- What Is A MI-MP, Exactly?
- Who Issues the Michigan Master Plumber License
- Exam Format: 130 Questions, 180 Minutes
- The Drawing-Based Material Takeoff Section
- The Eleven MI-MP Domains
- Eligibility and the 4,000-Hour Rule
- Registration, Fees, and Retakes
- Open-Book Rules: What You Can and Can't Bring
- Who Holds a Master Plumber License in Michigan
- A Domain-Aware Approach to Preparing
- Renewal and Ongoing Requirements
- Frequently Asked Questions
- MI-MP is the Michigan Master Plumber License Exam, administered by PSI Services LLC for LARA's Bureau of Construction Codes.
- The exam has 130 questions in 180 minutes and requires a 75% passing score.
- Candidates need 4,000 hours as a journey plumber over at least two consecutive years with no licensure lapse.
- The PSI exam fee is $100 per attempt, including every retake.
What Is A MI-MP, Exactly?
"MI-MP" refers to the Michigan Master Plumber License Exam - the state credentialing test that journey plumbers must pass to be licensed as master plumbers in Michigan. This is not a generic industry designation; it is a specific, state-regulated examination tied to a specific license issued by the Michigan Department of Licensing and Regulatory Affairs (LARA), Bureau of Construction Codes. If you've searched for "what is a MI-MP" because you've seen the acronym used elsewhere for something entirely different, set that aside - on this site, and in this article, MI-MP means one thing only: the Michigan Master Plumber License Exam.
Passing the MI-MP exam is the gatekeeping step between working as a licensed journey plumber and becoming a licensed master plumber in Michigan - a designation that carries more authority, more responsibility, and typically more earning potential. For a deeper breakdown of what the credential actually represents and how it's structured, see MI-MP Certification and What Is MI-MP Certification?.
Who Issues the Michigan Master Plumber License
The Master Plumber License itself is issued by LARA's Bureau of Construction Codes after a candidate meets eligibility requirements and passes the exam. The actual test-day experience, however, is managed by PSI Services LLC, the third-party testing provider that runs the computer-administered examination at test centers and, as of February 11, 2026, through remote-proctored delivery as well. PSI publishes the official candidate bulletin that governs scheduling, references allowed, and testing rules - the current version effective April 29, 2026 lists the 2021 Plumbing Code Book as the exam's primary reference.
It's worth noting that a Master Plumber License is a distinct credential from a plumbing contractor license. They serve different purposes under Michigan's licensing structure, and confusing the two is a common mistake among candidates researching requirements. If you're mapping out eligibility before you register, review MI-MP Requirements 2026: Eligibility, Prerequisites & How to Qualify for the full breakdown.
Exam Format: 130 Questions, 180 Minutes
The MI-MP exam is computer-administered, consisting of 130 questions to be completed in 180 minutes. A candidate needs a minimum passing score of 75% to earn the license. There's no partial credit strategy to game here - the format rewards broad, working knowledge of the 2021 Plumbing Code Book across all tested domains rather than deep expertise in just one or two areas.
Time management matters. With 130 questions spread across 180 minutes, candidates average under a minute and a half per question - tighter when you factor in the drawing-based takeoff section, which typically demands more sustained thinking than a standard multiple-choice item. For a detailed sense of how challenging this pacing actually is in practice, see How Hard Is the MI-MP Exam? Complete Difficulty Guide 2026.
Key Takeaway
Budget your practice sessions around realistic timing - 180 minutes for 130 questions plus a multi-step material takeoff - rather than treating question count alone as the benchmark.
The Drawing-Based Material Takeoff Section
One of the most distinctive features of the MI-MP exam is its drawing-based material takeoff component. Candidates work from a floor plan depicting back-to-back restrooms and must determine:
- Fitting quantities required to complete the installation as drawn
- Drain and vent sizing based on fixture units and layout
- Appropriate venting methods for the configuration shown
This isn't a theoretical exercise - it mirrors the kind of plan-reading and material estimating a working master plumber does regularly on the job. Candidates who've only studied code text in isolation, without practicing actual takeoffs from drawings, are frequently caught off guard by this section. Because it blends multiple domains (drainage, venting, general knowledge) into a single applied task, it deserves dedicated practice time separate from straight code-recall review.
The Eleven MI-MP Domains
PSI's candidate bulletin organizes the exam content into eleven domains. Understanding what falls under each one helps you target your review instead of re-reading the code book cover to cover.
Domain 1: Drainage Systems
Sizing, slope, cleanouts, and layout requirements for sanitary drainage.
- Fixture unit tables and pipe sizing charts
Domain 2: General Knowledge
Foundational code definitions, permitting concepts, and administrative provisions plumbers are expected to know broadly.
Domain 3: Fixtures
Fixture requirements, minimum fixture counts, and installation clearances.
Domain 4: Water Distribution
Supply pipe sizing, materials, and water service requirements.
Domain 5: Backflow Protection
Cross-connection control devices and where backflow prevention is required.
Domain 6: Storm Drains
Storm drainage system sizing and discharge requirements.
Domain 7: Special Waste
Handling of waste requiring treatment before discharge into the sanitary system.
Domain 8: Testing
Required system tests before approval, including pressure and water tests.
Domain 9: Inspections
What inspectors check at each stage of a plumbing installation.
Domain 10: Venting
Vent sizing, methods, and how venting interacts with drainage design - directly relevant to the material takeoff.
Domain 11: Skilled Trades Regulation Act, 2016 PA 407
Statutory knowledge of the act governing skilled trades licensure in Michigan, supplied onscreen during the exam.
For a domain-by-domain study breakdown with more detail on weighting and question style, see MI-MP Exam Domains 2026: Complete Guide to All 11 Content Areas.
