- You need a raw score of 75% or higher on the PSI written exam to pass.
- The exam is 125 questions in 180 minutes - that's roughly 86 seconds per question on average.
- The written exam is open-book, but only unmarked, properly tabbed code books and staple-bound statutes are allowed.
- Passing the written exam and the separate BCC practical exam must both happen within the same one-year application period.
The Passing Score, Exactly
If you're searching for the single number that matters most before test day, here it is: the Michigan Journey Plumber written examination requires a minimum score of 75% to pass. That's the figure published in the PSI candidate bulletin governing the exam, and it applies to the 125-question, 180-minute computer-based test administered by PSI Services LLC on behalf of the Michigan Department of Licensing and Regulatory Affairs (LARA), Bureau of Construction Codes (BCC).
There's no partial credit for domain-level performance and no sliding scale based on experience or apprenticeship hours. Whether you've logged the state's required 6,000 hours over three years or you're testing at the edge of eligibility, the bar is identical: get at least 75 out of every 100 scoring points right, and you pass. Fall short, and you'll be scheduling a retake - at another $100 to PSI.
Why 75% Is Harder Than It Sounds
A 75% threshold looks straightforward on paper, but the difficulty comes from breadth, not from any single trick question. The written exam draws from three broad domains - Plumbing theory, The practice of plumbing, and Knowledge of the state plumbing code, rules and regulations - and each of those domains fans out into dense technical subtopics you're expected to apply, not just recognize.
Because the exam is open-book, candidates sometimes assume the passing score is easier to reach than a closed-book test. In practice, the opposite can be true: you're given 180 minutes to answer 125 questions and flip through your 2021 Michigan Plumbing Code, the State Construction Code Act (1972 PA 230), and the Skilled Trades Regulation Act (2016 PA 407) when needed. That's an average of under a minute and a half per question, and every second spent hunting for a code section is a second you don't get back. If you're unsure how the difficulty of this exam compares to other trade licensing tests, the breakdown in How Hard Is the MI-JP Exam? Complete Difficulty Guide 2026 goes deeper into why time pressure, not raw knowledge, trips up many first-time candidates.
Key Takeaway
Treat the open-book format as a safety net for edge cases, not a substitute for memorizing core code sections. If you have to look up every third question, you will run out of time before you reach question 125.
Exam Format and How Scoring Works
The PSI written exam for the Journey Plumber license is delivered on computer at a physical PSI test center - this is not a remote-proctored exam, so plan your travel and arrival time accordingly. Format basics:
- 125 scored questions, multiple-choice format
- 180 minutes total testing time
- Open-book with approved references only
- 75% minimum passing score to receive a passing result
- $100 fee charged by PSI per attempt, separate from LARA's $40 initial license fee
PSI reports a pass/fail result, and that result is tied to the specific application period you're testing under. A pass does not carry over if you let your application lapse and reapply later - you'd need to pass the written exam again under the new application. That single rule is easy to overlook and is one of the reasons candidates should map out their timeline before they ever schedule a seat. The scheduling mechanics, including the 30-day cutoff for the related practical session, are covered in more detail in MI-JP Exam Dates 2026: Testing Windows, Deadlines & Scheduling.
What the Three Domains Actually Test
The PSI bulletin organizes content into three broad domains, but the real preparation work happens in the technical subtopics underneath them: drainage systems, vent systems, fixtures, water distribution, backflow prevention, special waste systems, testing and inspections, and interpretation of isometric drawings. A full breakdown of how these subtopics map to each domain lives in MI-JP Exam Domains 2026: Complete Guide to All 3 Content Areas, but here's a working summary.
Domain 1: Plumbing Theory
This domain tests the underlying physical and hydraulic principles that make plumbing systems work - not just what the code says, but why the code says it. Expect questions rooted in flow, pressure, venting theory, and how design decisions prevent problems like siphonage or backflow.
- Hydraulic and pneumatic principles behind drainage and vent design
- Why backflow prevention devices are positioned where they are
- The theory connecting fixture unit loads to pipe sizing
Domain 2: The Practice of Plumbing
This domain is applied and scenario-based. It leans heavily on the practical, on-the-job subtopics: reading isometric drawings, sizing water distribution systems, installing special waste systems, and executing tests and inspections correctly.
- Interpreting isometric drawings under time pressure
- Testing and inspection sequencing for rough-in and final walkthroughs
- Fixture installation requirements and venting configurations
Domain 3: State Plumbing Code, Rules and Regulations
This domain is where your approved references matter most. Questions here draw directly from the 2021 Michigan Plumbing Code and the statutory framework established by the State Construction Code Act and Skilled Trades Regulation Act.
