- 130 questions, 180 minutes, 75% minimum passing score - no partial credit tricks to rely on.
- The PSI bulletin effective April 29, 2026 uses the 2021 Plumbing Code Book as the exam reference.
- Eligibility requires 4,000 journey-plumber hours over the two years before applying, with no licensure lapse.
- Only a bound code book with chapter tabs is allowed - no loose papers, highlighting, or indexing.
Exam Basics at a Glance
Before you dive into study materials, get the mechanics locked into memory. The Michigan Master Plumber License Exam is administered by PSI Services LLC on behalf of the Michigan Department of Licensing and Regulatory Affairs (LARA), Bureau of Construction Codes. It is a 130-question, 180-minute computer-administered exam, and you need a 75% minimum passing score to earn the Master Plumber License.
This cheat sheet is meant to be a single-page reference you can scan the night before test day. For the full breakdown of how the exam is structured and weighted, see the MI-MP Exam Domains 2026: Complete Guide to All 11 Content Areas, and if you're still building your overall prep timeline, start with the MI-MP Study Guide 2026: How to Pass on Your First Attempt.
Eligibility Snapshot
You can't sit for this exam without meeting LARA's eligibility criteria first. Applicants must be at least 18 years old and have accumulated 4,000 hours working as a journey plumber during the two years immediately preceding application. Critically, there can be no lapse in journey licensure during that two-year window - if your journey license expired at any point, that gap can derail your application even if your total hours add up.
LARA approval of your application is required before PSI will let you schedule the exam. For a deeper walkthrough of documentation, hour verification, and common application pitfalls, check MI-MP Requirements 2026: Eligibility, Prerequisites & How to Qualify.
Eligibility Checklist
Confirm each item before submitting your application to LARA.
- At least 18 years old at time of application
- 4,000 hours as a journey plumber within the prior two years
- No lapse in journey licensure during that two-year period
- LARA application approved before scheduling with PSI
The 11 Domains, Fast
PSI's subject list breaks the exam into eleven domains. You won't get an official domain-by-domain weighting published for public study, so treat every domain as fair game rather than trying to guess which one carries the most questions. Here's the list, condensed:
Domain 1: Drainage Systems
Pipe sizing, slope, fixture unit loads, and layout logic for waste removal.
- Know how fixture units translate into pipe diameter requirements
Domain 2: General Knowledge
Broad code literacy and terminology that underpins every other domain.
- Expect definitional and code-reference style questions
Domain 3: Fixtures
Fixture requirements, minimum clearances, and connection standards.
- Memorize fixture unit values for common fixtures
Domain 4: Water Distribution
Supply pipe sizing, pressure, and material selection.
- Practice sizing problems using demand and pressure loss
Domain 5: Backflow Protection
Cross-connection control and device selection by hazard level.
- Match backflow prevention devices to specific hazard scenarios
Domain 6: Storm Drains
Roof drainage, sizing by rainfall rate, and discharge requirements.
- Review conductor and leader sizing tables
Domain 7: Special Waste
Handling of waste requiring separate treatment before discharge.
- Know when interceptors or separators are required
Domain 8: Testing
Required test procedures for new and altered systems.
- Understand air, water, and smoke test requirements
Domain 9: Inspections
Inspection sequencing and what must be visible or accessible.
- Know the order of rough-in versus final inspections
Domain 10: Venting
Vent sizing, distance limits, and acceptable venting methods.
- This overlaps heavily with the material takeoff drawing question
Domain 11: Knowledge of the Skilled Trades Regulation Act, 2016 PA 407
Licensing law, not plumbing code - a distinct legal knowledge area.
- The Act is supplied onscreen during the exam, but you must know how to apply it
For a domain-by-domain study plan with resource recommendations, the MI-MP Exam Domains 2026 guide goes much deeper than this summary allows.
Material Takeoff Question Format
This is the part of the exam that catches candidates off guard if they haven't practiced it. The computer-administered exam includes a drawing-based material takeoff section built around back-to-back restrooms. You'll be asked to work from a plan drawing to determine fitting quantities, drain and vent sizing, and appropriate venting methods based on what's shown.
This isn't a multiple-choice recall question - it's applied reasoning that draws directly on Domain 1 (drainage systems) and Domain 10 (venting) knowledge simultaneously. If you've only memorized code tables without practicing how to read a takeoff drawing, this section can cost you points you didn't expect to lose.
Key Takeaway
Practice reading back-to-back restroom layouts specifically. Being able to recite vent sizing rules from memory isn't the same skill as extracting fitting counts and vent placement from an actual drawing under time pressure.
