At least one copy of each primary code adopted by reference, and of each secondary code pertaining thereto, all certified to be true copies by the clerk of the legislative body, shall be filed in the office of the clerk of the legislative body at least 15 days preceding the hearing, and shall be kept there for public inspection while the ordinance is in force. However, after the adoption of the code by reference, one copy of the primary code and of each secondary code may be kept in the office of the chief enforcement officer instead of in the office of the clerk of the legislative body.