- You need a 73% passing score on the 100-question TN-CMCA exam.
- That means roughly 73 correct answers out of 100 - no domain-by-domain minimums exist.
- Drain, Waste, and Vent Systems (20%) and Isometrics (18%) carry the heaviest weight.
- The exam is open-book with a 5-hour limit and costs $53 per attempt through Prov.
The Exact Passing Score You Need
If you're preparing for the Tennessee Plumbing (CMC-A) Contractor Examination, the single most important number to memorize is 73%. That is the passing score set by the Tennessee Board for Licensing Contractors for this exam, administered through Prov under the current bulletin dated July 13, 2026. On a 100-question exam, 73% translates directly into roughly 73 correct answers out of 100 - there's no scaled scoring formula or curve to worry about, and no separate cut score per domain.
That simplicity is a double-edged sword. On one hand, you know exactly what target you're chasing. On the other, because there's no minimum-per-domain requirement, a weak spot in a heavily weighted domain like Drain, Waste, and Vent Systems can sink your overall score even if you're strong everywhere else. Understanding how the 73% threshold interacts with the exam's domain structure is the real key to passing on your first attempt.
Exam Format: 100 Questions, 5 Hours, Open Book
The TN-CMCA exam is a computer-based, multiple-choice test delivered either at a Prov test center or remotely through Examroom. Candidates get 100 questions and up to five hours to complete them - a generous window that rewards careful reading and reference use over speed. Because the exam is open-book, you're allowed to bring and consult the approved references during the test:
- 2021 International Plumbing Code
- 2018 or 2021 International Fuel Gas Code
- Mathematics for Plumbers and Pipefitters, 8th Edition
- OSHA 29 CFR Part 1926
- Plumbing Basics for Contractors, 4th Edition (2021)
Open-book doesn't mean easy - it means the exam expects you to know how to locate and apply code sections and formulas quickly rather than memorize them verbatim. If you've never timed yourself flipping through the IPC or working a pipe-sizing formula from the math reference under pressure, you're not actually ready, regardless of how well you understand the concepts. For a deeper breakdown of why this open-book format still trips up experienced plumbers, see How Hard Is the TN-CMCA Exam? Complete Difficulty Guide 2026.
Why Domain Weighting Changes Your Math
The exam draws questions from twelve content domains, and they are not weighted equally. Two domains dominate the blueprint:
Domain 11: Drain, Waste, and Vent Systems (20%)
The single largest domain on the exam. Candidates must understand trap arrangements, vent sizing, cleanout placement, and drainage fixture unit calculations as they apply under the 2021 IPC.
- Expect the most questions from this domain of any single area
Domain 9: Isometrics (18%)
The second-largest domain, testing your ability to read and interpret isometric plumbing drawings - a skill that's hard to fake and easy to lose points on if you haven't practiced with actual isometric diagrams.
- Combined with DWV, these two domains account for nearly two out of every five questions
The remaining ten domains - General Knowledge, Plumbing Math, Code Requirements, Fixtures and Fittings, Water Heaters, Storm Drainage, Fuel Gas Systems, OSHA Safety, Water Supply and Distribution, and Tools and Installation Practices - fill out the rest of the exam. None of these carry the same individual weight as DWV or Isometrics, but collectively they represent the majority of the test, so you can't afford to write off any single one. For the full breakdown of what each domain actually covers, see TN-CMCA Exam Domains 2026: Complete Guide to All 12 Content Areas.
Key Takeaway
Because DWV and Isometrics together make up 38% of the exam, prioritizing mastery in these two domains gives you the best return on study time toward hitting 73% overall.
Doing the Scoring Math by Domain
There's no published minimum score per domain, which means the 73% requirement is purely a total-exam threshold. But because the domains are weighted, it helps to think in approximate question counts rather than abstract percentages. On a 100-question exam, a 20% domain like Drain, Waste, and Vent Systems roughly translates to about 20 questions, and an 18% domain like Isometrics to about 18 questions. Missing several questions in either of these two domains has a much larger impact on your raw score than missing the same number in a smaller domain.
| Domain | Approx. Weight | Relative Impact |
|---|---|---|
| Drain, Waste, and Vent Systems | 20% | Highest - largest single domain |
| Isometrics | 18% | Second highest |
| Remaining 10 domains combined | ~62% | Individually smaller, collectively decisive |
This is why candidates who treat every domain as "equally important in theory, but not in study time" tend to do better. Spend disproportionate review time on the two heavyweight domains, but don't neglect the other ten - together they still represent the majority of the exam. A structured walk-through of exactly what belongs in each domain is available in TN-CMCA Study Guide 2026: How to Pass on Your First Attempt.
