Massachusetts Plumbers Journeyman Practice Exam 2026 – All-in-One Guide to Master Your Licensing Test!

An automatic trap-priming device for floor/trough drains serves the purpose of maintaining the water seal in the trap. The water seal in a trap prevents sewer gases from entering the building, acting as a barrier between the plumbing system and the indoor environment. By automatically adding water to the trap when needed, the device ensures that the seal remains intact, thus protecting the occupants from potentially harmful sewer gases.