California Contractor License Types & Requirements
A plain-English guide to California contractor license classifications, including general contractor licenses, plumbing, electrical, mechanical, HVAC, refrigeration, boiler, and specialty trade licenses.
Overview: California Contractor License Categories
California contractor licenses are issued through the Contractors State License Board, commonly known as the CSLB. The license you need depends on the type of work you plan to advertise, bid, contract, and perform.
General Engineering
For fixed works, infrastructure, roads, grading, bridges, utilities, pipelines, and civil construction.
General Building
For buildings and structures requiring at least two unrelated building trades or crafts.
Residential Remodeling
For nonstructural remodeling of existing residential wood-frame structures.
Specialty Contractor
For single-trade specialty work such as plumbing, electrical, HVAC, roofing, concrete, and more.
California General Contractor License Types
Class A — General Engineering Contractor
A Class A General Engineering Contractor license is for contractors whose principal work involves fixed works requiring specialized engineering knowledge and skill. This usually applies to heavy civil, infrastructure, utility, grading, excavation, roadway, bridge, pipeline, sewer, drainage, and public works construction.
Class B — General Building Contractor
A Class B General Building Contractor license applies to structures built for the support, shelter, or enclosure of people, animals, or property. This license is commonly used by contractors building homes, additions, commercial buildings, and larger multi-trade projects.
Class B-2 — Residential Remodeling Contractor
A B-2 Residential Remodeling Contractor license is for nonstructural remodeling work on existing residential wood-frame structures. It can apply to projects like kitchens, bathrooms, interior remodeling, cabinets, flooring, painting, drywall repair, and fixture replacement.
The B-2 classification has limits. It generally does not allow structural changes to load-bearing portions of the home, and it does not allow major electrical, mechanical, or plumbing system work unless the contractor holds the proper specialty classification or subcontracts that work to a properly licensed contractor.
Plumbing, Electrical & Mechanical Contractor Licenses in California
| Trade | License | What It Covers |
|---|---|---|
| Plumbing | C-36 | Safe water supply, plumbing systems, fluid waste disposal, fixtures, drains, and related plumbing work. |
| Electrical | C-10 | Electrical wires, fixtures, appliances, raceways, conduits, electrical equipment, and solar photovoltaic electrical components. |
| Low Voltage | C-7 | Low-voltage systems. This is separate from the broader C-10 electrical contractor classification. |
| HVAC | C-20 | Warm-air heating, ventilating, and air-conditioning systems. |
| Refrigeration | C-38 | Refrigerators, refrigerated rooms, walk-in coolers, freezers, insulated refrigerated spaces, and temperature-control systems below 50°F. |
| Boiler / Steam / Hot Water | C-4 | Boilers, hot-water heating systems, steam fitting, and related heating equipment. |
| Sheet Metal | C-43 | Sheet metal fabrication, installation, duct-related work, and related metal systems. |
C-36 Plumbing Contractor License
The C-36 Plumbing Contractor license is the main California plumbing contractor classification. It is used for contractors who install, repair, replace, or work on plumbing systems that provide safe water and dispose of waste from structures and fixed works.
C-10 Electrical Contractor License
The C-10 Electrical Contractor license is the main electrical contractor license in California. It applies to contractors who install, connect, or work with electrical wiring, fixtures, conduits, raceways, appliances, and equipment that generate, transmit, transform, or use electrical energy.
C-20 HVAC Contractor License
The C-20 Warm-Air Heating, Ventilating and Air-Conditioning Contractor license is the main HVAC license in California. Contractors working on heating, ventilation, and air-conditioning systems usually start by researching this classification.
C-38 Refrigeration Contractor License
The C-38 Refrigeration Contractor license applies to refrigeration work, including refrigerated rooms, walk-in coolers, walk-in freezers, refrigerated spaces, temperature insulation, and controls for temperatures below 50°F.
C-4 Boiler, Hot Water Heating and Steam Fitting Contractor License
The C-4 classification is more specialized and applies to boiler, hot-water heating, and steam fitting work. This may be important for contractors working with hydronic heating, steam systems, and boiler equipment.
