- The CO-MP exam is 120 scored questions in 270 minutes, plus up to 10 unscored items in an added 30 minutes.
- Passing requires 70% (84 of 120 scored questions) per the June 18, 2026 PSI bulletin.
- Sanitary Drainage Systems (22 questions) and Vents (20 questions) carry the heaviest domain weight.
- Only PSI-supplied 2021 IPC and IRC are allowed at the terminal - no personal books, tabs, or formula sheets.
CO-MP Exam Overview
The Colorado Master Plumber License Exam (CO-MP) is administered through PSI Services LLC on behalf of the Colorado State Plumbing Board within DORA. It's a computer-based, multiple-choice exam built to confirm that a candidate can safely and correctly apply plumbing code across eleven distinct content areas. If you're still getting oriented to the credential itself, start with What Is CO-MP? and CO-MP Requirements 2026: Eligibility, Prerequisites & How to Qualify before diving into this cheat sheet.
This page is a condensed, one-stop reference. For deeper prep, pair it with the CO-MP Study Guide 2026: How to Pass on Your First Attempt, and use our practice test platform to drill the exact question format under timed conditions before test day.
Registration, Fees, and Scheduling
Every CO-MP candidate deals with the same fee structure and scheduling mechanics:
- Initial exam fee: $78
- Retake fee: $73
- Payment validity: one year from the date paid
- Delivery method: computer-based testing through PSI
Because payment is only good for one year, candidates who delay scheduling risk having to repay before they ever sit for the exam. For a full cost breakdown covering fees, materials, and related expenses, see CO-MP Certification Cost 2026: Complete Pricing Breakdown. If you need help mapping out testing windows and deadlines, the CO-MP Exam Dates 2026: Testing Windows, Deadlines & Scheduling guide covers scheduling logistics in detail.
Key Takeaway
Always confirm the current PSI bulletin before scheduling - code edition and passing standard are subject to update, and the bulletin introduction still references 2018 codes even though the reference section specifies 2021 IPC and IRC.
Domain-by-Domain Breakdown
The CO-MP exam covers eleven domains with fixed scored-item counts. Knowing exactly how many questions come from each area lets you allocate study time proportionally instead of studying everything equally.
| Domain | Scored Questions |
|---|---|
| 1. Water Supply | 16 |
| 2. Vents | 20 |
| 3. Fixtures and Equipment | 10 |
| 4. General Regulations | 6 |
| 5. Traps, Interceptors, and Separators | 6 |
| 6. Storm Drainage Systems | 12 |
| 7. Sanitary Drainage Systems | 22 |
| 8. Indirect and Special Waste Piping | 6 |
| 9. Isometric Analysis | 10 |
| 10. Residential Fire Sprinklers | 4 |
| 11. Water Heaters | 8 |
That's 120 scored questions total. Sanitary Drainage Systems and Vents together account for 42 of them - more than a third of the exam. If you only had time to master two domains, these would be the two.
Sanitary Drainage Systems (22 questions)
The single largest domain. Expect deep coverage of pipe sizing, slope, cleanout placement, building drain and sewer requirements, and fixture unit calculations.
- Drainage fixture unit tables and how they drive pipe sizing
- Cleanout spacing and access requirements
- Building drain vs. building sewer distinctions
Vents (20 questions)
The second-heaviest domain, covering venting methods, sizing, and the relationships between vent systems and trap protection.
- Individual, common, wet, and circuit venting rules
- Vent sizing based on developed length and fixture units
- Air admittance valve permissible uses
For a full walkthrough of every content area, including subtopics not summarized here, read the CO-MP Exam Domains 2026: Complete Guide to All 11 Content Areas. It's the natural companion to this cheat sheet when you need more than a one-page summary.
Reference Materials: 2021 IPC/IRC Rules
PSI supplies the reference codebooks at the testing center - you do not bring your own. The dedicated reference section of the bulletin specifies the 2021 IPC and IRC. A few rules apply strictly:
- You cannot write in, highlight, underline, or index the supplied books.
- Personal reference books and formula sheets are prohibited entirely.
- Colorado-specific amendments are not tested on the CO-MP exam.
- An on-screen calculator is provided during the exam.
Passing Score and Scoring Method
Per the June 18, 2026 PSI bulletin, the passing standard is 70% overall, which equates to 84 correct answers out of 120 scored questions. This is based on overall performance across the exam rather than domain-by-domain minimums, so a weak showing in one domain can be offset by strength elsewhere - though given how heavily Sanitary Drainage Systems and Vents are weighted, neglecting either one is risky.
