Missouri Plumber Career Path

Three Levels, Each With Different Authority

Missouri plumbing careers follow a three-tier progression: apprentice, journeyman, and master. Each level unlocks different work authority, and the timelines vary significantly depending on which city or county you're working in. Understanding the full path before you start prevents wasted years and missed requirements.

The critical thing to know upfront: Missouri has no statewide plumbing license. Every trade credential is issued by a local authority, so "becoming a journeyman" means becoming a journeyman in a specific jurisdiction. The steps below reflect the general pattern, with jurisdiction-specific variations called out where they matter most.

Step 1: Apprentice Registration

The apprentice phase is where you accumulate supervised field hours. Apprentice requirements are local: St. Louis County requires age 18+, a high school diploma or GED, and Board registration; Kansas City requires age 18+ and a high school diploma within an approved program.

St. Louis City and St. Louis County charge a $10 apprentice registration fee. Kansas City doesn't charge an apprentice fee — your employer tracks your hours instead. Jefferson City charges $14 for apprentice registration.

You'll work under the direct supervision of a licensed master plumber. St. Louis County enforces strict supervision ratios: the total number of apprentices at a firm cannot exceed the combined number of licensed journeymen and master plumbers. During labor shortages, masters can apply for temporary waivers allowing up to two additional apprentices with quarterly reporting.

Step 2: Apprentice to Journeyman

The hours required to qualify for the journeyman exam differ dramatically by jurisdiction:

• Kansas City: 2 years of verified experience under a licensed master
• Jefferson City: 4 years or 8,000 documented hours
• Springfield: 4 years under a master, or 6 years of general trade experience
• St. Louis City and County: 5 years of apprenticeship

St. Louis County also requires 500 hours of approved classroom training and completion of the 10-hour OSHA Safety Training for Construction course. The county offers an "Experienced Apprentice Plumber" registration for candidates who have at least two and a half years of trade employment and meet the classroom requirements.

Once your experience is documented, you sit for the applicable trade exam. Kansas City uses a 70% passing score; Springfield and Jefferson City require 75%, St. Charles County's ICC master exam requires 75%, and Jefferson County's approved ICC master exam uses a 70% minimum.

As a licensed journeyman, you can perform hands-on installation, repair, and alteration of plumbing systems without direct supervision. However, you cannot pull permits, work as an independent contractor, or contract directly with property owners. You must remain employed under a licensed plumbing contractor or master plumber.

Step 3: Journeyman to Master

The master plumber license is the highest individual trade credential in Missouri. It qualifies you to serve as a company's qualifying party; with a contractor license and the required business setup, that supports permit-pulling authority and a plumbing contracting business.

Minimum requirements to sit for the master exam:

• Kansas City: 1 year as a licensed journeyman plus two reference letters
• St. Louis County: 2 years as a licensed journeyman
• Jefferson City: 2 years as a journeyman or 12,000 total trade hours
• Springfield: 4 years as a certified journeyman, or 10 years of total trade experience
• St. Louis City: 5 years as a licensed journeyman

RSMo Chapter 341 sets a baseline of age 25 and three years of journeyman experience, but local home-rule charter cities can set their own standards. Kansas City, St. Louis County, and Columbia allow applications at age 21.

A master plumber can serve as the qualifying party (designated supervisor) for a plumbing contractor business, but only for one business entity at a time. This person assumes full responsibility for the company's code compliance and permitted work within that jurisdiction.

Step 4: Plumbing Contractor (Optional)

The contractor license is a business-level credential, not a personal trade card. It requires designating a licensed master plumber as the full-time trade supervisor, registering the business with the Missouri Secretary of State, posting any required local compliance bonds ($5,000 to $25,000 depending on jurisdiction), and carrying general liability and workers' compensation insurance.

Not every master plumber opens a business — many continue working as employees or supervisors. But the contractor license is the only path to pulling permits under your own company name and contracting directly with the public.

Map Your Progression

The Missouri Plumber License Guide lays out the full career path across seven Missouri jurisdictions with comparison tables for experience requirements, exam passing scores, and fee schedules at each level.

See more Missouri guides →