- Locating specific code sections quickly using your tabbed chapters
- Distinguishing statutory requirements (licensing, registration) from code requirements (installation)
- Knowing which rules govern backflow prevention, special waste, and drainage compliance
Open-Book Rules That Affect Your Score
PSI's open-book policy is generous compared to closed-book trade exams, but it comes with strict formatting rules that can cost you materials - and therefore points - if ignored on test day.
- Chapter tabs are allowed on your code books, but highlighting, underlining, handwritten notes, and any other markings are prohibited.
- Statutory references printed from the BCC website must be separate documents from your code book, each bound with three staples along the left edge, with no markings or tabs of their own.
- No additional loose or attached papers are permitted - no sticky notes, no printed cheat sheets, no extra pages inserted into your bound references.
If proctors flag your materials at check-in, you may lose access to a reference you were counting on - effectively turning part of the exam closed-book for you. Rehearsing with clean, properly tabbed copies of the 2021 Michigan Plumbing Code well before your test date is non-negotiable prep, and it's worth building into whatever study plan you follow, including the structured approach in MI-JP Study Guide 2026: How to Pass on Your First Attempt.
Fees, Retakes, and the One-Year Clock
Missing the 75% threshold isn't just a scheduling inconvenience - it's a financial one. PSI charges $100 per attempt, and that fee resets every time you sit for the exam again. LARA's application carries its own $40 initial license fee on top of that. A candidate who fails twice before passing has effectively paid for three attempts, which is a meaningful cost relative to the exam itself. A full cost breakdown, including how these fees compare to renewal costs, is available in MI-JP Certification Cost 2026: Complete Pricing Breakdown.
PSI does permit repeat written attempts, but every attempt has to fall within your active LARA application window - both the written exam and the BCC practical exam must be passed within the same one-year application period. A passing result on the written exam does not transfer to a new application if your window closes before you complete the practical portion. That makes the 75% passing score not just a knowledge bar, but a timing constraint: fail late in your window, and you may not have room left to retake and still pass the practical in time.
| Requirement | Detail |
|---|---|
| Passing score (written) | 75% minimum |
| Questions / Time | 125 questions / 180 minutes |
| Format | Computer-based, open-book, PSI test center |
| Retake fee | $100 per attempt (PSI) |
| Application window | Written and practical exams must both pass within one year |
Don't Forget the Practical Exam
Hitting 75% on the PSI written exam is only half the licensing equation. LARA and the Bureau of Construction Codes also require a separate hands-on practical examination, scheduled through BCC rather than PSI. The published practical session runs from 10:00 a.m. to 12:30 p.m., and scheduling requests must meet a 30-day cutoff - miss that window and you'll be pushed to the next available session, which eats into your one-year application clock.
Because both exams must be completed within the same application period, it makes sense to plan your written exam attempt with enough buffer to still schedule and pass the practical afterward. If you're early in the eligibility process - verifying your 6,000 hours of registered apprenticeship or gathering notarized employer experience statements - review the full checklist in MI-JP Requirements 2026: Eligibility, Prerequisites & How to Qualify before you lock in a test date.
A Four-Week Runway to 75%
There's no universal study formula for hitting a 75% passing score, but a structured runway helps you avoid cramming code sections the night before. Here's one sequence built around the exam's own domain weighting and reference rules.
Plumbing Theory Foundations
- Review hydraulic and pneumatic principles underlying drainage and venting
- Study backflow prevention theory before touching code specifics
Applied Practice Topics
- Drill isometric drawing interpretation under a timer
- Work through fixture, water distribution, and special waste scenarios
Code, Rules and Regulations
- Build and tab a clean, unmarked copy of the 2021 Michigan Plumbing Code
- Practice locating sections tied to testing and inspections quickly
Timed Simulation
- Take full-length practice tests at a 125-question, 180-minute pace
- Rehearse the exact reference materials, staple binding, and tabs you'll bring to PSI
Running full-length, timed simulations against a 125-question format on our MI-JP practice test platform is the closest you'll get to feeling the real 86-second-per-question pace before test day. Pair that with domain-specific drilling from MI-JP Cheat Sheet 2026: One-Page Review of Must-Know Facts so your code-lookup speed matches the clock, not just your knowledge.
Key Takeaway
Save your code-book navigation drills for Week 3 and 4 - practicing lookups too early wastes time on sections you haven't yet studied conceptually.
Frequently Asked Questions
You need a minimum score of 75% on the 125-question PSI written exam to receive a passing result.
The 75% figure specifically applies to the PSI written examination. The BCC hands-on practical exam is scored separately, and both must be passed within the same one-year application period.
Yes. PSI permits repeat attempts, each requiring a new $100 exam fee, as long as the retake falls within your active LARA application window.
Yes, but only approved, unmarked references are allowed: a tabbed 2021 Michigan Plumbing Code and separately staple-bound statutory printouts, with no highlighting, notes, or loose papers permitted.
No. A passing written exam result does not transfer to a new LARA application. Both the written and practical exams must be completed within the same one-year period.