Full California Class C Specialty Contractor License List
California has 42 separate Class C specialty classifications. These classifications cover the single-trade and specialty areas most contractors recognize in the field.
| License | Classification | License | Classification |
|---|---|---|---|
| C-2 | Insulation and Acoustical | C-32 | Parking and Highway Improvement |
| C-4 | Boiler, Hot Water Heating and Steam Fitting | C-33 | Painting and Decorating |
| C-5 | Framing and Rough Carpentry | C-34 | Pipeline |
| C-6 | Cabinet, Millwork and Finish Carpentry | C-35 | Lathing and Plastering |
| C-7 | Low Voltage Systems | C-36 | Plumbing |
| C-8 | Concrete | C-38 | Refrigeration |
| C-9 | Drywall | C-39 | Roofing |
| C-10 | Electrical | C-42 | Sanitation System |
| C-11 | Elevator | C-43 | Sheet Metal |
| C-12 | Earthwork and Paving | C-45 | Sign |
| C-13 | Fencing | C-46 | Solar |
| C-15 | Flooring and Floor Covering | C-47 | General Manufactured Housing |
| C-16 | Fire Protection | C-49 | Tree and Palm |
| C-17 | Glazing | C-50 | Reinforcing Steel |
| C-20 | Warm-Air Heating, Ventilating and Air-Conditioning | C-51 | Structural Steel |
| C-21 | Building Moving/Demolition | C-53 | Swimming Pool |
| C-22 | Asbestos Abatement | C-54 | Ceramic and Mosaic Tile |
| C-23 | Ornamental Metal | C-55 | Water Conditioning |
| C-27 | Landscaping | C-57 | Well Drilling |
| C-28 | Lock and Security Equipment | C-60 | Welding |
| C-29 | Masonry | C-61 | Limited Specialty |
| C-31 | Construction Zone Traffic Control |
Core CSLB License Requirements
Most California contractor license applicants need to meet several core requirements before CSLB can issue the license.
California Contractor License Exams
Most applicants must pass two exams: the Law & Business exam and the trade exam for the classification they are applying for. For example, a C-36 plumbing applicant typically prepares for the Law & Business exam and the plumbing trade exam. A C-10 electrical applicant prepares for the Law & Business exam and the electrical trade exam.
| License | Common Exam Path |
|---|---|
| B General Building | Law & Business + General Building trade exam |
| B-2 Residential Remodeling | Law & Business + Residential Remodeling trade exam |
| C-36 Plumbing | Law & Business + Plumbing trade exam |
| C-10 Electrical | Law & Business + Electrical trade exam |
| C-20 HVAC | Law & Business + HVAC trade exam |
| C-38 Refrigeration | Law & Business + Refrigeration trade exam |
| C-4 Boiler / Hot Water / Steam Fitting | Law & Business + C-4 trade exam |
Why Practice Exams Help
A contractor license exam is not only about knowing the trade. It is also about understanding the way exam questions are written. Practice exams help you find weak areas, get used to the wording, improve timing, and build confidence before test day.
Practice for the California Contractor ExamCalifornia Contractor License FAQ
What is the main California general contractor license?
The main general contractor classifications are Class A General Engineering, Class B General Building, and B-2 Residential Remodeling.
What license do I need for plumbing in California?
The main California plumbing contractor license is the C-36 Plumbing Contractor license.
What license do I need for electrical work in California?
The main California electrical contractor license is the C-10 Electrical Contractor license. Low-voltage work may fall under the C-7 Low Voltage Systems classification.
What license do I need for HVAC in California?
The main HVAC license is the C-20 Warm-Air Heating, Ventilating and Air-Conditioning Contractor license. Related mechanical work may also involve C-38, C-4, or C-43 depending on the work.
How much experience do I need for a California contractor license?
Most applicants need at least four years of journey-level or higher experience in the classification they are applying for.
Do California contractors need to pass an exam?
Most applicants must pass the Law & Business exam and a trade exam for the license classification they are applying for unless they qualify for an exam waiver.
Is the asbestos open-book exam the same as asbestos certification?
No. The asbestos open-book exam is required before license issuance, but it does not certify a contractor to perform asbestos abatement work.
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