Postage $aver rejects any zip codes that do not have five digits, nine digits, or five digits followed by a dash followed by four digits, or whose first three digits do not match a listing on the USPS list of three-digit zip code areas. The mailer can also choose to have Postage $aver reject (or flag without rejecting) any zip code that does not match its accompanying state or city. All rejected and flagged zip codes are included in a "Rejected and Questionable Zip Codes" list at the end of this report.