Because this format is unusual compared to straight code-lookup questions, many candidates underestimate how much prep time it deserves. If you're trying to gauge how tough the overall exam really is relative to other trade licensing tests, How Hard Is the MI-MP Exam? Complete Difficulty Guide 2026 covers this in more detail, and MI-MP Pass Rate 2026: What the Data Shows discusses what the available data indicates about candidate outcomes.
What You Can (and Can't) Bring In
The exam is open book, but the rules are strict and specific. Here's what's actually allowed:
| Allowed | Not Allowed |
|---|---|
| Bound 2021 Plumbing Code Book | Loose papers or personal notes |
| Chapter tabs in the code book | Highlighting or underlining in the reference |
| State Construction Code Act, 1972 PA 230 (supplied onscreen) | Personal paper copies of the Act |
| Skilled Trades Regulation Act, 2016 PA 407 (supplied onscreen) | Indexing or writing inside the code book |
| Test-center provided calculator functions | Personal calculators inside the exam room |
Note that both the State Construction Code Act and the Skilled Trades Regulation Act are supplied onscreen during the exam - you don't bring your own copies, and personal paper versions are prohibited. Personal calculators must be stored outside the testing room entirely under PSI's test-center security rules, so don't plan on using your own device even if you leave it in a bag.
Fees, Retakes, and Renewal Cycle
Money and deadlines matter as much as code knowledge. The PSI examination fee is $100 per attempt, and that fee applies to retakes too - there's no discounted retake rate, so a failed attempt is a full $100 again. Budget accordingly if you're not confident heading into test day, and treat every attempt as one you intend to pass.
Once licensed, the Master Plumber License must be renewed every three years by April 30, with a $300 renewal fee. Keep in mind the license is distinct from a plumbing contractor license - they are separate credentials with separate scopes, so don't assume one covers the other. Also note that code-update training is required within one year after a new plumbing code is adopted, so renewal isn't purely a fee-and-forget process.
For a full cost picture including exam fees, renewal fees, and other expenses tied to getting and keeping this license, see MI-MP Certification Cost 2026: Complete Pricing Breakdown. If you're weighing whether the investment of hours and money is worth it relative to career outcomes, Is the MI-MP Certification Worth It? Complete ROI Analysis 2026 and MI-MP Salary Guide 2026: Complete Earnings Analysis are useful companion reads.
Key Takeaway
Every attempt costs $100 regardless of whether it's your first try or your third. Treat your practice test scores as your real signal of readiness before you pay to sit for the actual exam.
Final-Week Review Plan
In the last week before your scheduled exam date, don't try to learn new material - focus on retrieval and drawing practice instead. A tight final-week structure looks like this:
Drainage, Venting & the Takeoff Drawing
- Redo back-to-back restroom takeoff practice problems from scratch
- Cross-check drain and vent sizing answers against the 2021 code book
Water Distribution, Backflow & Storm Drains
- Run sizing calculations for supply lines and roof drainage
- Review backflow device selection by hazard classification
Fixtures, Special Waste, Testing & Inspections
- Drill fixture unit values and interceptor requirements
- Review required test procedures and inspection sequencing
Legal Knowledge & Logistics
- Review Skilled Trades Regulation Act, 2016 PA 407 concepts
- Confirm test-center or remote-proctor login details, ID, and code book tabs
This structure deliberately front-loads the material takeoff-adjacent domains (drainage and venting) since that question format rewards practiced pattern recognition more than last-minute cramming. For a broader prep framework beyond just the final week, revisit the MI-MP Study Guide 2026, and confirm your target sitting date against current scheduling windows in MI-MP Exam Dates 2026: Testing Windows, Deadlines & Scheduling.
Once you're licensed, plenty of employers specifically seek out master-level credential holders for supervisory and permit-pulling roles. If you're mapping out what comes after the exam, MI-MP Jobs and MI-MP Training cover next steps, and you can sharpen your readiness right now with a Michigan master plumber practice test built around these same eleven domains.
FAQ
The exam has 130 questions with a time limit of 180 minutes, and you need a minimum score of 75% to pass.
Per the PSI bulletin effective April 29, 2026, the exam reference is the 2021 Plumbing Code Book. You may bring a bound copy with chapter tabs, but no loose papers, highlighting, or indexing.
No. Personal calculators must be stored outside the examination room under PSI test-center security rules.
The PSI examination fee is $100 per attempt, and that same fee applies to retakes - there is no reduced retake price.
Renewal is required every three years by April 30, with a $300 renewal fee. Code-update training is also required within one year after a new plumbing code is adopted.
Keep this cheat sheet handy as a quick-reference companion, but pair it with full domain review and drawing practice well before test day - the material takeoff section in particular rewards repetition over memorization alone.