Inspect the box's construction, looking for any visible cracks, signs of deterioration, or points of pipe misalignment, which could allow soil or roots to infiltrate the system. If the visual inspection reveals minor issues, several immediate remediation steps can be taken to. A septic distribution box, often called a D-box, is a small, buried container that acts as a junction point between the septic tank and the soil absorption area. This component receives partially treated liquid waste, known as effluent, from the septic tank's outlet pipe. When it fails, symptoms include uneven wet spots in the yard, slow indoor drains, and sewage odors.