Eligibility and the 4,000-Hour Rule
Before you can even schedule the MI-MP exam, LARA requires that you:
- Be at least 18 years old
- Have accumulated 4,000 hours working as a journey plumber
- Have earned those hours over at least the two years immediately preceding your application
- Have had no lapse in journey licensure during that two-year period
- Receive LARA approval before scheduling with PSI
This eligibility structure means the MI-MP exam isn't something you can prep for and sit on a whim - it's the culmination of documented field experience. If you're unsure whether your work history qualifies, walk through the full eligibility rules in MI-MP Requirements 2026: Eligibility, Prerequisites & How to Qualify before investing study time.
Registration, Fees, and Retakes
Once LARA approves your application, PSI handles scheduling and testing. The exam fee is $100 per attempt - and importantly, that fee applies to every retake, not just your first sitting. There's no discounted retake rate, so failing on your first attempt is a real cost, not just a delay.
This fee structure makes first-attempt preparation financially meaningful. A full cost breakdown, including how the $100 PSI fee fits alongside licensing and renewal costs, is available in MI-MP Certification Cost 2026: Complete Pricing Breakdown.
| Item | Detail |
|---|---|
| Exam fee (per attempt, incl. retakes) | $100 |
| Question count | 130 questions |
| Time allowed | 180 minutes |
| Minimum passing score | 75% |
| Master license renewal fee | $300 every three years, due April 30 |
Open-Book Rules: What You Can and Can't Bring
The MI-MP exam is open book, but the rules are strict. Candidates may bring a bound code book with chapter tabs - nothing more. That means:
- No additional loose papers or handwritten notes
- No highlighting, underlining, or indexing added to the code book during the exam
- No personal calculators inside the test room - PSI test-center security rules require calculators to be stored outside
The State Construction Code Act, 1972 PA 230, and the Skilled Trades Regulation Act, 2016 PA 407, are supplied onscreen during the exam - personal paper copies of either statute are prohibited. This matters directly for Domain 11, since you'll need to navigate the onscreen statute rather than a tabbed personal copy.
Who Holds a Master Plumber License in Michigan
Master plumbers in Michigan typically supervise journey and apprentice plumbers, take on more complex system design responsibility, and - depending on business structure - may be positioned to run or oversee plumbing operations. Employers ranging from mechanical contractors to municipal utilities look for the master designation when filling supervisory and design-oversight roles. If you're evaluating how this credential affects job prospects and pay, see MI-MP Jobs and MI-MP Salary Guide 2026: Complete Earnings Analysis. For a broader look at whether the investment of time, hours, and fees pays off, Is the MI-MP Certification Worth It? Complete ROI Analysis 2026 lays out the considerations.
A Domain-Aware Approach to Preparing
Rather than reading the 2021 Plumbing Code Book start to finish, it helps to sequence your review around domain weight and difficulty. Drainage systems, venting, and the material takeoff are naturally linked - study them together, since the takeoff draws on both. Save Domain 11 (Skilled Trades Regulation Act, 2016 PA 407) for a focused session since it's statutory rather than code-based, and you'll be reading it onscreen during the actual exam rather than from your tabbed book.
Core Code Domains
- Drainage systems, water distribution, fixtures, backflow protection
- Build familiarity with code book structure and tab placement
Venting and Material Takeoff
- Practice back-to-back restroom takeoffs repeatedly
- Drill drain/vent sizing calculations under a timer
Testing, Inspections, Special Waste, Storm Drains
- Review procedural and administrative code sections
Statute Review and Full-Length Timing
- Study Skilled Trades Regulation Act, 2016 PA 407 provisions
- Run full 130-question, 180-minute timed simulations
For a structured, week-by-week study plan built specifically around these domains and the exam's open-book constraints, see MI-MP Study Guide 2026: How to Pass on Your First Attempt. And if you want to know precisely how the 75% threshold translates into how many questions you can afford to miss, check MI-MP Passing Score 2026: Exactly What You Need to Pass.
Renewal and Ongoing Requirements
Passing the MI-MP exam and getting licensed isn't the end of the obligation. Michigan Master Plumber licenses must be renewed every three years by April 30, with a $300 renewal fee. Additionally, licensees are required to complete code-update training within one year after a new plumbing code is adopted - so staying current with code revisions is a continuing professional obligation, not a one-time exam hurdle.
Before you even get to renewal, though, you need to schedule and pass the exam itself. Testing windows, blackout periods, and scheduling logistics through PSI are covered in MI-MP Exam Dates 2026: Testing Windows, Deadlines & Scheduling.
Key Takeaway
Treat the $300 triennial renewal and mandatory code-update training as part of the true long-term cost and commitment of holding a Master Plumber License - not just the $100 exam fee.
Frequently Asked Questions
MI-MP stands for the Michigan Master Plumber License Exam, administered by PSI Services LLC for LARA's Bureau of Construction Codes. See What Does MI-MP Stand For? for more detail.
The exam consists of 130 questions to be completed within 180 minutes, with a minimum passing score of 75%.
No. Under PSI test-center security rules, personal calculators must be stored outside the examination room.
Only a bound code book with chapter tabs. No additional papers, and no highlighting, underlining, or indexing added during the exam. The 2021 Plumbing Code Book is the listed reference in the current PSI bulletin.
The PSI examination fee is $100 per attempt, and this applies to every retake as well - there is no discounted retake fee.
Whether you're just starting to research the credential or you're deep into scheduling with PSI, understanding the MI-MP exam's specific structure - the 130 questions, the material takeoff, the eleven domains, and the strict open-book rules - is the foundation for walking in prepared. You can explore full practice materials and domain-specific drills on the main MI-MP Exam Prep site to build that readiness before test day.