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Homeowner guide

How to Verify a California Plumbing Contractor License (CSLB)

In California, plumbing work of $500 or more (labor and materials) must be performed by a contractor licensed by the Contractors State License Board (CSLB). Plumbing falls under the C-36 classification. Verifying a license takes two minutes and is the single most useful check you can do before hiring anyone — including anyone we connect you with.

Step by step

1. Go to the CSLB license check at cslb.ca.gov.
2. Search by license number (recommended), business name, or personnel name.
3. Confirm the license status is Active, the classification includes C-36 Plumbing, and the business name matches who you're dealing with.
4. Check the bond and workers' compensation lines — a contractor with employees must carry workers' comp.

Red flags

• A license number that doesn't match the business name on the estimate.
• “Borrowed” license numbers — the qualifier should be connected to the company.
• Cash-only deals or pressure to skip a written contract.
• For jobs of $500+, no license at all.

CSLB also explains contract requirements and down payment limits on its consumer pages. If a dispute arises, CSLB accepts complaints against licensed and unlicensed operators alike.

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