Moving to Illinois as a journeyman plumber: every state's rule
Illinois does not issue a statewide journeyman plumber license, so there is no reciprocity to speak of. Here is what that means in practice.
Illinois journeyman plumber · “No journeyman tier (Apprentice Plumber is the only sub-licence)”
No individual license at this level
Issued by Illinois Department of Public Health (IDPH), Plumbing Program
Illinois has no journeyman plumber licence. Under the Illinois Plumbing License Law (225 ILCS 320) the Department of Public Health issues a single Plumber licence plus an Apprentice Plumber licence; there is no intermediate journeyman card and no master tier, and the City of Chicago's parallel programme under Section 16 follows the same two-tier structure. Every person who performs plumbing must hold one of those two licences (Section 3(1)). An out-of-state journeyman therefore has nothing to transfer to: the choices are (1) register as an Illinois Apprentice Plumber (age 16 or older, sponsored by an Illinois licensed plumber or an approved apprenticeship programme, maximum six years as an apprentice) and work under supervision, or (2) qualify for the full Illinois Plumber licence, where Section 17(b) lets a plumber licensed by another state with substantially equal requirements sit the Illinois examination without first serving the four-year Illinois apprenticeship. Whether a journeyman-level origin licence counts as 'substantially equal' to the Illinois Plumber licence is decided by the State Board of Plumbing Examiners case by case and is not addressed on the IDPH page reviewed; see the master level for the licence route.