The "plumbing system" of a building means and includes the water supply distributing pipes; fixture traps; soil, waste and vent pipes; building drain and building sewer, and storm water drainage, with their devices, appurtenances and connections, all within or adjacent to the building. The "drainage system" means that part of the plumbing system exclusive of the water supply and distributing pipes.
(1957 Code §1123.06)