- What NV-C1 Actually Is
- Who Administers the Exam
- Exam Format and Scoring
- The 23 Domains That Make Up NV-C1
- Approved References and What You Can Bring
- Registration, Fees, and Retake Rules
- Who Qualifies to Sit for NV-C1
- Who Actually Takes This Exam
- Building a Study Plan Around the Blueprint
- Frequently Asked Questions
- NV-C1 is the full Nevada Plumbing and Heating Contractor trade exam, not the plumbing-only C-1d version.
- 120 scored questions, five-hour limit, 84 correct (70%) needed to pass.
- Drain, Waste, and Vents carries the most weight at 10 of 120 items.
- Only five references are allowed in the room: UPC 2018, UMC 2018, NFPA 54 (2012), NFPA 58 (2014), and NFPA 13 (2019).
What NV-C1 Actually Is
NV-C1 refers to the Nevada Plumbing and Heating Contractor (C-1) Trade Exam, the full-scope trade competency test required by the Nevada State Contractors Board (NSCB) for applicants seeking a C-1 contractor license. It is important to be precise here: NV-C1 is the complete plumbing-and-heating exam, distinct from the narrower C-1d plumbing-only examination. Confusing the two can lead candidates to study the wrong scope entirely, since the full C-1 exam pulls from mechanical, hydronic, and gas-related domains that C-1d does not cover.
If you're just getting oriented, our companion pieces on NV-C1 Meaning and What Does NV-C1 Stand For? go deeper into the terminology, while this article focuses on how the exam is structured and administered.
Who Administers the Exam
The Nevada State Contractors Board sets licensing policy and eligibility rules, but the trade exam itself is delivered through PSI Services LLC, a third-party testing vendor. Board approval of your application must happen first - you cannot simply register and sit for the exam. Once the Board clears your qualifications, you schedule your test session through PSI.
Exam Format and Scoring
The NV-C1 trade exam consists of 120 scored questions delivered in a computer-administered, open-book format, with a five-hour time limit. To pass, you need 84 correct answers, which equals 70%. PSI may insert between 1 and 10 additional unscored experimental questions into your session - these look identical to scored items, and they count against your five-hour clock even though they don't count toward your score. That means the number of questions on your screen may be slightly higher than 120, but the passing threshold is always calculated against the 120 scored items.
Since it's open-book, the exam is less about memorizing code verbatim and more about knowing where to find answers quickly and understanding how to apply formulas and code sections under time pressure. For a deeper breakdown of what "passing" really means numerically, see NV-C1 Passing Score 2026: Exactly What You Need to Pass.
Key Takeaway
Budget your five hours against 120+ questions - roughly two to two-and-a-half minutes per question - and don't let unscored experimental items throw off your pacing since you can't identify which ones they are.
The 23 Domains That Make Up NV-C1
The PSI bulletin (updated March 25, 2026) defines 23 content domains with fixed item allocations that sum to 120 questions. Understanding this weighting is the single most useful thing you can do before opening a study guide, because it tells you exactly where your study hours will pay off.
| Domain | Items |
|---|---|
| Drain, Waste, and Vents | 10 |
| Gas Systems | 8 |
| Water Supply | 8 |
| Traps and Interceptors | 8 |
| Isometric Analysis/Plumbing Mathematics | 8 |
| Fixtures and Equipment | 4 |
| Water Heaters/Venting | 6 |
| General Plumbing Requirements | 7 |
| Sheet Metal | 3 |
| Hangers and Supports | 5 |
| Backflow | 4 |
| Safety | 4 |
| Joints and Connections | 4 |
| Fire Sprinklers | 5 |
| Storm Drainage | 5 |
| Industrial Piping | 3 |
| Breathing Systems for Firefighters | 3 |
| Chilled Water Piping | 6 |
| Boilers | 4 |
| Cleanouts | 4 |
| Hydronics | 3 |
| Piping, Valves, and Controls | 6 |
| Solar | 3 |
Drain, Waste, and Vents (10 items)
This is the single largest domain on the exam. Candidates should be fluent in vent sizing, trap arms, cleanout placement logic as it interacts with DWV runs, and slope requirements per the UPC.
- Know minimum and maximum trap-arm distances by fixture
- Understand vent stack sizing tables and wet-venting rules
Gas Systems, Water Supply, Traps and Interceptors, Isometric Analysis/Plumbing Mathematics (8 items each)
These four domains are tied for second-largest weight. Gas Systems draws heavily on NFPA 54, Water Supply on UPC sizing charts, Traps and Interceptors on grease and oil interceptor sizing, and Isometric Analysis/Plumbing Mathematics on reading riser diagrams and performing load calculations.
- Practice converting isometric drawings into fixture-unit counts
- Memorize interceptor sizing based on flow rate and retention
Because 23 domains is a lot to internalize, we've built a full breakdown of every content area, including how each ties back to real-world plumbing and heating scope, in NV-C1 Exam Domains 2026: Complete Guide to All 23 Content Areas.
