For the purpose of this subchapter, the following definition shall apply unless the context clearly indicates or requires a different meaning.
   NORMAL DOMESTIC SEWAGE. Wastewater discharged to the wastewater facilities of the city where the concentration of 5-day, 20ºCentigrade biochemical oxygen demand (B.O.D.) does not exceed 200 milligrams per liter (mg/l) and the concentration of suspended solids (SS) does not exceed 250 mg/l.