What is the minimum requirement for the number of holes in a four-inch diameter or larger pipe?

The minimum requirement for the number of holes in a four-inch diameter or larger pipe is at least two rows of holes. This specification is crucial for ensuring adequate drainage and proper function of the septic system. The two rows allow for efficient water flow and prevent clogging, as they increase the surface area available for effluent to exit the pipe. It also helps maintain good aeration within the drainage system, which is essential for the breakdown of waste.

In septic system design, sufficient perforations prevent the buildup of pressure and facilitate the movement of liquids in the wastewater treatment process. Having only one row of holes would not provide enough drainage capability. More than two rows may not be necessary and could lead to excess cost and potential structural weakness in the pipe. Thus, requiring a minimum of two rows strikes a balance between functionality and efficiency.