Free Texas Journeyman Plumber Exam Flashcards

The building drain is the lowest piping of the drainage system that receives discharge from soil, waste and other drainage pipes inside the building. It ends 30 inches of developed length beyond the exterior wall, and from that point the building sewer takes over to carry the discharge to the public sewer or other point of disposal. Knowing the 30-inch break matters because pipe materials, cleanout rules and testing differ between the two.