Arizona licenses plumbing through the Registrar of Contractors (ROC) specialty classifications — C-37 Plumbing for commercial work and CR-37 Plumbing as the dual classification at the top of the family, with R-37 Plumbing, Including Solar and R-37R Plumbing as the residential classes of the same program. The license belongs to the business; the examinations are taken by the business’s qualifying party, who must receive a grade of at least 70% on each required examination. The PassProfessor Arizona program prepares qualifying parties for the C-37, CR-37, and R-37 trade examinations and the separate R-37 solar portion, all tested on the 2018 editions of the national plumbing, fuel gas, and mechanical codes.
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A contractor classification family, not a personal license ladder
Arizona’s plumbing credential does not work the way a personal trade license works, and every part of this page follows from that difference. The Registrar of Contractors issues specialty contractor classifications to businesses. The C-37 family contains four classifications: C-37 Plumbing, the specialty commercial classification; CR-37 Plumbing, the specialty dual classification; R-37 Plumbing, Including Solar, a specialty residential classification; and R-37R Plumbing, a restricted specialty residential classification. The top examined tier — the tier this program is built around — is the commercial and dual pair, C-37 and CR-37, which share a single PSI content outline titled for both.
The license itself belongs to the business, not to the person who examines for it, and it is non-transferable. Examinations are taken by the qualifying party: the person responsible for the licensee’s actions and conduct under the license, who either holds an ownership interest in the licensee or is regularly employed by it. When a candidate sits an Arizona plumbing examination, they are qualifying a business’s license. Arizona issues no statewide individual plumbing license beneath or above this family; the qualifying-party system is the ladder.
Scope pairings in this family must be stated exactly, because one pairing is commonly gotten wrong. The dual classification, CR-37, allows the scopes of the commercial C-37 license and the residential R-37R license — CR-37 pairs C-37 with R-37R, not with R-37. The residential classification that includes solar work is R-37, whose solar component is examined separately, as described below. Neither the C-37 nor the R-37 published scope states a maximum project dollar amount.
The examinations at a glance
| Item | Verified position |
|---|---|
| Program | Arizona ROC C-37 Plumbing (commercial) / CR-37 Plumbing (dual) — one program with the residential classes R-37 Plumbing, Including Solar and R-37R Plumbing |
| Regulator | Arizona Registrar of Contractors (ROC) |
| License holder | The business. Examinations are taken by the qualifying party |
| Passing standard | The qualifying party must receive a grade of at least 70% on each required examination (A.A.C. R4-9-106(C)) |
| C-37 / CR-37 trade examination | 100 items / 240 minutes / open book with candidate-supplied references, via PSI |
| R-37 trade examination | 100 items / 240 minutes / open book with candidate-supplied references, via PSI |
| R-37 solar portion | A separate examination: 30 items / 75 minutes; its only allowed in-room reference is the 2018 International Plumbing Code |
| R-37R | A classification of this program; its examinations are taken by the qualifying party under the same rule standard above |
| Hands-on practical | None for any classification in this family |
| Drawing component | Isometric Analysis appears only in the R-37 outline, as 5 items inside the written examination; the C-37 (CR-37) outline has no isometric topic |
| Tested codes | International Plumbing Code, 2018 Edition; International Fuel Gas Code, 2018 Edition; International Mechanical Code, 2018 Edition |
| Adopted code layer | Arizona has no statewide adopted plumbing code. Adoption is local, and both IPC and UPC jurisdictions exist in Arizona |
| Business-law requirement | The AZ Statutes and Rules Training Course and Exam (SRE), delivered online through GMetrix — a separate requirement, stated for structure only |
| Examination fees | PSI: one examination $66; two examinations $116; solar portion only $40 |
| Administrator note | PassProfessor is independent and is not affiliated with the Arizona Registrar of Contractors |
The trade examinations: same size, different outlines
The commercial and residential trade examinations look identical from a distance — each is 100 items in 240 minutes, computer-based through PSI, open book with candidate-supplied references — and they are not the same examination in content. Treating the two outlines as interchangeable is the family’s signature preparation error.
The C-37 (CR-37) outline, last revised January 20, 2022, distributes its 100 items as follows: Drainage, Waste and Vents, 15; Water Supply Systems, 12; Fuel Gas, 11; Septic and Sewer, 11; General Knowledge, 8; Plumbing Fixtures, including water heaters and accessibility, 6; Hydronics, 6; Fire Sprinklers, 6; Excavation, 6; Backflow Prevention, 5; Roof Drains and Storm Drainage Systems, 5; Specialty Plumbing, Interceptors, and Traps, 5; and Indirect Waste, 4. The commercial outline contains no Isometric Analysis topic.
