Missouri to Idaho: journeyman plumber license reciprocity

How local licensing works. Missouri regulates plumbers only through local government. RSMo §§ 341.010-341.080 (cities over 15,000) require plumbers to hold a certificate issued after examination by a city board of examiners, and §§ 341.090-341.220 (first-classification counties) let a county create a department and board of plumbing and sewer inspection that licenses master plumbers, journeymen and drainlayers, sets fees and license terms (§ 341.180) and requires master plumber bonds (§ 341.200). Each board writes its own rules, so hours, exams, fees and the treatment of other jurisdictions' licenses differ from place to place, and a plumber must hold the license of each jurisdiction in which they work.

St. Louis County. The Department of Transportation and Public Works' Plumbing Licensing office (41 South Central Avenue, Clayton, 314-615-3741, [email protected]) licenses Journeyman, Master Plumber and Apprentice plumbers and certifies plumbing contractors under the county plumbing code. The Board of Plumbing Examiners normally meets the first Thursday of each month at 8:00 a.m., and renewal carries a PEU (professional education unit) requirement. The county's separate mechanical board exempts pipefitting and sprinkler-fitting journeymen 'licensed under the county plumbing code' from its own test, which shows how tightly the county's trade licenses are tied to its own code.

City of St. Louis. The Building Division's Plumbers and Drainlayers Board of Examiners 'reviews licensing matters, apprentice applications, complaints, and other business related to plumbing and drainlaying work in the City of St. Louis'. Certification requires an application with notarized references and a passing score from a recognized agency such as Prometric or ICC ($60 application, first four-year certificate free, $181 renewal every four years), and the city 'may accept comparable examinations from other jurisdictions if deemed equivalent or superior' to its approved exams. Whether Kansas City still issues a separately titled journeyman plumber license, its experience requirement and any named reciprocity (for example with Johnson County, Kansas) could not be confirmed because kcmo.gov, the proxy and the archive were all blocked on 2026-09-16.

Springfield. Building Development Services certifies Journeyman Plumbers. Eligibility is 4 years under the supervision of a master plumber or 6 years' experience in the trade, documented on signed, notarized Applicant Experience Forms for every employer (Schedule C or 1099s if self-employed). The packet goes to the board, which meets the first Thursday of each month at 5:00 p.m. in the Busch Building; approval to test is good for one year. The exam is the ICC plumbing exam through Pearson Vue (about $125 paid to Pearson Vue), 75% to pass; the city then issues the Trade Certification Card for $25, renewing at $25 per year. Out-of-state treatment: an applicant licensed in another jurisdiction applies under 'Reciprocity from another jurisdiction' by submitting the same experience documentation plus a copy of an exam score notification of 75% or better from Prometric, Experior, Block or ICC (Pearson Vue), 'the examination must be the identical exam as required by the City of Springfield'; the exam is then not repeated. A license backed by a different exam gives no advantage beyond documenting experience.

Columbia and others. Columbia, St.