D.C. Code § 50-1109

The Mayor shall notify an owner of the expiration date of the owner’s vehicle inspection sticker. The required notice shall be mailed to the named owner at the address of record at least 30 days prior to the date of expiration. If the Director does not deliver the notice as required, the first of any tickets issued for failure to display a current inspection sticker for that inspection period may be dismissed through mail or in-person adjudication.