The Hattiesburg American reports that Lamar County supervisors voted 5-0 to update an ordinance that's been on the books since 1997.
Supervisor Phillip Carlisle says he recently saw a fire truck make a U-turn because it couldn't find the correct driveway for a smoking house. He says a mailbox with an address number would have helped.
Violators could be fined $50 a day, but county Administrator Jody Waits says the goal is to get people to post house numbers.
Numbers must be reflective and 3 inches or larger. Homeowners can order green address signs from their local fire department.