- What Is the NV-C1 Certification?
- How Registration and Board Approval Work
- Exam Format: Questions, Timing, and Scoring
- The 23 NV-C1 Domains and How They're Weighted
- Approved References and Exam-Day Materials
- NV-C1 Exam Cost and Licensing Fees
- Eligibility: Experience and Education Requirements
- Retake Policy and What Happens If You Fail
- Building a Domain-Weighted Study Plan
- Who Hires C-1 Licensed Contractors in Nevada
- Frequently Asked Questions
- The C-1 trade exam has 120 scored questions, a five-hour limit, and requires 84 correct (70%) to pass.
- PSI charges $95 for a single exam portion 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.
- Only five references are permitted in the testing room: UPC 2018, UMC 2018, NFPA 54 (2012), NFPA 58 (2014), and NFPA 13 (2019).
What Is the NV-C1 Certification?
The Nevada Plumbing and Heating Contractor (C-1) Trade Exam is the full trade-competency test administered by PSI Services LLC on behalf of the Nevada State Contractors Board. It is broader than the C-1d plumbing-only examination, covering the entire scope of plumbing and heating contracting work a licensed C-1 contractor performs in the field. Passing this exam is one piece of qualifying for a C-1 contractor license; the other is the separate Contractor Management Survey (CMS), a business-and-law exam with its own 75% passing standard that should never be confused with the trade content covered here.
If you're still getting oriented, the companion piece What Is NV-C1? and NV-C1 Meaning walk through the terminology in more depth, while What Does NV-C1 Stand For? clarifies how the acronym maps to the license classification itself.
How Registration and Board Approval Work
Before you can sit for the exam, the Nevada State Contractors Board must approve your license application. This approval step happens first - scheduling with PSI only becomes available once the Board has cleared your application. Candidates who skip ahead and try to book a PSI slot without Board approval will find themselves stuck.
Once approved, you work directly with PSI Services LLC to schedule a computer-administered, open-book test session. The exam is delivered on-screen, timed, and proctored at a PSI test center, so familiarity with the computer interface matters as much as familiarity with code content. For a full walkthrough of the qualification steps that precede scheduling, see NV-C1 Requirements 2026: Eligibility, Prerequisites & How to Qualify.
Exam Format: Questions, Timing, and Scoring
The C-1 trade exam consists of 120 scored questions with a five-hour time limit. To pass, a candidate must answer 84 questions correctly, which equals the required 70% passing standard. PSI may also insert between 1 and 10 unscored, experimental questions into the exam; these questions look identical to scored items but do not count toward your final result - however, they do count against your five-hour clock, so pacing matters even though you can't tell which questions are experimental.
The test is open-book, but "open-book" here means a strictly limited set of five approved references, not any code book you own. It is also computer-administered, so candidates should practice navigating on-screen question formats, flagging items for review, and managing time across 120 questions rather than relying purely on paper test-taking habits.
Key Takeaway
Budget your five hours around 120 scored questions plus up to 10 unscored ones - that's roughly two to two-and-a-half minutes per question if you want time left over for review.
For a deeper breakdown of exactly how the passing threshold is calculated and why 84 out of 120 is the magic number, read NV-C1 Passing Score 2026: Exactly What You Need to Pass. If you want a broader sense of how tough the exam feels in practice, How Hard Is the NV-C1 Exam? Complete Difficulty Guide 2026 and NV-C1 Pass Rate 2026: What the Data Shows go into more detail.
