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State files updated Oct 31, 2026
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California contractor license

Dittmann Plumbing Inc

Dittmann Plumbing Inc of San Mateo holds California license 311169 (C36 Plumbing). The CSLB file dated Oct 31, 2026 lists it as active.1 It expires Sep 30, 2028.

Licensed 51 years, longer than 84% of 25 active San Mateo plumbing contractors.

Active

  • Workers' comp ends Nov 16, 2026 (16 days)

Dittmann Plumbing Inc, San Mateo

License
311169
Class
C36 Plumbing
Expires
Sep 30, 2028
Bond
$25,000
Workers' comp
Insured to Nov 16, 2026

CSLB file dated Oct 31, 2026

From the CSLB file dated Oct 31, 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 Oct 31, 2026. Confirm with the board: CSLB license check

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

Bond
$25,000Atlantic Specialty Insurance Company, from Apr 11, 2026, continuous
Liability insurance
Not in the CSLB fileCheck with the board
Workers' comp
InsuredEmployers Preferred Insurance Company, from Nov 16, 2025, to Nov 16, 2026

Who is on this license?

Responsible managing officer, CEO and president
Donald S. TaylorSince Jun 23, 2011

What work does this license cover?

Issued Oct 14, 1975.

Which other San Mateo businesses hold C36 Plumbing?

California plumbing contractors

What should you check before hiring?

What to ask before you hire

  1. Ask whether it has been renewed. Something on this license ends within 60 days. Check again before you pay a deposit.
  2. Get the license number in writing. The name on the license should match the name on your contract and invoice.
  3. Check the class covers the job. A license for one trade doesn't cover another. California license classes
  4. Ask for a certificate of insurance sent to you by the insurance agent, not handed over by the contractor. How to read a COI
  5. 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.
  6. 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, Oct 31, 2026)
  2. Contractors State License Board (CSLB)