Plumbing Apprentice Year 1: Course C; This is one of four 8-week courses that comprise the Year 1 Plumbing Apprentice training. This is offered by Hyflex for large groups and Online for smaller groups. Year 1 of the Plumbing Apprentice training covers the hows and whys of plumbing theory, the Uniform Plumbing Code, Idaho Plumbing Code, residential and commercial installations, blueprint reading, estimating, job safety, plumbing repairs, and much more.