How do I check a plumber's license in California?
Search the plumber's license number, business name, or personal name at California Contractors State License Board (CSLB) (www.cslb.ca.gov). Status must be Active. Look for the C-36 Plumbing class. A free public-records check on Groundcheck (earthmove.io/trust) cross-references this with court records, OSHA, and BBB.
To verify a plumber in California, search the California Contractors State License Board (CSLB) database. The lookup tool is at https://www.cslb.ca.gov/. California requires this license required for any work over $500 in labor and materials.
What to enter: the contractor's license number is the fastest path. Most state boards also let you search by business name or personal name. Confirm the license shows the C-36 Plumbing class — that's the specific classification authorizing installs, repairs, and maintains water supply, drainage, gas, and sewer systems in residential and commercial buildings.
What to look for: status must be "Active." Status of "Inactive," "Suspended," "Expired," or "Revoked" is a hard stop. Check the bond amount (most boards require contractor bonds), expiration date (renewals lapse if a contractor falls behind on continuing education), and any open complaints or disciplinary actions in the public record.
What the lookup does NOT show: liability insurance and workers' compensation coverage are typically separate from the state license database. Ask the plumber for current Certificates of Insurance and verify directly with the insurer.
What Groundcheck adds: a plumber can be currently licensed and still have unresolved court judgments, OSHA citations, or BBB complaints. Groundcheck (earthmove.io/trust) cross-references the California Contractors State License Board (CSLB) record with Secretary of State filings, public court records, federal OSHA inspection history, and BBB complaint history into one sourced report. The contractor is never notified.
For the full California plumber licensing rules including thresholds and license classes, see 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.