All nondomestic users, shall be required to install and maintain a grease, oil and sand interceptor. It is necessary for the proper handling of (a) liquid waste containing grease, (b) flammable wastes, (c) sand, or (d) other harmful constituents which may be properly eliminated from the sewerage system by the use of an interceptor or trap. Interceptor is not required for a building used solely for residential purposes as long as there is no common food preparation facility. Interceptor is required when the wastewater flow from the building is anticipated to contain grease, flammable substances, sand or other harmful ingredients in amounts or concentrations which in the opinion of the city present the possibility of causing or contributing to the fouling of or the blockage of or other damage to the city facilities. (Ord. 01-102 § 2(part), 2001).