- NV-C1 stands for Nevada's Plumbing and Heating Contractor (C-1) trade exam, issued by the Nevada State Contractors Board.
- The exam has 120 scored questions over five hours; 84 correct answers (70%) is passing.
- PSI charges $95 for the trade exam alone or $140 when paired with the CMS business-and-law exam.
- Drain, Waste, and Vents carries the heaviest weight at 10 items out of 120.
What Does NV-C1 Stand For?
NV-C1 refers specifically to the Nevada Plumbing and Heating Contractor (C-1) Trade Exam, the licensing examination administered on behalf of the Nevada State Contractors Board (NSCB) through PSI Services LLC. This is the full C-1 exam covering plumbing, heating, and mechanical systems together - it is a broader test than the narrower C-1d plumbing-only examination, and confusing the two can send a candidate studying the wrong scope entirely.
If you're just getting oriented, our companion pieces What Is NV-C1? and NV-C1 Meaning walk through the terminology in more depth. This article focuses narrowly on unpacking the letters and numbers themselves and what they mean for anyone preparing to sit the exam in Nevada.
Who Administers the NV-C1 Exam
The Nevada State Contractors Board sets licensing policy, approves applications, and determines who is eligible to sit the exam. PSI Services LLC is the testing vendor that builds and delivers the actual exam content, per its bulletin (last updated March 25, 2026). Board approval must happen before PSI will schedule a testing appointment - candidates cannot simply register with PSI on their own initiative.
Typical qualifying experience is four full years of journeyman, supervisory, or contractor-level work within the preceding 15 years, though Board-approved education can substitute for up to three of those years. Applicants also need to satisfy financial, bond, and applicable insurance requirements before a license is issued. For a full breakdown of eligibility mechanics, see NV-C1 Requirements 2026: Eligibility, Prerequisites & How to Qualify.
Fee Structure
PSI charges $95 to sit the trade exam alone, or $140 if you're testing on both the trade exam and the CMS business-and-law exam in the same sitting. Separately, the Board charges a $300 application fee, and licensing itself runs $600 for the initial two-year license and another $600 at each biennial renewal. A detailed cost breakdown, including how these fees stack up across the full licensing timeline, is available in NV-C1 Certification Cost 2026: Complete Pricing Breakdown.
Key Takeaway
Budget for four separate payments across the process: the $95-$140 PSI exam fee, the $300 Board application fee, and $600 for licensing - repeated every two years at renewal.
Exam Format, Timing, and Passing Score
The C-1 trade exam is computer-administered and open-book, with 120 scored questions and a five-hour time limit. PSI may insert between one and ten additional unscored experimental questions, and these count against your total exam time even though they aren't graded - so the clock effectively runs faster than the scored question count alone would suggest.
A passing score is 84 correct answers out of 120, which works out to exactly 70%. That threshold is fixed and doesn't scale with question difficulty. For the exact math behind that number and how it compares to other Nevada trade exams, read NV-C1 Passing Score 2026: Exactly What You Need to Pass.
If a candidate fails, Nevada requires a two-week waiting period before retesting, and three failed attempts voids the application outright - meaning you'd need to reapply from scratch. That makes first-attempt preparation far more valuable than treating the exam as a low-stakes trial run. Our How Hard Is the NV-C1 Exam? Complete Difficulty Guide 2026 article digs into why the open-book format doesn't make this an easy test.
The 23 Domains and How They're Weighted
The NV-C1 blueprint spans 23 domains, from Boilers and Gas Systems through niche areas like Breathing Systems for Firefighters and Chilled Water Piping. Each domain has a fixed item count that determines how much study time it deserves. A full breakdown of every domain's content and study angle is available in NV-C1 Exam Domains 2026: Complete Guide to All 23 Content Areas, but here's the official allocation:
| Domain | Scored Items |
|---|---|
| 1. Boilers | 4 |
| 2. Gas Systems | 8 |
| 3. Cleanouts | 4 |
| 4. Fixtures and Equipment | 4 |
| 5. Hydronics | 3 |
| 6. Water Heaters/Venting | 6 |
| 7. Piping, Valves, and Controls | 3 |
| 8. Sheet Metal | 3 |
| 9. Water Supply | 8 |
| 10. Hangers and Supports | 5 |
| 11. Drain, Waste, and Vents | 10 |
| 12. Backflow | 4 |
| 13. Traps and Interceptors | 8 |
| 14. Isometric Analysis/Plumbing Mathematics | 8 |
| 15. Safety | 5 |
| 16. Joints and Connections | 4 |
| 17. Solar | 4 |
| 18. General Plumbing Requirements | 7 |
| 19. Fire Sprinklers | 5 |
| 20. Storm Drainage | 5 |
| 21. Industrial Piping | 3 |
| 22. Breathing Systems for Firefighters | 3 |
| 23. Chilled Water Piping | 6 |
Five domains carry the highest weight and deserve proportionally more of your study hours: Drain, Waste, and Vents (10 items), followed by Gas Systems, Water Supply, Traps and Interceptors, and Isometric Analysis/Plumbing Mathematics, each carrying 8 items. Together those five domains account for 42 of the 120 scored questions - more than a third of the entire exam.
Drain, Waste, and Vents
As the single largest domain, DWV questions test venting configurations, trap arm distances, cleanout placement logic, and pipe sizing under UPC 2018 rules. Candidates should be fluent in reading DWV isometrics before test day.
