Md. Code, Business Occupations and Professions § 12–309

(a) The Board shall reinstate the license of an individual who has failed to renew the license for any reason if the individual:

(1) applies to the Board for reinstatement within 4 years after the license expires; and

(2) meets the renewal requirements for the appropriate license under § 12-308 of this subtitle.

(b) The Board may not reinstate a journey plumber license, a master plumber license, a limited license, a propane gas fitter certificate, a master natural gas fitters license, a journeyman natural gas fitters license, or an apprentice natural gas fitters license of an individual who for any reason fails to apply for reinstatement within 4 years after the license expired unless the individual:

(1) meets the renewal requirements for the appropriate license under § 12-308 of this subtitle; and

(2) passes the appropriate examination for obtaining a license under this subtitle.