Free practice questions for Arizona's C-37 / CR-37 Plumbing (Commercial) trade exam — 100 questions on the 2018 IPC, fuel gas, hydronics, sprinklers and septic — with a written explanation on every answer, in English, Spanish, and Russian.
8 questions, about 4 minutes. No account needed — pick an answer to see whether it's right and read the explanation, the same explanations you get on every question in the full course.
Practice across the full question bank.
Each explanation shows why the correct answer works.
Spend more time on the questions you miss.
Practice under exam-style time pressure before exam day.
Every question tells you why the correct answer is correct and defines the terms it uses — so you learn the rule, not just the answer.
Questions are written from scratch against the official codes and agency publications for this exam — never copied from the real exam.
Every question and explanation is fully translated, with the English exam term kept alongside — not a shallow machine translation.
LICENA is a practice tool, not a school. We don't promise a pass — we help you understand the material and walk in prepared.
The full Arizona C-37 / CR-37 course is 500 questions across 5 blocks written to the exam's own references — the 2018 IPC, IFGC and IMC, NFPA 13, 29 CFR 1926 and Arizona's on-site wastewater rules — every answer cited to its section.
Exam structure, topics, study areas and official resources.
The C-37 / CR-37 Plumbing (Commercial) exam is PSI's trade test for Arizona's commercial plumbing licenses: 100 questions, 240 minutes, 70 percent to pass, open book. The references allowed in the exam center include the 2018 International Plumbing, Fuel Gas and Mechanical Codes, NFPA 13 and OSHA's 29 CFR 1926. Try the free sample above: no sign-up, with a written explanation on every question.
PSI's L-37 Plumbing (Commercial) content outline (rev. 1/20/2022), linked from the Arizona bulletin for both C-37 and CR-37, sets the format: 100 questions, 240 minutes, 70 percent, open book. The references allowed in the exam center are the 2018 International Plumbing Code, International Fuel Gas Code and International Mechanical Code, NFPA 13 (2016) with NFPA 13D and 13R (2007), 29 CFR 1926 for jobsite safety and the on-site wastewater provisions of A.A.C. Title 18, Chapter 9. Code questions are based on the listed editions, so study the 2018 codes even though newer editions exist. Books may be highlighted and tabbed with permanent tabs beforehand, but not written in during the exam; a non-programmable calculator is allowed.
The outline splits the exam into 13 areas. The heaviest is drainage, waste and vents (15), followed by water supply systems (12), septic and sewer (11), fuel gas (11) and general knowledge (8). Plumbing fixtures, water heaters and accessibility, hydronics, fire sprinklers and excavation carry six questions each; roof drains and storm drainage, specialty plumbing, interceptors and traps, and backflow prevention five each; indirect waste four. Commercial work shows up in the arithmetic and the scenarios: fixture counts from Table 403.1, drain and vent sizing by fixture units, storm drainage for large roofs with secondary overflow drains, grease and oil interceptors, gas test pressures at 1½ times the working pressure.
C-37 is Arizona's commercial plumbing classification and CR-37 the dual residential-and-commercial license; the Arizona bulletin links both to the same L-37 outline, so both take this one PSI exam. Residential-only plumbing is the separate R-37R license with its own exam. Beyond the pipe, the outline reaches the site: OSHA's Subpart P excavation rules for trench work and Arizona's on-site wastewater rules for septic systems. Every Arizona license also requires the SRE, AZ ROC's separate open-book law exam; the trade exam tests none of that statute material, so budget for both preparations.
The full LICENA course is 500 questions in five blocks, every answer explained with its code citation. At 30 questions a day that is under three weeks: a first pass to find what you do not know, a second on weak blocks, then the timed final mirroring the real 100-question, 240-minute format. Open book rewards navigation — knowing that fixture counts are Table 403.1, drainage slope is Table 704.1, interceptors are Section 1003, secondary roof drains are 1108 and gas pipe testing is IFGC 406 — and drilling builds that reflex. Pair the bank with the Arizona SRE practice (also required) and our guide to Arizona's contractor exams.
Try the full bank free for 3 days — no card needed. Then $9.99 for your first month and $19.99/month after that if you decide to continue, cancel anytime. A school sells a full prepaid package; this is a question bank you can stop at any time — and you study on your phone, in your language, whenever you have a few minutes.
Continue Arizona C-37 practice The free sample above stays free. Creating an account is free — no card needed.LICENA gives you practice questions to study with. We are not an accredited school and we do not guarantee that you will pass any exam.
LICENA provides online practice only. Registration, testing and licensing are handled by the Arizona Registrar of Contractors (AZ ROC) and PSI — not by LICENA. LICENA is not affiliated with AZ ROC or PSI.