- Practice sizing vent pipes against fixture unit tables
- Know slope requirements for horizontal drain runs
- Cross-reference cleanout spacing rules directly in UPC 2018
Isometric Analysis/Plumbing Mathematics
This domain blends code knowledge with applied math - pipe sizing calculations, fixture unit totals, and reading isometric drawings under time pressure. It's one of four domains tied at 8 items, so treat it with the same seriousness as Gas Systems or Water Supply.
- Practice converting fixture units to pipe diameter
- Work through sample isometrics without a reference sheet first
- Bring a compliant silent, nonprogrammable calculator without an alphabetic keyboard
Approved References for the Open-Book Exam
Because NV-C1 is open-book, knowing exactly what you're allowed to bring is as important as knowing the code itself. PSI permits exactly five reference texts inside the testing room:
- UPC 2018 (Uniform Plumbing Code)
- UMC 2018 (Uniform Mechanical Code)
- NFPA 54 (2012) - National Fuel Gas Code
- NFPA 58 (2014) - Liquefied Petroleum Gas Code
- NFPA 13 (2019) - Installation of Sprinkler Systems
PSI's bulletin also lists additional study references used for exam development that candidates cannot bring into the room - don't confuse a study reference with an admitted reference. Advance highlighting, underlining, and permanent tabs in your five approved books are allowed, but handwritten notes, loose papers, and temporary tabs are not. A silent, nonprinting, nonprogrammable calculator without an alphabetic keyboard is permitted for the math-heavy questions in domains like Isometric Analysis/Plumbing Mathematics and Hydronics.
For a condensed list of exactly which editions to buy and how to tab them before test day, see Nevada C-1 exam books guidance woven throughout our NV-C1 Study Guide 2026: How to Pass on Your First Attempt.
Who Actually Needs This License
The C-1 classification is pursued by tradespeople who want to legally bid, contract, and supervise plumbing and heating installations in Nevada as a business owner or qualifying individual - not entry-level apprentices. Employers hiring for these roles include mechanical contracting firms, plumbing and HVAC companies, and design-build outfits that need a licensed qualifier on record with the Nevada State Contractors Board. If you're weighing whether this path fits your career goals, Is the NV-C1 Certification Worth It? Complete ROI Analysis 2026 and NV-C1 Salary Guide 2026: Complete Earnings Analysis cover the practical upside, while NV-C1 Jobs looks at what roles typically require or reward this license.
Because the C-1 covers both plumbing and heating systems - rather than the narrower C-1d plumbing-only path - it's the right target for contractors who want to bid mechanical work spanning boilers, hydronics, gas piping, and fire sprinkler tie-ins, not just drain and supply lines.
Mapping a Study Plan to the Blueprint
Rather than studying all 23 domains equally, allocate time proportionally to item count. A simple week-by-week structure built around the blueprint's heaviest domains looks like this:
Highest-Weight Domains
- Drain, Waste, and Vents (10 items) - sizing, venting, cleanouts
- Gas Systems (8 items) - NFPA 54 and NFPA 58 cross-references
Remaining 8-Item Domains
- Water Supply - pipe sizing and pressure loss
- Traps and Interceptors - separation and sizing rules
- Isometric Analysis/Plumbing Mathematics - calculator-based practice
Mid-Weight Domains (5-7 items)
- General Plumbing Requirements, Hangers and Supports, Safety, Fire Sprinklers, Storm Drainage
Lower-Weight and Niche Domains
- Boilers, Cleanouts, Fixtures, Backflow, Solar, Joints, Sheet Metal, Hydronics, Piping/Valves/Controls, Industrial Piping, Breathing Systems for Firefighters, Chilled Water Piping
- Full timed practice exam under five-hour conditions
This structure front-loads the domains with the most scoring impact while still leaving dedicated time for the smaller-weight domains that, combined, still make up over half the exam. For a deeper walkthrough of pacing strategy and time management inside the five-hour window, our NV-C1 Study Guide 2026: How to Pass on Your First Attempt covers this in more detail, and the NV-C1 Cheat Sheet 2026: One-Page Review of Must-Know Facts is useful for a final review pass the week before your appointment.
Key Takeaway
Don't spread study time evenly across 23 domains - the five highest-weighted domains alone account for over a third of the scored questions.
Before locking in a testing date, it's worth reviewing NV-C1 Exam Dates 2026: Testing Windows, Deadlines & Scheduling so your study timeline lines up with Board approval and PSI scheduling availability - Board sign-off has to happen first, and that process takes time. You can also start building familiarity with the question style using timed practice sets on the main NV-C1 practice test platform before committing to a fixed exam date.
Frequently Asked Questions
NV-C1 is Nevada-specific. It's the trade licensing exam issued through the Nevada State Contractors Board and delivered by PSI Services LLC - it isn't a national credential and shouldn't be confused with other programs that share the same acronym.
No. NV-C1 is the full C-1 Plumbing and Heating Contractor exam covering both trades. C-1d is a narrower, plumbing-only version. Confirm with the Board which classification your application targets before you start studying.
The exam has 120 scored questions with a five-hour time limit. You need 84 correct answers, equal to 70%, to pass. PSI may also insert up to 10 unscored experimental questions that use exam time but aren't graded.
No. You may bring only the five approved references - UPC 2018, UMC 2018, NFPA 54 (2012), NFPA 58 (2014), and NFPA 13 (2019) - with advance highlighting, underlining, and permanent tabs. Handwritten notes, loose papers, and temporary tabs are prohibited.
You must wait two weeks before retesting. If you fail three times, your application is voided and you'll need to reapply through the Nevada State Contractors Board from the beginning.