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California contractor license

Mason Plumbing Inc

Mason Plumbing Inc of San Anselmo holds California license 817803 (C36 Plumbing). The CSLB file dated Nov 1, 2026 lists it as active.1 It expires Apr 30, 2027.

Licensed 23 years, longer than 76% of 9,564 active California plumbing contractors.

Active

Mason Plumbing Inc, San Anselmo

  • Workers' comp on file ended Oct 28, 2026.
License
817803
Class
C36 Plumbing
Expires
Apr 30, 2027
Bond
$25,000
Workers' comp
Insured to Oct 28, 2026

CSLB file dated Nov 1, 2026

From the CSLB file dated Nov 1, 2026. Not a consumer report; check the board before you hire.

Has the board taken action on this license?

None in the CSLB file dated Nov 1, 2026. Confirm with the board: CSLB license check

What bond, insurance and workers' comp are on file?

Bond
$25,000American Contractors Indemnity Company, from Jan 9, 2024, continuous
Liability insurance
Not in the CSLB fileCheck with the board
Workers' comp
InsuredTechnology Insurance Company Inc, from Oct 28, 2025, to Oct 28, 2026

Who is on this license?

Officer
Kamber A. MasonSince Apr 16, 2007
Responsible managing officer, CEO and president
Cameron P. MasonSince Mar 5, 2003

What work does this license cover?

Issued Mar 5, 2003. Reissued Apr 16, 2007.

Which other San Anselmo businesses hold C36 Plumbing?

California plumbing contractors

What should you check before hiring?

What to ask before you hire

  1. Get the license number in writing. The name on the license should match the name on your contract and invoice.
  2. Check the class covers the job. A license for one trade doesn't cover another. California license classes
  3. Ask for a certificate of insurance sent to you by the insurance agent, not handed over by the contractor. How to read a COI
  4. Ask who will be on site. If a crew works on your property, ask for proof of workers' comp. An exemption on file means the contractor told the CSLB it has no employees.
  5. Put it in a written contract: license number, price, start date and payment schedule. Check the license again on the day you sign.

If the license is lapsed

  1. Don't sign or pay a deposit until the CSLB shows the license active again.
  2. Ask the contractor why. For a bond or insurance lapse, ask for proof that the new bond or policy was filed with the CSLB, then check again.
  3. If work has started, hold further payments, keep the contract, receipts and photos, and file a complaint with Contractors State License Board (CSLB).
  4. Check another contractor. California license lookup

Sources

  1. CSLB License Master (cslb.ca.gov, Nov 1, 2026)
  2. Contractors State License Board (CSLB)