What is the minimum pipe diameter from the house to the tank?

The minimum pipe diameter from the house to the septic tank is indeed 3 inches. This size is crucial for ensuring proper gravity flow of wastewater from the house to the tank. A pipe diameter of 3 inches is generally considered optimal for residential applications because it can handle typical household wastewater flow and minimize the risk of clogs. This diameter supports adequate capacity to transport solid waste and wastewater effectively without causing backups.

Larger diameters, such as 4 inches or more, could be used in specific scenarios for larger systems or heavier flow requirements but are not necessary for standard residential installations. A diameter of 2 inches, on the other hand, would be insufficient in most cases, as it may not accommodate the flow rates and solids encountered in domestic sewage systems, increasing the likelihood of blockages or backflow issues. Therefore, 3 inches strikes a balance between efficient waste movement and practical installation for typical residential uses.