Approved References and What You Can Bring
Because this is an open-book exam, the reference materials you're allowed to bring matter as much as your underlying knowledge. PSI permits exactly five texts into the exam 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) - Standard for the Installation of Sprinkler Systems
The bulletin also lists study references used to build the exam that are not allowed into the room - don't confuse a study reference with an admitted reference; only the five above may physically sit next to you during testing.
A silent, nonprinting, nonprogrammable calculator without an alphabetic keyboard is permitted for the math-heavy sections like Isometric Analysis/Plumbing Mathematics. For a full rundown on which editions to buy and how to tab them, see Nevada C-1 exam books resources referenced throughout our study guide.
Registration, Fees, and Retake Rules
Two separate fee streams apply to NV-C1 candidates. The Nevada State Contractors Board charges a $300 application fee, and once licensed, an initial two-year license and each biennial renewal cost $600. Separately, PSI charges testing fees: $95 for a single exam portion or $140 when the trade exam is paired with the CMS business-and-law exam in one sitting.
If you fail an attempt, Nevada imposes a two-week mandatory wait before you can retest. More significantly, three failed attempts void your application entirely, meaning you'd need to start the Board application process over. That structure makes first-attempt preparation far more valuable than treating the exam as a low-stakes trial run. We break down the full cost picture, including how testing fees stack against license fees over a career, in NV-C1 Certification Cost 2026: Complete Pricing Breakdown.
Who Qualifies to Sit for NV-C1
Before you can schedule anything with PSI, the Board has to approve your application. The standard path requires four full years of qualifying journeyman, supervisory, or contractor experience within the preceding 15 years. Board-approved education can substitute for up to three of those four years, though experience alone remains the most common route for tradespeople. Applicants also need to satisfy financial, bond, and applicable insurance requirements before licensure is finalized - these aren't testing requirements per se, but they gate whether you can apply in the first place.
Because eligibility documentation trips up more applicants than the exam content itself, it's worth reading through NV-C1 Requirements 2026: Eligibility, Prerequisites & How to Qualify before you spend money on the PSI fee.
Who Actually Takes This Exam
NV-C1 is pursued by journeyman plumbers and heating technicians in Nevada who want to operate as licensed contractors - bidding jobs, pulling permits, and running crews rather than working under someone else's license. Because the exam covers boilers, hydronics, chilled water piping, fire sprinklers, and gas systems alongside core plumbing domains, it's aimed at people whose field experience already spans both plumbing and mechanical/heating scope, not plumbing-only specialists (who would instead pursue the narrower C-1d path).
Employers and job postings referencing "C-1 licensed" typically mean a contractor who has cleared this exact exam. If you're evaluating whether the license changes your job prospects or pay ceiling, our guides on NV-C1 Jobs and NV-C1 Salary Guide 2026: Complete Earnings Analysis lay out how the credential is used in the field.
Building a Study Plan Around the Blueprint
Generic study techniques only help once they're mapped onto NV-C1's actual weighting. Since Drain, Waste, and Vents alone accounts for 10 of 120 items, and Gas Systems, Water Supply, Traps and Interceptors, and Isometric Analysis/Plumbing Mathematics each carry 8, roughly a third of the exam sits inside just five domains. A reasonable plan front-loads those five before moving to mid-weight domains like General Plumbing Requirements (7), Water Heaters/Venting (6), Chilled Water Piping (6), and Piping, Valves, and Controls (6).
High-weight domains
- Drain, Waste, and Vents; Gas Systems; Water Supply
High-weight domains continued
- Traps and Interceptors; Isometric Analysis/Plumbing Mathematics
Mid-weight domains
- General Plumbing Requirements; Water Heaters/Venting; Chilled Water Piping; Piping, Valves, and Controls
Remaining domains and open-book drills
- Fire Sprinklers; Storm Drainage; Hangers and Supports; Boilers, Cleanouts, Backflow, Safety, Joints and Connections; full-length timed practice with your five approved references
Whatever cadence you use, spend real time practicing with the five approved references physically in hand, since navigating UPC 2018 and NFPA 54 quickly under a five-hour clock is a skill separate from knowing the material. For a full week-by-week methodology, read NV-C1 Study Guide 2026: How to Pass on Your First Attempt, and if you're still gauging difficulty relative to your background, How Hard Is the NV-C1 Exam? Complete Difficulty Guide 2026 walks through what makes each domain challenging.
Frequently Asked Questions
No. NV-C1 is the full Plumbing and Heating Contractor trade exam covering all 23 domains, including mechanical and heating content. C-1d is a narrower, plumbing-only examination and is not covered by this article.
There are 120 scored questions, plus possibly 1-10 unscored experimental questions. You need 84 correct answers, equal to 70%, to pass.
You must wait two weeks before retesting. If you fail three times, your application is voided and you'll need to reapply with the Board.
No. Handwritten notes, loose papers, and temporary tabs are prohibited. You may use advance highlighting, underlining, and permanent tabs in the five approved reference books only.
The CMS business-and-law exam is separate, with its own 75% passing standard. PSI allows you to pair it with the trade exam for a combined $140 fee, but it is scored independently.
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