Missouri Plumber Exam Requirements

No Single Exam Covers the Whole State

Missouri's decentralized licensing means there is no single plumbing exam that works everywhere. Each jurisdiction picks its own testing vendor, sets its own passing score, and tests on its own adopted code edition. Before you book anything, contact the specific board where you plan to get licensed and confirm the current exam requirements.

Exam Vendors by Jurisdiction

The ICC G28 (Journeyman Plumber with Gas) and G27 (Master Plumber with Gas) cover the International Plumbing Code and International Fuel Gas Code. Acceptance depends on the local jurisdiction.

Pre-Authorization Requirements

Not every jurisdiction lets you walk in and register:

• Springfield requires candidates to submit an application and experience forms to the local board, which meets on the first Thursday of every month. Once approved, the testing authorization is valid for one year.
• St. Charles County does not require pre-authorization — you can register for the ICC exam directly and submit your score afterward.
• St. Louis County uses a board-approved IAPMO exam with written and practical components; confirm the board's approval and scheduling process before booking.

What the Exams Cover

ICC exams (used by most IPC jurisdictions) test knowledge of the International Plumbing Code and, for gas endorsements, the International Fuel Gas Code. The reference code edition depends on jurisdiction — St. Charles County tests on the 2018 or 2015 IPC, while other jurisdictions may use different editions or local codes. Confirm the exact code year before you start studying.

IAPMO exams (St. Louis County) include both a written component and a hands-on practical where candidates demonstrate installation and testing procedures in person.

St. Louis City's proprietary exam is written and administered by the Board of Examiners of Plumbers and Drainlayers. The content reflects the City's own plumbing code.

Exam Fees

ICC exams through Pearson VUE typically cost $120–$150. St. Louis County's IAPMO exams are more expensive and rising:

After You Pass

Submit your score report directly to the local building division or plumbing board. They issue the trade card once your experience documentation, fees, and any additional requirements (background checks, reference letters) are complete. The trade card is jurisdiction-specific — passing the exam does not automatically license you anywhere else, though some jurisdictions accept scores from other boards on a case-by-case basis.

Retakes

If you fail, retake policies vary. St. Charles County may require re-testing with the ICC if your license has been expired for two or more code cycles (six years). Other jurisdictions' retake policies and waiting periods vary, so confirm the current rule with the board.

The Missouri Plumber License Guide includes a complete exam mapping table and study resource list organized by jurisdiction and code edition.

See more Missouri guides →