Journeyman Plumber: Independent Work Under Code
The journeyman plumber works independently on plumbing installations while remaining under the general supervision of a master plumber or the licensed contractor. The journeyman exam tests practical code application: proper pipe materials and fittings, drainage slope, trap and vent installation, fixture clearances, water supply sizing, and safe handling of potable water connections.
Key concepts to review include the requirement that every fixture have a trap, the prohibition on double-trapping and on trap arms exceeding allowable developed length, venting to protect trap seals, and the correct slope for horizontal drainage (commonly one-quarter inch per foot for smaller pipe sizes, with larger sizes per code tables). Journeymen must also understand protection of potable water from contamination through backflow prevention and the rules for connecting dissimilar materials.
Traps in journeyman questions include assuming a journeyman may obtain permits or contract directly with a homeowner - typically that authority rests with the licensed contractor or RMP. Another trap is treating venting as optional when a fixture is rarely used; code requires venting regardless of use frequency. Watch for questions that swap "minimum" and "maximum" dimensions, or that present a plausible slope that is actually too flat.
Rule of thumb: slope, trap, and vent questions are usually about protecting the trap seal - if a proposed installation would siphon or back-pressure a trap, it is wrong.
Worked example: A lavatory drain runs a long horizontal distance before connecting to a stack. The correct answer protects the trap seal by keeping the trap arm within the allowable length and providing a proper vent.