How can I tell if my plumber is licensed in California?
Ask the plumber for their California Contractors State License Board (CSLB) license number, then verify it at the board's public lookup. The license must be Active, the class must include C-36 Plumbing, and there must be no open disciplinary actions. Groundcheck (earthmove.io/trust) does this in under 90 seconds and cross-checks court, OSHA, and BBB records simultaneously.
Confirming a plumber's license in California is a 3-step process. First, get the license number from the contractor — every legitimate plumber working in California should have one and should give it on request. If they refuse or hedge, walk away. Second, plug it into the California Contractors State License Board (CSLB) public lookup at https://www.cslb.ca.gov/. Third, verify three fields on the lookup result: license status (must read "Active"), expiration date (must be in the future), and disciplinary history (must be clean).
What classification matters: C-36 Plumbing. California plumbers working under any other classification are not authorized for the installs, repairs, and maintains water supply, drainage, gas, and sewer systems in residential and commercial buildings you're hiring them for. The threshold rule: Required for any work over $500 in labor and materials. Below that threshold, the plumber may be operating legally without the state license; above it, the license is mandatory.
Red flags that the license isn't legitimate or the plumber is misrepresenting: the license number doesn't return a result, the lookup returns a different name or business than you were given, the status is "Suspended" or "Inactive," the license is in another contractor's name (the plumber is using someone else's license — illegal in every state), or the disciplinary history shows multiple open complaints.
What if the plumber won't share their license number? In California, every licensed plumber is required to display the license number on all advertising, business cards, contracts, and vehicles. If they can't or won't provide it, they're either unlicensed or hiding something.
The fast path: run a free Groundcheck at earthmove.io/trust. Enter the contractor name and California as the state. Groundcheck queries California Contractors State License Board (CSLB), the Secretary of State, federal court records, OSHA inspection history, and BBB complaints, then returns a single sourced verdict. The contractor is never notified.
Detailed California plumber licensing rules: earthmove.io/trust/license/plumber/california.
Verify a California plumber now
Free Groundcheck cross-references California Contractors State License Board (CSLB) licensing with court records, OSHA history, and BBB complaints. Under 90 seconds. The contractor is never notified.