Verify Contractors by Trade Classification

53 CSLB classifications covering 300,681 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.

29,127

contractors

C36

Plumbing

Plumbing contractors for pipes, fixtures, and water systems.

18,080

contractors

C33

Painting & Decorating

Painting and decorating contractors for interior and exterior finishes.

16,400

contractors

C27

Landscaping

Landscaping contractors for outdoor spaces, irrigation, and hardscaping.

12,694

contractors

C20

HVAC

Heating, ventilation, and air conditioning contractors.

12,316

contractors

C15

Flooring

Flooring and floor covering contractors for all floor types.

7,256

contractors

C54

Tile

Tile contractors for ceramic, stone, and mosaic installations.

6,559

contractors

C-8

Concrete

Concrete contractors for foundations, slabs, and structural concrete.

5,752

contractors

C39

Roofing

Roofing contractors for roof installation and repair.

5,678

contractors

C-7

Low Voltage Systems

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

4,977

contractors

C-6

Cabinet & Millwork

Cabinet, millwork, and finish carpentry contractors.

4,541

contractors

C-9

Drywall

Drywall contractors for interior wall and ceiling systems.

3,349

contractors

C17

Glazing

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

3,191

contractors

C53

Swimming Pool

Swimming pool contractors for pool construction and service.

2,981

contractors

C12

Earthwork & Paving

Earthwork and paving contractors for grading and site preparation.

2,544

contractors

C16

Fire Protection

Fire protection contractors for sprinklers and fire suppression systems.

2,281

contractors

C29

Masonry

Masonry contractors for brick, block, and stone work.

2,184

contractors

C35

Lathing & Plastering

Lathing and plastering contractors for interior finishes.

1,899

contractors

C21

Building Moving & Demolition

Building moving and demolition contractors.

1,880

contractors

C13

Fencing

Fencing contractors for all types of fence installation.

1,874

contractors

C38

Refrigeration

Refrigeration contractors for commercial cooling systems.

1,715

contractors

C51

Structural Steel

Structural steel contractors for steel frame construction.

1,596

contractors

C43

Sheet Metal

Sheet metal contractors for ductwork and metal fabrication.

1,346

contractors

C46

Solar

Solar contractors for photovoltaic and solar thermal systems.

1,248

contractors

C-2

Insulation & Acoustical

Insulation and acoustical contractors for thermal and sound insulation.

1,216

contractors

C60

Welding

Welding contractors for metal joining and fabrication.

1,135

contractors

C23

Ornamental Metal

Ornamental metal contractors for decorative metalwork.

1,113

contractors

C-5

Framing & Rough Carpentry

Framing and rough carpentry contractors for structural wood framing.

1,084

contractors

C42

Sanitation System

Sanitation system contractors for septic and sewage systems.

992

contractors

C45

Sign

Sign contractors for commercial and roadway signage.

898

contractors

C57

Well Drilling

Well drilling contractors for water wells.

758

contractors

C-4

Boiler, Hot Water & Steam

Boiler, hot water heating, and steam fitting contractors.

710

contractors

C34

Pipeline

Pipeline contractors for water, gas, and sewer lines.

555

contractors

C32

Parking & Highway Improvement

Parking and highway improvement contractors.

528

contractors

C31

Traffic Control

Construction zone traffic control contractors.

462

contractors

C47

Manufactured Housing

General manufactured housing contractors.

461

contractors

C28

Lock & Security Equipment

Lock and security equipment contractors.

379

contractors

C22

Asbestos Abatement

Asbestos abatement contractors for hazardous material removal.

318

contractors

C55

Water Conditioning

Water conditioning contractors for water treatment systems.

313

contractors

C50

Reinforcing Steel

Reinforcing steel contractors for rebar installation.

270

contractors

C11

Elevator

Elevator contractors for installation and service of elevators and escalators.

224

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.