Except for those uses which were existing prior to January 29, 1964, auto trailers shall not be used as a permanent place of abode or as a permanent dwelling or for indefinite periods of time in the city. Those uses which existed prior to January 29, 1964, shall be connected with the city water supply and sanitary sewage system and located in compliance with all requirements of the building, plumbing, sanitary, health and electrical requirements of this Code and other ordinances of the city, and shall not be inhabited by a greater number of occupants than for which it was designated; provided, that permits shall be properly secured as required in such building, plumbing, sanitary, electrical and health requirements and ordinances.