Skip to content
State files updated Nov 1, 2026
Look up a contractor
MenuClose

Home / License lookup / California / Gaehwiler M Construction Inc

California contractor license

Gaehwiler M Construction Inc

Gaehwiler M Construction Inc of San Francisco holds California license 510649 (B General Building, C4 Boiler, Hot Water Heating and Steam Fitting, C36 Plumbing). The CSLB file dated Nov 1, 2026 lists it as active.1 It expires May 31, 2027.

Licensed 39 years, longer than 94% of 249 active San Francisco plumbing contractors.

Active

Gaehwiler M Construction Inc, San Francisco

License
510649
Class
B General Building; C4 Boiler, Hot Water Heating and Steam Fitting; C36 Plumbing
Expires
May 31, 2027
Bond
$25,000
Workers' comp
Insured to Oct 1, 2027

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 Mar 15, 2023, continuous
Liability insurance
Not in the CSLB fileCheck with the board
Workers' comp
InsuredTravelers Property Casualty Company Of America, from Oct 1, 2026, to Oct 1, 2027

Who is on this license?

Officer
Martin A. GaehwilerSince May 13, 1987

What work does this license cover?

Issued May 13, 1987.

Which other San Francisco businesses hold B General Building?

Plumbing Contractors in San FranciscoCalifornia plumbing contractorsCalifornia HVAC 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)