For the purpose of this subchapter, the following definitions shall apply unless the context clearly indicates or requires a different meaning.
BUILDING DRAIN. Part of the building drainage system which receives the discharge from soil, wastes and other drainage pipes inside the walls of any building and conveys the same to the building sewer.
BUILDING SEWER. Part of the horizontal portion of the building drainage system, extending from the building drain to its connection with the septic tank and carrying the sewage out of the building.
INDIVIDUAL SEWAGE TREATMENT SYSTEM. A sewage disposal system, other than a public or community system, which receives sewage from an individual establishment. Unless otherwise indicated, the word “system” as it appears in this subchapter means INDIVIDUAL SEWAGE TREATMENT SYSTEM.
SEWAGE. Any water-carried domestic waste, exclusive of footing and roof drainage, of any residence, industry or commercial establishment, whether treated or untreated, and includes the liquid wastes produced by bathing, laundry and culinary operations, and from toilets and floor drains. Raw sewage is SEWAGE which has not been subjected to any treatment process.
(’77 Code, § 404.01)