The 23 NV-C1 Domains and How They're Weighted
The PSI bulletin (updated March 25, 2026) breaks the 120 scored questions into 23 domains, each with a specific item count. Understanding this distribution is the single most useful thing you can do before you open a study guide, because it tells you exactly where to spend your limited prep time.
| Domain | Item Count |
|---|---|
| Boilers | 4 |
| Gas Systems | 8 |
| Cleanouts | 4 |
| Fixtures and Equipment | 4 |
| Hydronics | 3 |
| Water Heaters/Venting | 6 |
| Piping, Valves, and Controls | 3 |
| Sheet Metal | 3 |
| Water Supply | 8 |
| Hangers and Supports | 5 |
| Drain, Waste, and Vents | 10 |
| Backflow | 4 |
| Traps and Interceptors | 8 |
| Isometric Analysis/Plumbing Mathematics | 8 |
| Safety | 5 |
| Joints and Connections | 4 |
| Solar | 4 |
| General Plumbing Requirements | 7 |
| Fire Sprinklers | 5 |
| Storm Drainage | 5 |
| Industrial Piping | 3 |
| Breathing Systems for Firefighters | 3 |
| Chilled Water Piping | 6 |
Drain, Waste, and Vents is the single largest domain at 10 items, so it deserves the most concentrated review. Gas Systems, Water Supply, Traps and Interceptors, and Isometric Analysis/Plumbing Mathematics tie for second-heaviest at 8 items each - meaning these five domains alone account for 42 of the 120 scored questions, well over a third of the exam.
Drain, Waste, and Vents (10 items)
As the largest single domain, candidates should be comfortable with sizing, slope requirements, venting configurations, and fixture unit calculations as they apply to DWV systems.
- Practice fixture-unit-to-pipe-size conversions until they're automatic
Isometric Analysis/Plumbing Mathematics (8 items)
This domain tests your ability to read isometric drawings and apply plumbing math under time pressure - a skill that benefits from repeated practice with real diagrams rather than memorized formulas alone.
- Work through isometric read-and-solve problems using only the approved code references
The smallest domains - Hydronics, Piping/Valves/Controls, Sheet Metal, Industrial Piping, and Breathing Systems for Firefighters - carry just 3 items each. That doesn't mean you can ignore them; a candidate who skips five domains entirely gives up 15 potential points, more than enough to turn a passing score into a failing one. For a domain-by-domain narrative rather than a table, see NV-C1 Exam Domains 2026: Complete Guide to All 23 Content Areas.
Approved References and Exam-Day Materials
Because the exam is open-book, what you're allowed to bring into the testing room is as important as what you know. The five approved examination-room references are:
- 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
These are the only books permitted in the room. The PSI bulletin also references separate study materials used for exam preparation that are explicitly not allowed at the test center - don't confuse a study reference with an admitted reference, because bringing the wrong edition or an unlisted study guide can create problems at check-in.
You are allowed to prepare your reference books in advance with highlighting, underlining, and permanent tabs. What you cannot bring are handwritten notes, loose papers, or temporary tabs (like sticky flags that peel off). A silent, nonprinting, nonprogrammable calculator without an alphabetic keyboard is also permitted, which matters for the math-heavy Isometric Analysis/Plumbing Mathematics domain.
A dedicated breakdown of exactly which editions to buy and how to organize them is available in Nevada C-1 exam books resources and the broader NV-C1 Study Guide 2026: How to Pass on Your First Attempt.
NV-C1 Exam Cost and Licensing Fees
Understanding the fee structure helps you budget for the whole licensing process, not just the exam itself:
- PSI charges $95 for a single examination portion, or $140 when the C-1 trade exam is paired with the CMS business-and-law exam in the same sitting.
- The Nevada State Contractors Board charges a $300 application fee.
- An initial two-year license costs $600, and biennial renewal is also $600 each cycle.
These fees apply regardless of how many attempts it takes to pass the exam itself, so factor retake costs into your planning. A full cost breakdown, including how the application fee, exam fee, and license fee stack together over a two-year cycle, is available in NV-C1 Certification Cost 2026: Complete Pricing Breakdown.
Eligibility: Experience and Education Requirements
To qualify to sit for the C-1 trade exam, the trade qualifier ordinarily needs 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, but at least some hands-on qualifying experience is still expected.
