A sanitary drainage system is a system of piping within public or private premises that conveys sewage or other liquid waste to an approved point of disposal. The intent was to design and install sanitary drainage systems that will function reliably, were neither undersized nor oversized, and are constructed from materials, fittings and connections whose quality is regulated by codes and standards.

Basic work done includes, but is not limited to, the following: public and private sewage disposal; selection of materials; installation of the building sewer, including the building drainage system and components; joining methods between drainage piping and fittings; drainage fixture units for sizing the drainage system; and sumps and ejectors.