Verify Contractors by Trade Classification

53 CSLB classifications covering 304,920 contractors, each checked against 6 data sources

About CSLB Classifications

The California Contractors State License Board (CSLB) issues licenses in three main categories: A (General Engineering), B (General Building), and C (Specialty). Each classification authorizes specific types of construction work. Contractors may hold multiple classifications.

C - Specialty Licenses

C10

Electrical

Electrical contractors for wiring, lighting, and electrical systems.

29,525

contractors

C36

Plumbing

Plumbing contractors for pipes, fixtures, and water systems.

18,350

contractors

C33

Painting & Decorating

Painting and decorating contractors for interior and exterior finishes.

16,648

contractors

C27

Landscaping

Landscaping contractors for outdoor spaces, irrigation, and hardscaping.

12,873

contractors

C20

HVAC

Heating, ventilation, and air conditioning contractors.

12,505

contractors

C15

Flooring

Flooring and floor covering contractors for all floor types.

7,348

contractors

C54

Tile

Tile contractors for ceramic, stone, and mosaic installations.

6,634

contractors

C-8

Concrete

Concrete contractors for foundations, slabs, and structural concrete.

5,849

contractors

C39

Roofing

Roofing contractors for roof installation and repair.

5,804

contractors

C-7

Low Voltage Systems

Low voltage systems contractors for alarms, audio/video, and communications.

5,046

contractors

C-6

Cabinet & Millwork

Cabinet, millwork, and finish carpentry contractors.

4,586

contractors

C-9

Drywall

Drywall contractors for interior wall and ceiling systems.

3,398

contractors

C17

Glazing

Glazing contractors for windows, glass doors, and glass installations.

3,235

contractors

C53

Swimming Pool

Swimming pool contractors for pool construction and service.

3,022

contractors

C12

Earthwork & Paving

Earthwork and paving contractors for grading and site preparation.

2,571

contractors

C16

Fire Protection

Fire protection contractors for sprinklers and fire suppression systems.

2,301

contractors

C29

Masonry

Masonry contractors for brick, block, and stone work.

2,208

contractors

C35

Lathing & Plastering

Lathing and plastering contractors for interior finishes.

1,921

contractors

C21

Building Moving & Demolition

Building moving and demolition contractors.

1,910

contractors

C13

Fencing

Fencing contractors for all types of fence installation.

1,899

contractors

C38

Refrigeration

Refrigeration contractors for commercial cooling systems.

1,734

contractors

C51

Structural Steel

Structural steel contractors for steel frame construction.

1,619

contractors

C43

Sheet Metal

Sheet metal contractors for ductwork and metal fabrication.

1,369

contractors

C46

Solar

Solar contractors for photovoltaic and solar thermal systems.

1,261

contractors

C-2

Insulation & Acoustical

Insulation and acoustical contractors for thermal and sound insulation.

1,227

contractors

C60

Welding

Welding contractors for metal joining and fabrication.

1,155

contractors

C23

Ornamental Metal

Ornamental metal contractors for decorative metalwork.

1,128

contractors

C-5

Framing & Rough Carpentry

Framing and rough carpentry contractors for structural wood framing.

1,105

contractors

C42

Sanitation System

Sanitation system contractors for septic and sewage systems.

1,000

contractors

C45

Sign

Sign contractors for commercial and roadway signage.

906

contractors

C57

Well Drilling

Well drilling contractors for water wells.

759

contractors

C-4

Boiler, Hot Water & Steam

Boiler, hot water heating, and steam fitting contractors.

714

contractors

C34

Pipeline

Pipeline contractors for water, gas, and sewer lines.

559

contractors

C32

Parking & Highway Improvement

Parking and highway improvement contractors.

536

contractors

C31

Traffic Control

Construction zone traffic control contractors.

470

contractors

C47

Manufactured Housing

General manufactured housing contractors.

466

contractors

C28

Lock & Security Equipment

Lock and security equipment contractors.

380

contractors

C22

Asbestos Abatement

Asbestos abatement contractors for hazardous material removal.

320

contractors

C55

Water Conditioning

Water conditioning contractors for water treatment systems.

316

contractors

C50

Reinforcing Steel

Reinforcing steel contractors for rebar installation.

273

contractors

C11

Elevator

Elevator contractors for installation and service of elevators and escalators.

228

contractors

Why Trade Classification Matters for Verification

California law requires contractors to hold the correct CSLB classification for any project valued at $500+ (labor and materials). Hiring a contractor with the wrong classification is the same as hiring an unlicensed contractor under California law.

CSLB Classification Categories

  • Class A - General Engineering: Infrastructure (highways, bridges, utilities)
  • Class B - General Building: Building construction and structures
  • Class C - Specialty: Trade-specific (electrical, plumbing, HVAC, roofing)
  • Class D - Specialty: Limited-scope specialty work

SiteVetter goes beyond CSLB license status. Each trade page shows how many contractors in that classification have records in SAM.gov, OSHA, DOL, and EPA databases—federal violations a standard license check misses.

Need contractors in a specific area? Verify by city to check contractors near you.

Data sourced from California Contractors State License Board. Updated weekly.