Registration, Fees, and Preapproval Before You Sit
Before you can even schedule the exam and start thinking about hitting 73%, you have to clear the Board's preapproval process. This isn't optional paperwork - it's a gate that determines whether you're eligible to test at all.
- Preapproval fee: $50, paid separately from the exam fee
- Experience requirement: at least three years of plumbing experience, or a degree in plumbing or mechanical engineering, with documentation
- Exam fee: $53 per attempt, paid to Prov
- Companion exam: you must also pass Tennessee Business and Law
- Additional requirements: financial capacity, references, liability insurance, and workers' compensation documentation
Once you pass, your exam scores are typically valid for two years, which matters if you're staggering the plumbing exam and Business and Law around other licensing steps. The full eligibility checklist - including what counts as acceptable documentation - is covered in TN-CMCA Requirements 2026: Eligibility, Prerequisites & How to Qualify. If you're still mapping out total costs, including the $250 initial contractor application fee and $200 biennial renewal, see TN-CMCA Certification Cost 2026: Complete Pricing Breakdown.
Building a Score-Focused Study Plan
With a fixed 73% target and known domain weights, your prep plan should be built backward from the blueprint rather than around generic study habits. A simple way to allocate a multi-week prep window:
Drain, Waste, and Vent Systems + Isometrics
- Work through IPC drainage and venting sections until you can locate any table in under a minute
- Practice reading isometric drawings repeatedly, since this domain is visual and skill-based, not just recall-based
Code Requirements, Water Supply and Distribution, Fixtures and Fittings
- Cross-reference the 2021 IPC with real installation scenarios
- Drill fixture unit and pipe sizing calculations using the plumbing math reference
Fuel Gas Systems, Water Heaters, Storm Drainage, OSHA Safety
- Review the Fuel Gas Code and OSHA 29 CFR Part 1926 sections most likely to appear
- Practice timed open-book lookups so you're fast under exam-day pressure
General Knowledge, Plumbing Math, Tools and Installation Practices
- Take full-length timed practice exams to simulate the 5-hour window
- Review weak domains identified from practice results
This is intentionally not a generic Pomodoro-and-flashcards schedule - it's sequenced specifically around the fact that DWV and Isometrics carry the most weight, so they get addressed first and revisited last. For domain-specific breakdowns of what to actually study inside each week, cross-reference the full guide at TN-CMCA Exam Domains 2026: Complete Guide to All 12 Content Areas, and run realistic timed sets on our TN-CMCA practice test platform to see how your score tracks against the 73% threshold before exam day.
Key Takeaway
Practice under the same open-book, 5-hour, 100-question conditions you'll face at Prov - timing yourself with the actual reference books, not just your notes.
What Happens After You Pass (or Don't)
Passing the 73% threshold clears one major hurdle, but licensure isn't automatic. You still need to satisfy the Board's remaining requirements - financial capacity, references, liability insurance, workers' compensation - and pay the $250 initial contractor application fee. Once licensed, renewal comes around every two years at $200.
If you don't clear 73% on your first attempt, remember the $53 fee applies per attempt, and your underlying preapproval typically remains valid for retesting within the two-year score validity window - though you'll want to confirm current retake policies directly with Prov and the Board. Rather than guessing where you lost points, review performance data and adjust your study allocation toward the domains that pulled your score down, especially if DWV or Isometrics were weak spots.
Curious how your target score compares to what other candidates typically experience, or whether the credential pays off once you're licensed? See TN-CMCA Pass Rate 2026: What the Data Shows and Is the TN-CMCA Certification Worth It? Complete ROI Analysis 2026 for more context, or explore TN-CMCA Jobs to see who's hiring licensed CMC-A contractors across Tennessee.
FAQ
You need a 73% passing score, which on the 100-question exam works out to roughly 73 correct answers.
No. The 73% requirement applies to your overall score across all 100 questions, not to each of the 12 individual domains separately.
Since the passing score is 73%, you can miss up to approximately 27 questions out of 100 and still pass, though this is an approximation based on the stated percentage.
It helps, but only if you practice using the approved references - the 2021 IPC, Fuel Gas Code, plumbing math text, OSHA 29 CFR Part 1926, and Plumbing Basics for Contractors - quickly under time pressure before test day.
Exam scores are typically valid for two years, which gives you time to complete other licensing steps like the Tennessee Business and Law exam and application requirements.