Missouri to Idaho: master plumber license reciprocity

How local licensing works. There is no state plumbing board. Under RSMo chapter 341, city boards of examiners (cities over 15,000) and county boards of plumbing and sewer inspection (first-classification counties) examine master plumbers; § 341.170 sets the county master plumber qualifications, § 341.180 the application fees, license terms and re-examination rules, and § 341.200 requires master plumbers and master drainlayers to post surety bonds. The master license is the credential that lets a plumber pull permits and run a plumbing business, and each jurisdiction issues and enforces its own.

St. Louis County. The Plumbing Licensing office (41 South Central Avenue, Clayton, 314-615-3741) issues Master Plumber licenses and publishes a Certified Contractors list; the Board of Plumbing Examiners meets the first Thursday of each month at 8:00 a.m., and renewals carry PEU continuing-education requirements. Louis.** The Building Division's Plumbers and Drainlayers Board of Examiners licenses master plumbers and drainlayers and reviews licensing matters and complaints for plumbing and drainlaying work in the city; permits are issued to city-licensed contractors. Every licensed contractor must employ a full-time supervisor who holds a Kansas City certificate of qualification in the plumbing trade, obtained on 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); the city 'may accept comparable examinations from other jurisdictions if deemed equivalent or superior'. Whether a separately titled master plumber license, plumbing-specific experience hours or named reciprocity with Kansas jurisdictions exist could not be confirmed because kcmo.gov and both fallback routes were blocked on 2026-09-16.

Springfield. Building Development Services certifies Master Plumbers: 4 years as a certified journeyman plumber or 10 years of satisfactory experience in the trade, documented on notarized employer experience forms and approved by the board (first Thursday monthly, 5:00 p.m., Busch Building; approval to test good for one year). The exam is the ICC master plumber exam through Pearson Vue (about $125 paid to Pearson Vue), 75% to pass; the certification card costs $50 with $50 annual renewal, and a master must file a Master Registration form to qualify a contracting business (Master Resignation form on leaving). Out-of-state treatment: 'Reciprocity from another jurisdiction' applicants submit the same experience documentation plus an exam score notification of 75% or better from Prometric, Experior, Block or ICC (Pearson Vue) for the identical exam Springfield requires; otherwise they test. Springfield also certifies Master Gas fitters (4 years as a certified gas journeyman, or 4 years as a master mechanic or plumber plus 2 years as a gas journeyman).

Columbia and others. Columbia, St.