Upon notification by the Director of Public Service of the proper number for a house or building, the owner of such house or building shall cause such number to be placed on the front of the house or building. If a house or building stands back more than fifty feet from the street line, the numbers shall be displayed conspicuously at or near the walk or driveway in an appropriate place so as to be easily legible from the sidewalk. Such numbers shall not be less than three inches in height. (Ord. 58-15. Passed 9-2-58.)