be watertight. A watertight distribution box is essential to prevent the ingress of groundwater, which could contaminate the wastewater treatment system and reduce its effectiveness. If groundwater or surface water enters the system, it can lead to overflow conditions, malfunctions, or excess loading of the treatment components, ultimately compromising the system's ability to properly treat wastewater.

While aspects like accessibility for maintenance, elevation, and dry installation conditions are important in their own right, they support the overall efficacy and operational integrity of the wastewater system but do not directly address the risks associated with leakage and contamination issues as the watertight requirement does. Ensuring that the distribution box is watertight is a fundamental aspect of safeguarding public health and the environment, as it directly contributes to the reliable operation of the entire wastewater management system.