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In the state of Minnesota, you must obtain a plumbing license from the Minnesota Department of Labor and Industry (DLI) Construction Codes and Licensing Division in order to legally work as a professional plumber. To obtain this license, you must meet several requirements.

Types of Plumbing Licenses in Minnesota

There are three types of plumbing licenses, each with its own requirements and benefits. Typically, you’ll start with a journeyworker plumbing license before obtaining a master plumbing license and then a plumbing contractor license.

Journeyworker Plumber

As a licensed journeyworker plumber, you must work under the supervision of a master plumber. In this capacity, you are permitted to work throughout the state and may perform work on interior plumbing and exterior water systems, as well as sanitary and storm sewer systems.

Before you can become a journeyworker plumber, you must register as an unlicensed plumber with the DLI and obtain four years of practical plumbing experience. Alternatively, you could complete an equivalent DLI-registered apprenticeship program.

If you currently hold a restricted journeyworker or master plumber license, you will only need two years of additional work experience to qualify. Professionals with an out-of-state license may also qualify if that license required you to complete four years of work experience.

To apply, you submit a completed, signed, and notarized application, and you must pass the journeyworker plumbing exam. This open-book test has 240 questions covering the following topics:

• Basic principles of plumbing
• Codes and regulations
• Essential definitions
• Fixtures and fittings
• Water heating systems
• Water supply and distribution
• Drainage and sanitation
• Indirect waste
• Ventilation
• Inceptors and traps
• Storm drains

You will have 5.5 hours to complete the test and must answer at least 168 questions (70%) correctly to pass.

Master Plumber

As a master plumber, you may do everything a journeyworker does, as well as the planning, oversight, and installation of plumbing systems. You may also supervise journeyworker plumbers.

Before you can become a master plumber, you must complete one year of experience as a journeyworker. Professionals with a restricted master plumber license and five years of verifiable experience will also qualify, as will those with an out-of-state master plumber license featuring equivalent requirements.

Once these criteria are met, you can submit your completed, signed, and notarized application and take the master plumbing exam. This open-book test consists of 335 questions covering the same topics as the journeyworker exam. You will have 5.5 hours to complete the test and must answer a minimum of 235 questions (70%) correctly to pass.

Plumbing Contractor

No additional testing is required to become a plumbing contractor, but you must register with the Minnesota Secretary of State/Assumed Name Verification, as well as disclose business owners, partners, officers, and members of your company. You must also provide several documents, including:

• Proof of surety bonds
• General liability insurance policies
• Workers’ compensation insurance policies
• Unemployment compensation
• Certificate of responsible licensed individual
• Completed, signed, and notarized application

With this license, you may contract to perform plumbing work, provided you have a licensed master plumber as a responsible licensed individual and you comply with all state requirements.

If you’re ready to obtain your journeyworker, master, or contract plumbing license in Minnesota, RocketCert can help you prepare for exams. Contact us today to get started.