Arizona's Registrar of Contractors does not issue one generic "contractor" license. It issues a class, and the class is the legal scope of the work the firm may contract. The official descriptions live on the ROC license classifications page. This page is a reading guide for that list, using the classes that actually show up in the 2026-07-01 snapshot we hold.
Read the prefix first
| Prefix | Scope | Typical use |
|---|---|---|
| R- | Residential | Houses, townhouses, condos, and work inside residential property lines |
| C- | Commercial | Anything the ROC defines as not residential |
| CR- | Dual | The same trade on both sides |
The ROC's own page states the split that way: residential contracting is houses and their appurtenances, and commercial contracting is everything else. A dual class is the residential class plus the commercial class for that trade, not a third kind of work.
General licenses sit outside that specialty pattern. On the 2026-07-01 snapshot the largest general classes are KB-2 Dual Residential and Small Commercial (4,195 licenses), B General Residential Contractor (3,837), KB-1 Dual Building Contractor (3,447), and B-1 General Commercial Contractor (2,947). Those firms can contract a wide range of work, often by hiring licensed specialty subs. That is a different fact from "this firm is a roofer."
Common specialty classes for a homeowner hire
Counts are distinct active, unexpired licenses on the 2026-07-01 snapshot, for that exact class token.
| Class | Class detail on the file | Active licenses | Hire this for |
|---|---|---|---|
| CR-11 | Electrical | 2,917 | Electrical work that spans residential and commercial |
| R-11 | Electrical | 722 | Residential electrical only |
| C-11 | Electrical | 1,230 | Commercial electrical only |
| CR-37 | Plumbing | 2,049 | Plumbing on both sides |
| R-37R | Plumbing | 701 | Residential plumbing |
| CR-39 | Air Conditioning and Refrigeration | 2,847 | HVAC |
| CR-42 | Roofing | 1,326 | Roofing |
| CR-21 | Hardscaping and Irrigation Systems | 1,928 | Hardscape and irrigation |
| KA-5 | Dual Swimming Pool Contractor | 401 | Pool construction (dual) |
| CR-6 | Swimming Pool Service and Repair | 365 | Pool service and repair, not new construction |
Across every electrical class token we count (CR-11, C-11, R-11) there are 4,869 distinct active licenses. Plumbing (CR-37, C-37, R-37, R-37R) is 3,200. Roofing (CR-42, C-42, R-42) is 1,429. Those unions are the right denominator for "how many firms could legally do this trade," not the dual-only row.
Pool construction is a shorter bench than electrical or plumbing, and the class names matter: KA-5 / B-5 / A-9 are construction, CR-6 / R-6 / C-6 are service and repair.
How to use this on a quote
Ask for the license number and the class, then look both up on the ROC Contractor Search. The class on the record has to cover the job you described. A CR-11 does not make a firm a roofer. A KB-2 does not make a firm an electrician.
If we publish a ranking for that trade in your city, the live page already requires the matching class. Scottsdale electricians, Phoenix roofers, and Arizona trade hubs are current examples. Do not paste those lists here. They change when the snapshot and the permit feed move.
Where this guide does not help
Washington, or any board that does not encode scope in the class code. Work that is exempt from licensure under Arizona statute. Whether a dual-licensed firm will actually send the qualifying party. The official scope language for an edge-case class: that is the ROC page, not a paraphrase.