It shall be unlawful for any person to connect with the sewer system any drain or pipe which discharges rain water, cellar, basement or sump pump, or surface water, or the contents of any spring, flowing well, creek, ditch or other watercourse without a special permit from the sewer district. No boiler or heating plant shall be directly connected to the sewer system. The overflow from boilers to heating plants, when cooled to a temperature not to exceed 120 degrees Fahrenheit, will be allowed to run into a sump, said sump to be connected to the sewer. The discharge of the contents of waste pipes from water filters, gas engines, air compressors, vacuums or dry cleaners, laundries, garages, wash racks, stores or warehouses containing inflammable substances, car barns, buildings for the stabling or keeping of horses, cows and other animals, and all similar establishments shall not be made into or connected with the sewer system unless such contents are discharged into settling tanks properly trapped and vented, said tanks to be of a construction approved by the sewer district and to be at all times subject to its inspection and approval or condemnation. Upon condemnation by the sewer district, the effluent from said tanks shall not be allowed to flow into sewers until satisfactory alterations have been made and the construction approved by the sewer district. [Code 2000 § 9-5-3].