Arizona C-37 Plumbing Contractor Exam Prep

About the Arizona C-37 Plumbing license

Arizona licenses plumbing contracting businesses through the Arizona Registrar of Contractors (ROC) — it does not license individual journeyman or master plumbers the way some states do. C-37 is the commercial plumbing contractor classification (its residential counterpart is R-37; CR-37 covers both). Every license is tied to a Qualifying Party — the individual whose documented trade experience and exam scores qualify the license — who must show at least four years of practical or supervisory/managerial plumbing experience (at the journeyman, foreman, supervisor, or contractor level), with at least two of those years within the last ten, and pass the required exams before the business can be licensed.

Your trade exam is built on the International Plumbing Code (IPC), 2018 Edition, per the current ROC/PSI candidate bulletin — plus the 2018 International Fuel Gas Code, the 2018 International Mechanical Code, and NFPA 13/13D/13R for the fire-sprinkler portion of the blueprint (L-37.pdf, last revised January 20, 2022: NFPA 13 is the 2016 edition, and NFPA 13D and NFPA 13R are the 2007 editions). Arizona is an IPC state, not a UPC state — a common mix-up, since neighboring California and Nevada use the Uniform Plumbing Code (UPC) published by IAPMO. The two model codes agree on the underlying physics but differ in tables, fixture-unit values, and some sizing methods, so don't bring UPC habits into an Arizona exam.

Know these scope facts cold: the license is held by the individual; most work requires a permit and inspection (rough-in/top-out and final); you must work within the classification you hold; and unlicensed or out-of-scope plumbing work is a violation that can cost you the license and carry penalties. Plumbing protects public health — the exam constantly returns to the two core purposes of the code: deliver safe potable water and remove waste without contaminating that water.

How Arizona licensing works

• Experience: the Qualifying Party documents at least 4 years of practical or supervisory/managerial plumbing experience (journeyman, foreman, supervisor, or contractor level); up to 2 of those years can be substituted with accredited technical training.
• Education: accredited plumbing/trade coursework can offset part — not all — of the 4-year experience requirement.
• Application: the Qualifying Party and the business entity apply together to ROC with fees, documented experience, and a license bond sized to anticipated annual volume, before the Qualifying Party is approved to sit for exams.
• Exams and vendor: the C-37/CR-37 trade exam is administered by PSI — 100 questions, 240 minutes, 70 percent to pass (100 questions, 240 minutes, and 70 percent on L-37.pdf, revised January 20, 2022). Separately, a new qualifying party generally must also complete Arizona's Statutes and Rules Exam (SRE), an ROC online course. The February 18, 2026 candidate bulletin prices that course at $61 and does not print an SRE question count or cut score. A waiver may be granted in specific conditions. The SRE is not this PSI trade exam.
• Renewal: licenses renew on a 2-year cycle. Arizona does not require continuing education for plumbing contractor classifications (unlike the electrical classes) — just keep the license bond in force and renewal fees current.