How much experience as a plumber trainee — including a minimum commercial/industrial component — is generally required before a candidate is eligible to sit for the Washington journeyman plumber exam?
Not quite. The answer is D: 8,000+ hours total, including 4,000+ hours commercial/industrial
Washington requires at least four years and 8,000 hours of documented trainee experience under a certified journey-level plumber, and half of that — at least 4,000 hours — has to be commercial or industrial work, so a candidate cannot qualify on residential-only experience. The 2,000-hour figure is the first-year direct-supervision requirement for a different certificate (residential service), which is the usual source of the mix-up.
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