If an impounded vehicle goes unclaimed, every state has a law requiring the impounding towing company to notify the last known registered vehicle owner and lienholder, if any, of the impound, the amount of outstanding charges, and the possibility that the vehicle will be sold if it remains unclaimed. These requirements must be met to perfect a lien, if one exists. The notice must be sent via certified mail within a specified number of days, typically five to seven days.