How to check a contractor's licence in California
In California, contractors are licensed by the Contractors State License Board (CSLB). You can check a licence on the CSLB website or by phone at (800) 321-CSLB (2752). Local Business America does not check licences, verify businesses or rank them. Always check with the CSLB yourself.
Researched October 2026, from the official sources named on this page. Rules change, so confirm with the board before you rely on them.
The steps
- 1
Ask for the licence number
Ask the contractor for their licence number and the name on the licence. CSLB says contractors must put their licence number on their business card and on all bids and contracts. Look for it on those papers.
- 2
Open the CSLB lookup
Go to the CSLB page called Check a Contractor License or Home Improvement Salesperson (HIS) Registration: https://www.cslb.ca.gov/OnlineServices/CheckLicenseII/CheckLicense.aspx. You can also call (800) 321-CSLB (2752).
- 3
Search the licence
Type in the licence number. If you do not have it, search by the business name or by the name of the person. Each way is listed on the CSLB page.
- 4
Read the result
Check the status of the licence. The CSLB page says the lookup covers complaint disclosure. Make sure the name matches the person or company you are dealing with.
- 5
Match the licence class to the job
Each licence has a class. Check that the class fits your project, for example C-10 for electrical work or C-39 for roofing. See the list below.
Where to look
The state runs a free tool to check a contractor's licence. It is on the CSLB website. The page is called Check a Contractor License or Home Improvement Salesperson (HIS) Registration.
You can search by licence number, by the contractor's business name, or by the name of a person. There are also searches for salespeople who sell home improvement work.
CSLB says the tool is offline from Sunday at 8 p.m. to Monday at 6 a.m. for maintenance. If it does not load, try again later.
What the licence classes cover
A class is a type of work. A B licence is for a general building contractor, whose work involves at least two unrelated building trades. A C-10 licence is for electrical work. A C-20 licence is for warm-air heating, ventilating and air-conditioning. A C-36 licence is for plumbing.
A C-39 licence is for roofing. A C-53 licence is for building swimming pools, spas and hot tubs. A contractor should hold the class that matches your job.
CSLB lists every class on its Licensing Classifications pages. If you are not sure which class fits, call CSLB and ask.
Other things to ask about
CSLB says a contractor with employees must carry workers' compensation insurance. Ask the contractor to show you proof of it.
CSLB also advises you to get at least three written bids. It warns that an unlicensed operator may give you a low bid, but that the risks outweigh any benefit.
California requires a written contract for home improvement work above a set amount. CSLB also limits how big a down payment can be. Read the CSLB contract page before you sign.
What this site does and does not do
Local Business America does not check licences, verify businesses or rank them. We are not a licensing body.
Use our directory to find names. Then check each licence yourself with the CSLB before you hire.
Common questions
- Who licenses contractors in California?
- The Contractors State License Board, called CSLB. It is part of the state government.
- How do I check a contractor's licence?
- Use the CSLB online lookup, or call (800) 321-CSLB (2752). You can search by licence number, business name or personnel name.
- What licence does a plumber need?
- A C-36 Plumbing licence. CSLB describes it as covering a safe water supply and the proper disposal of waste from a building.
- What licence does an electrician or a roofer need?
- An electrician needs a C-10 Electrical licence. A roofer needs a C-39 Roofing licence.
- Which licence covers air conditioning and pools?
- Air conditioning and heating is C-20. Swimming pools, spas and hot tubs are C-53.
- Should the contractor's licence number be on the paperwork?
- Yes. CSLB says contractors must put their licence number on their business card and on all bids and contracts.
- What licence do I need to know about for a big remodel with many trades?
- A B General Building licence covers work that uses at least two unrelated trades. CSLB's classification pages explain what it can and cannot do. Check with CSLB if you are unsure.