When the Building Inspector shall so designate the numbering of any houses or buildings in the City, he shall give written notice thereof to the owner of any building whose number shall be required to be changed, and it shall be the duty of such owner, within thirty days of receipt of such notice, to change the number upon such building as required by such notice, or to remove the number from such building. The Inspector, upon application to him therefor, shall furnish to the owner therof, the proper number for any building within the City, when the same has been fixed by him as herein provided. (1970 Code Sec. 6-17)