Minnesota Master Plumber License

What the Master License Actually Unlocks

A Minnesota journeyman can perform plumbing work statewide, but they can't pull permits, bid on projects independently, or operate a contracting business. The master plumber license changes that. It's the only individual credential that authorizes:

• Pulling plumbing permits (when designated as RLI for a licensed contractor)
• Supervising registered unlicensed plumbers and journeymen
• Designing, planning, and superintending complex plumbing systems
• Serving as the Responsible Licensed Individual for a plumbing contractor company

Without a master on staff, a plumbing business cannot hold a contractor license in Minnesota.

Eligibility Requirements

The path to master requires an active Minnesota journeyman license plus at least one year (1,750 hours) of documented practical experience gained while holding that journeyman credential. The same 1,750-hour annual cap that applies to apprentices applies here — you can't compress the year by working more hours.

Alternative eligibility routes exist but they're narrow:

• Holding an equivalent master plumber license from another state with exam-based licensing standards comparable to Minnesota's
• Holding an active Minnesota restricted master plumber license plus five years of verified experience as an active plumbing contractor

For most people, the standard path is the realistic one: earn your journeyman, work at least one full year as a licensed journeyman, then apply.

The Master Exam

The exam application goes through the DLI iMS portal with a $50 fee. Once DLI approves your application (verifying your journeyman experience), you schedule through Prometric.

The master exam has 100 multiple-choice questions with a 4-hour time limit. It covers everything on the journeyman exam — water supply sizing, drainage, venting, code navigation — plus advanced topics: isometric drawing analysis, complex plan review, water supply system design, and regulatory compliance.

Closed-book format. The testing center provides reference sheets, sizing tables, and a calculator. You need a 70% to pass, and results come immediately. If you fail, there's a mandatory 30-day wait and another $50 fee before you can retake.

Costs and Timeline

Master licenses expire biennially on December 31 of even-numbered years (journeyman licenses expire in odd-numbered years — the offset is intentional). Renewal requires 16 hours of DLI-approved continuing education: at least eight hours covering the Minnesota Plumbing Code and eight hours on technical or statutory topics.

The Fast Track to Running a Business

Getting your master license is necessary but not sufficient for starting a plumbing company. The contractor license adds business requirements: entity registration with the Secretary of State, a $25,000 surety bond, general liability insurance, workers' comp coverage or a validated statutory exemption if the business has no employees, and a $188 licensing fee. The master you designate as RLI must be a W-2 employee, owner, officer, or member of the company.

The Minnesota Plumber License Guide maps the complete journeyman-to-master-to-contractor sequence, including the exact insurance and bond specifications that trip up first-time applicants.

See more Minnesota guides →