Grease, oil and sand traps shall be provided when, in the opinion of the City, they are necessary for the protection of the sewerage system from liquid wastes containing grease in excessive amounts, or any flammable wastes, sand and other harmful ingredients; except that such traps shall not be required for buildings used solely for residential purposes. Such traps shall be required, for example, on discharges from all service stations, automotive repair garages, car washes, restaurants, eating establishments and food preparation establishments, and such other commercial or industrial establishments as the city may designate. (Ord. 2006-02 (part), 2006: Prior code § 4254)