The R-37 outline, last revised June 8, 2023, distributes its 100 items differently: Drainage, Waste and Vents, 16; Water Supply Systems, 13; Septic and Sewer, 10; General Knowledge and General Regulations, 10; Fuel Gas, 10; Plumbing Fixtures, including water heaters and accessibility, 7; Backflow Prevention, 5; Roof Drains and Storm Drainage Systems, 5; Specialty Plumbing, Interceptors, and Traps, 5; Isometric Analysis, 5; Fire Sprinklers, 5; Excavation, 5; and Indirect Waste, 4. The residential outline has no Hydronics topic, and it adds the Isometric Analysis block the commercial outline does not have — five items of drawing interpretation inside the written examination. There is no hands-on practical examination for any classification in this family; the R-37 isometric items are the family’s only drawing component, and they belong to the residential sitting alone.
The R-37 solar portion is a separate examination in its own right: 30 items in 75 minutes, covering pool systems, estimating and sizing, collectors, controls, loop systems, pipes and materials, system designs, and pumps and storage, with the 2018 International Plumbing Code as its only allowed in-room reference. A qualifying party for R-37 prepares for two sittings, not one sitting with a solar chapter.
Reference-room details also differ between the outlines, and candidates should build their book sets per outline rather than per habit: certain sprinkler references are pinned to different editions between the commercial and residential lists, and one Arizona on-site wastewater reference allowed in the residential room is listed as not allowed in the commercial room. Across both examinations, references may be highlighted, underlined, annotated, or indexed before the examination and tabbed with permanent tabs only; no writing in references during the examination, and no loose papers. A silent, non-printing, non-programmable calculator is allowed. Each examination includes 5 to 10 unscored experimental questions that count against the candidate’s time.
Tested on 2018; adopted nowhere statewide
The trade examinations test the 2018 editions of three national codes: the International Plumbing Code, the International Fuel Gas Code, and the International Mechanical Code. Code questions are based only on the listed editions; other, non-code references may be used in later editions.
The adopted layer is the sharpest code fact in Arizona, and it must be stated exactly: Arizona has no statewide adopted plumbing code. Adoption is local, and both IPC and UPC jurisdictions exist in Arizona. There is no state code book to study instead of the examination list, and no local code — however familiar from daily work — composes the examination. Preparation built from a locally adopted code, from the Uniform Plumbing Code, or from a newer edition of the national plumbing code is preparation for a sitting Arizona does not give. This program is composed to the examination layer only: the 2018 editions named in the PSI outlines.
The qualifying party: eligibility without a ladder
Before a license is issued, the qualifying party must have a minimum of four years of practical or management trade experience dealing specifically with the type of construction applied for, at least two of which must have been within the last ten years. Technical training in an accredited college or university, or in a manufacturer’s accredited training program, may be substituted for a portion of that experience, but credited technical training may not exceed two years of the required four. Qualification must be shown by written examination taken not more than two years before application, and after passing, the candidate submits the completed license application and the original score report to the ROC within two years of passing.
Waiver positions soften the edges of that system for people already inside it. The Registrar shall waive the work-experience documentation requirement where the qualifying party is or has previously been a qualifying party in Arizona in the same classification, and shall waive the examination requirement where the qualifying party held that position in the same classification within the preceding five years. Arizona has no direct reciprocity with other states; the Registrar may waive the trade examination for an out-of-state qualifying party in the same or a comparable classification within the preceding five years, requested with the license application, with no pre-approval. Across the application, every person listed must be 18 years of age or older, every person named must complete a criminal background check through the ROC’s vendor, valid for 90 days, with a government-issued photo ID supplied, and a corporation or limited liability company applicant must be registered with the Arizona Corporation Commission and in good standing before applying and to renew. A contractor’s license is generally required where labor and materials exceed $1,000, or where a permit is required regardless of price, and contractors must be licensed before submitting bids.
The business-law requirement, stated for structure only
Separate from the trade examinations, Arizona requires the AZ Statutes and Rules Training Course and Exam — the SRE — delivered online only through GMetrix, self-paced, computer-based and open book, with testing throughout the training, at a cost of $61. It is required for applicants who have not previously been listed as the qualifying party on another Arizona contractor license within the last five years. This program covers the trade examinations; the SRE is recorded here so no qualifying party mistakes a trade pass for a completed application. Any source describing a PSI business examination for Arizona as a current requirement is describing an obsolete examination; the SRE through GMetrix is the business-law requirement as it stands.
