How to Check a Contractor's License

Five minutes on a state website filters out the worst outcomes in residential construction. Here's the walkthrough.

Where: the Contractors State License Board (CSLB) license lookup at cslb.ca.gov. Search by license number (any legitimate contractor volunteers it — it's legally required on their ads and contracts) or by business name.

What to read, field by field:

• Status: must say "Active." Suspended, expired, or revoked ends the conversation. Also confirm the business name on the license matches the name on your contract — a license borrowed from a cousin's company is a classic scheme.
• Classification: "B" (General Building) is the standard for ADU construction. A "B" may take the whole project and subcontract trades. (Specialty licenses — C-10 electrical, C-36 plumbing — are for single-trade jobs, not your GC role.)
• Bond: present and current. California requires contractors to carry a license bond. It's small relative to your project, but its absence means non-compliance.
• Workers' compensation: the big one homeowners skip. If the lookup shows a workers' comp exemption (claiming no employees) and the contractor shows up with a crew — that's both illegal and your liability exposure when someone's injured on your property. Crew-based work requires coverage. Verify it; then ask for the insurance certificate directly too (liability + workers' comp), issued from the insurer.
• Disclosure items: past suspensions, bond claims, or disciplinary actions appear here. One old resolved item with a good explanation may be forgivable; patterns aren't.

Two supplementary checks worth the extra ten minutes: civil case search on your county court's website (serial litigants reveal themselves), and the license's issue date against the contractor's claimed experience ("twenty years in business" with a license issued three years ago is a resume, not a record).

And the golden rule this lesson serves: unlicensed contracting for work over $1,000 is illegal in California, uninsurable, and unprotectable — no bond, no CSLB recourse, no valid warranty. The discount is never worth it, and the person offering it has told you who they are.