Maryland Code, Business Occupations and Professions § 12-308.1

(a) Except as provided in subsection (b) of this section, for an apprentice plumber or apprentice natural gas fitter issued an initial license on or after October 1, 2012, the Board may not renew the license for more than three consecutive terms if the licensee has not taken or registered to take a journey plumber examination or journeyman gas fitters examination.

(b) Notwithstanding subsection (a) of this section, if an apprentice plumber or apprentice natural gas fitter fails a journey plumber examination or journeyman gas fitters examination, the Board shall renew the apprentice plumber license or apprentice natural gas fitters license for an additional 2-year term for each failed examination.