The dollars, by layer
PSI examination fees are $66 for one examination, $116 for two examinations, and $40 for the solar portion only; fees are not refundable or transferable, and a paid fee is valid for one year. The SRE costs $61, paid to GMetrix. ROC license figures are two-year totals and exclude examination fees: for an initial license, C-37 totals $580; R-37 and R-37R each total $720; and CR-37 totals $850. Renewal figures for the two-year term are $480 for the commercial classification; $540 for the residential classifications ($270 license plus $270 recovery fund); and $650 for the dual classification ($380 plus $270). A $50 fee applies to a late renewal. A surety bond — or a cash deposit in its place — is required before an original license is granted and must remain in full force and effect for renewal; renewal also requires verifying that the bond is active and covers the licensee’s annual volume, with a bond rider required where volume has increased, and supplying the workers’ compensation policy number and issuer where the licensee has employees.
Retakes run on a stated schedule: a candidate who fails must wait 30 days before retaking, three attempts are allowed, and a fourth and subsequent attempts require a 90-day wait between schedules. The governing rule states the same waits per failure — 30 calendar days from the first failure, 30 calendar days from the second, and 90 days from any other failure. Candidates arrive 30 minutes early with one form of valid, unexpired, signature- and photo-bearing identification, may take a tutorial of up to 15 minutes that does not count against examination time, see the score displayed on screen at the end, and receive an emailed diagnostic report after a failure. Canceling or rescheduling without forfeiting the fee requires notice received 2 days before the appointment, by an accepted method — voicemail and email are not acceptable cancellation methods — and a missed appointment, late arrival, or lack of proper identification forfeits the fee.
Adjacent to this family, the ROC also lists the solar classifications C-77 Plumbing, Including Solar, CR-77 Plumbing, Including Solar, and C-78 Solar Plumbing, Liquid Systems Only, named here as classifications only; candidates for them should confirm their requirements directly with the ROC.
What the PassProfessor program will cover
The Arizona program in the PassProfessor catalog is composed per outline, not per state average. Commercial and dual qualifying parties prepare against the C-37 (CR-37) outline — its hydronics weight, its heavier fuel gas and septic blocks, and no isometric component, because that outline contains none. Residential qualifying parties prepare against the R-37 outline — its isometric block, its regulations weight, and its reference-room differences — plus the separate solar portion, treated as its own sitting with its own outline and single in-room reference. Both tracks are composed to the 2018 editions named in the outlines, and neither borrows content from a locally adopted Arizona code or any other code family. The companion guide at /arizona-master-plumber-exam-guide/ walks the family and the two outlines side by side in depth.
Independence, stated plainly. PassProfessor is an independent preparation provider, not affiliated with the Arizona Registrar of Contractors, PSI, or GMetrix. Completing this program confers no license; the ROC alone licenses.
Tell me when enrollment opens. The Arizona ROC C-37 Plumbing and CR-37 Plumbing (Dual) program is in the works and enrollment is not yet open. Leave an email address and PassProfessor will write to you when the program is ready — and only about this program.
Frequently asked questions
What does the dual classification, CR-37, pair together?
The scopes of the commercial C-37 license and the residential R-37R license. CR-37 pairs C-37 with R-37R — not with R-37.
What score must the qualifying party receive?
A grade of at least 70% on each required examination, under A.A.C. R4-9-106(C).
How are the C-37 and R-37 examinations structured?
Each is 100 items in 240 minutes, open book with candidate-supplied references, delivered by PSI. Their content outlines differ: the commercial outline includes Hydronics and has no isometric topic; the residential outline includes Isometric Analysis, 5 items, and no Hydronics topic.
Is there a hands-on practical?
No. There is no hands-on practical examination for any classification in this family. The only drawing component is the R-37 outline’s Isometric Analysis block, inside the written examination.
Which codes are tested?
The 2018 editions of the International Plumbing Code, the International Fuel Gas Code, and the International Mechanical Code.
Which plumbing code has Arizona adopted statewide?
None. Arizona has no statewide adopted plumbing code; adoption is local, and both IPC and UPC jurisdictions exist in Arizona. The examinations test the 2018 editions listed in the PSI outlines regardless of local adoption.
When does enrollment open?
The program is in the works and enrollment is not yet open. Leave an email address on this page and PassProfessor will write to you when the program is ready — and only about this program.