The up-to-10 unscored questions are mixed in but do not count toward your result; you won't know which ones they are, so treat every question on screen as if it counts. For the full mechanics of how the score is calculated and what it means for your prep priorities, see CO-MP Passing Score 2026: Exactly What You Need to Pass. If you're wondering how CO-MP compares in difficulty to other licensing exams, How Hard Is the CO-MP Exam? Complete Difficulty Guide 2026 and CO-MP Pass Rate 2026: What the Data Shows go into more depth on that question.
Key Takeaway
84 out of 120 is your number. Track practice-test scores against that exact threshold, not a vague "get most of it right" goal.
Experience Hours and Licensure Path
Passing the CO-MP exam is only one piece of becoming a licensed Master Plumber in Colorado. The Colorado State Plumbing Board requires 8,500 verified practical-experience hours, and a critical rule governs how those hours get documented:
- Applicants cannot verify their own experience - someone else must attest to your hours.
- You take the examination before applying for the license.
- Passing the exam does not by itself establish experience eligibility - the hours requirement is separate and must be documented independently.
This sequencing trips up candidates who assume passing the exam is the finish line. It isn't. Review the full eligibility chain, including how experience hours are typically documented, in CO-MP Requirements 2026: Eligibility, Prerequisites & How to Qualify.
Continuing Education and Renewal
Once licensed, renewal isn't a one-time formality. Colorado requires 8 continuing education hours each year, totaling 16 hours across the March 1, 2025 - February 28, 2027 cycle. There's an important exception:
- First-time licensees who obtained licensure by examination are exempt from CE requirements until their first renewal.
- Starting March 1, 2027, renewal terms shift to a three-year cycle.
Mark these dates now, especially if you're licensing close to the cycle boundary - the CE math changes depending on when you enter the system.
Language and Accommodation Options
PSI offers the CO-MP exam in both English and Spanish. For candidates who qualify for ESL accommodations, two specific options are approved:
- Time-and-a-half extended testing time
- A qualifying translation dictionary at the testing center
These accommodations must be requested and approved in advance of scheduling - they are not something you can request at the test center on exam day.
A One-Week Final Review Plan
If you're in the final stretch before your scheduled date, allocate review time proportionally to scored-question weight rather than evenly across all eleven domains. This isn't a generic study calendar - it's built around the CO-MP's specific point distribution.
Heaviest Domains First
- Sanitary Drainage Systems (22 questions) - pipe sizing, cleanouts, fixture units
- Vents (20 questions) - venting methods and sizing rules
Mid-Weight Domains
- Storm Drainage Systems (12 questions)
- Water Supply (16 questions)
- Fixtures and Equipment (10 questions) and Isometric Analysis (10 questions)
Lighter Domains and Full Practice Runs
- Water Heaters (8 questions), General Regulations (6), Traps/Interceptors/Separators (6), Indirect and Special Waste Piping (6), Residential Fire Sprinklers (4)
- Run a full 120-question timed simulation on the practice test platform
Reset and Rules Check
- Review only missed practice questions - don't re-study everything
- Reconfirm testing center reference book rules and reread the current PSI bulletin
This proportional approach mirrors how the exam is actually built: Sanitary Drainage Systems and Vents alone are worth as much as the bottom six domains combined. Spending review time evenly across all eleven areas wastes hours on low-weight content like Residential Fire Sprinklers at the expense of the domains most likely to determine your pass/fail outcome.
FAQ
There are 120 scored multiple-choice questions with 270 minutes to complete them. Up to 10 unscored questions may also appear, adding 30 more minutes to your total seat time.
Per the June 18, 2026 PSI bulletin, passing requires 70%, which is 84 correct answers out of the 120 scored questions, based on overall performance.
No. PSI supplies the 2021 IPC and IRC at the testing center, and you cannot write in, highlight, underline, or index them. Personal reference books and formula sheets are strictly prohibited.
No - candidates take the examination before applying for the license. However, passing the exam does not by itself establish your 8,500 hours of experience eligibility, and you cannot verify your own hours.
Yes, testing is available in English and Spanish. Approved ESL accommodations include time-and-a-half extended time and a qualifying translation dictionary, both of which must be arranged in advance.