Beyond experience, applicants must also satisfy financial, bond, and applicable insurance requirements set by the Board. These aren't part of the trade exam content, but they're conditions the Board reviews before granting the approval you need to schedule your PSI appointment. For the complete eligibility checklist, see NV-C1 Requirements 2026: Eligibility, Prerequisites & How to Qualify.
Retake Policy and What Happens If You Fail
If you don't pass on your first attempt, Nevada's rules require a two-week waiting period before you can retake the exam. This waiting period applies per failed attempt, so plan your study timeline accordingly rather than assuming you can retest immediately.
Key Takeaway
Three failed attempts void your application entirely, meaning you'd need to start the Board approval process over. Treat each attempt seriously and use the two-week gap for focused review of your weakest domains.
Because a voided application means repeating the Board approval step and re-paying associated fees, most candidates find it worthwhile to over-prepare rather than treat the exam as low-stakes practice.
Building a Domain-Weighted Study Plan
Rather than studying all 23 domains equally, allocate your time in proportion to their item counts. A simple, focused approach works better than generic study hacks borrowed from unrelated certifications.
Heaviest Domains
- Drain, Waste, and Vents (10 items) - sizing, slope, venting
- Gas Systems and Water Supply (8 items each)
Math and Interceptors
- Isometric Analysis/Plumbing Mathematics (8 items) - practice with your approved calculator
- Traps and Interceptors (8 items)
Mid-Weight Domains
- General Plumbing Requirements (7), Chilled Water Piping (6), Water Heaters/Venting (6)
- Hangers and Supports, Safety, Fire Sprinklers, Storm Drainage (5 each)
Lighter Domains and Full Reviews
- Boilers, Cleanouts, Fixtures, Backflow, Joints, Solar (4 each)
- Hydronics, Piping/Valves/Controls, Sheet Metal, Industrial Piping, Breathing Systems for Firefighters (3 each)
- Full timed practice run under the five-hour limit
Time-block your review sessions and use timed practice sets that mirror the 120-question, five-hour format so pacing feels familiar on exam day. The NV-C1 Cheat Sheet 2026: One-Page Review of Must-Know Facts is a useful quick-reference during your final week, and running full-length simulations on the practice test platform will help you gauge readiness against the real domain weighting before you schedule your PSI appointment.
Who Hires C-1 Licensed Contractors in Nevada
A C-1 license from the Nevada State Contractors Board qualifies you to operate as a plumbing and heating contractor across the full scope covered by the trade exam's 23 domains - from gas systems and water heaters to fire sprinklers and chilled water piping. This breadth means licensed C-1 contractors are positioned for residential, commercial, and mixed-use plumbing and heating work rather than a single narrow specialty.
If you're weighing whether pursuing this license makes sense for your career, Is the NV-C1 Certification Worth It? Complete ROI Analysis 2026 and NV-C1 Salary Guide 2026: Complete Earnings Analysis explore the return on the licensing investment in more depth, while NV-C1 Jobs looks at the kinds of roles this license opens up.
Once licensed, remember that renewal happens every two years at $600 per cycle, and ongoing bond and applicable insurance compliance must be maintained throughout - the exam is a gateway, but the license requires continued upkeep. See NV-C1 Training and What Is NV-C1 Certification? for more on maintaining and building on your credential after you pass.
Frequently Asked Questions
No. The C-1 trade exam covers the full plumbing and heating contractor scope across 23 domains, while the C-1d exam is limited to plumbing-only content. This article covers the full C-1 trade exam specifically.
There are 120 scored questions with a five-hour time limit. PSI may add 1 to 10 unscored experimental questions that count against your time but not your score.
You need 84 correct answers out of 120 scored questions, which equals 70%.
No. Handwritten notes, loose papers, and temporary tabs are prohibited. Only the five approved references with advance highlighting, underlining, and permanent tabs are allowed, along with a compliant silent calculator.
You must wait two weeks before retesting. If you fail three times, your application is voided and you'll need to restart the Board approval process.