Plumbing Apprentice Year 4: Course C; This is one of four 8-week courses that comprise the Year 4 Plumbing Apprentice training. This is offered by Hyflex for large groups and Online for smaller groups. Year 4 of the Plumbing Apprentice training covers commercial plumbing and code review in preparation for the state Journeyman’s exam. Subjects covered: Hydronics, solar piping, pumps, septic tanks, drain fields, and customer relations. The entire Uniform Plumbing Code is reviewed with practice exams given.