How to Verify a Contractor License in California: 5-Minute Method

Why Altadena Homeowners Can't Skip This Check

For one Eaton Fire survivor, the lesson cost $18,000. An unlicensed contractor took the money, abandoned the rebuild, and disappeared — a story that has become painfully common across the LA County recovery zones. According to the National Insurance Crime Bureau, contractor fraud reports rose roughly 40% between 2023 and 2025, and disaster survivors are the primary targets.

Enforcement is catching up, but slowly. The LA County District Attorney's office and the Contractors State License Board have run joint sting operations in the wildfire zones, charging six unlicensed contractors in the Palisades Fire area alone, with illegal bids totaling about $1.2 million. Contracting without a license in a disaster zone is now a felony carrying up to three years in prison.

DA Nathan J. Hochman put the homeowner-side risk plainly: "Hiring an unlicensed contractor is never a good deal, leaving you at risk of illegal down payments, fraud, unsafe construction and an inability to sell your home down the line." For Altadena homeowners planning an ADU or a rebuild, the stakes could not be higher.

The ADU market has its own fraud history. In one widely reported case, victims lost as much as $168,000 to a single ADU builder, and CSLB investigators say hundreds of victims exist across the industry, according to KCRA reporting. A license number on a truck or a website means nothing until you confirm it on the state's own database.

Why does this matter so much for Altadena specifically? Because the conditions that attract fraudsters are all present at once:

• More than 16,000 homes and structures were destroyed in the LA County wildfires, creating overwhelming contractor demand.
• Survivors are emotionally exhausted and financially pressured — exactly the state fraudsters look for.
• Insurance payouts mean cash is available up front, tempting homeowners into oversized deposits.
• Recovery-zone enforcement, while active, cannot screen every bid before you sign.

The good news: verification takes five minutes and costs nothing. CSLB Registrar David Fogt has said protecting wildfire survivors from unlicensed contractors is the board's priority, and the state gives you the tool to do it yourself at cslb.ca.gov — no expertise required. Think of it as the cheapest insurance your ADU or rebuild project can buy.

At Altadena ADU Builder, we treat the license check as step one of any builder conversation. For example, JMB Builders LLC (CSLB #1103479), an Altadena-based general contractor doing Eaton Fire rebuilds and ADUs, carries a license number you can verify yourself on the CSLB site in under a minute. Any builder worth hiring should pass the same test — and if one resists the check, that itself is your answer.

The 5-Minute CSLB Method: License, Bond, Insurance

Verifying a contractor in California takes less time than scrolling their Instagram portfolio — and the state gives you the exact tool to do it. The Contractors State License Board's "Check a License or HIS Registration" tool at cslb.ca.gov, or the verification line at 800-321-2752, returns a full license record in seconds, according to CSLB guidance for homeowners.

Remember the threshold: any project with combined labor and materials of $500 or more legally requires a CSLB license. A backyard ADU — typically a six-figure project — is nowhere near that line. And in Eaton Fire recovery zones, the stakes are criminal: unlicensed contracting during a declared disaster is a felony carrying up to three years in prison and a $10,000 fine, and LA County prosecutors are actively charging unlicensed contractors in wildfire zones.

Part 1: Status and classification. Search by license number or business name. The license must show "active" status, and the classification matters more than most homeowners realize. For an ADU, you want Class B General Building — the classification CSLB's own ADU guidance identifies as correct, per licensing analyses of the CSLB ADU fact sheet. Two nuances trip up ADU clients:

• B-2 Residential Remodeling licenses (created 2021) cannot contract for structural work on footings, foundations, load-bearing walls, or roof structures — disqualifying them for most ground-up ADUs.
• C-47 covers manufactured-home ADUs only, not site-built construction.
• The business name on your contract must match the license record exactly — a marketing brand or different LLC is a red flag.

Part 2: The bond. State law requires a $25,000 contractor bond (B&P §7071.6). The license record shows whether the bond is current. If a licensed contractor damages your project and disappears, that bond is your recovery mechanism — one reason the Anchored Tiny Homes ADU collapse left victims like one homeowner out $168,000, with CSLB saying hundreds of ADU clients were affected.

Part 3: Workers' compensation. The record shows whether workers' comp is on file or the contractor holds an exemption. An exemption means the contractor certifies it has no employees — fine for a solo operator, but a crew showing up on your property with an exempt license is a problem. Note that roofing, concrete, HVAC, and asbestos-abatement classifications cannot use the exemption at all.

At Altadena ADU Builder, we encourage every homeowner to run this exact check on any builder they meet — including the licensed general contractors we feature, such as JMB Builders LLC (CSLB #1103479). A builder who welcomes verification is a builder worth talking to.

ADU-Specific Red Flags Most Homeowners Miss

An active license number isn't enough — the classification on that license determines whether your builder can legally construct an ADU at all. According to CSLB's ADU guidance, a backyard ADU requires a Class B General Building license. Two other classifications trip up homeowners constantly.

The B-2 Residential Remodeling classification, created in 2021, cannot contract for structural changes to load-bearing portions — footings, foundations, load-bearing walls, or roof structures. An ADU is a new structure, so a B-2 holder pitching your garage conversion with a second-story addition is bidding outside their license. The C-47 classification applies only to manufactured homes, not site-built ADUs.

Beyond classification, watch for these red flags before signing anything:

• No license number in advertisements. CSLB investigators specifically flag contractors whose online ads omit a license number — it's often the first sign of unlicensed activity.
• Contract name doesn't match the license record. If the contract says one LLC but the CSLB record shows another, you may have no bond or insurance protection on the entity actually taking your money.
• Down payments exceeding $1,000 or 10% of the contract, whichever is less. Anything larger is illegal under California law.
• Permits not pulled under the builder's own license. In Altadena, you can confirm this yourself through the LADBS Permit & Inspection Report search — a licensed contractor pulls permits under their own number, not yours.

The stakes are real. Contractor fraud reports rose roughly 40% between 2023 and 2025 per the National Insurance Crime Bureau, and one Eaton Fire survivor lost $18,000 to an unlicensed contractor who abandoned the project. In the Palisades recovery zone, the LA County DA charged six unlicensed contractors with illegal bids totaling about $1.2 million.

A valid-looking license can also hide a "rented qualifier" — someone else's license operated by an unqualified party. CSLB has formed a dedicated task force to investigate these arrangements, and legal analysts note that the days of paper qualifiers are coming to an end. Matching the contract name, classification, and permit record to the CSLB listing catches most of these schemes.

When we at Altadena ADU Builder vet builders for our local guide, we run this same check — including on our featured builder, JMB Builders LLC (CSLB #1103479), whose number we publish precisely so you can verify it yourself at cslb.ca.gov. Want help applying this to your own property? Book a free ADU feasibility consultation and get a cost-quiz concept render for your Altadena lot.

Run the Check on Your Own Builder — Here's Ours

Now that you know the three-part check — license, bond, insurance — run it on any Altadena builder you're considering. Go to the CSLB's "Check a License or HIS Registration" tool at cslb.ca.gov, or call 800-321-2752, and search by license number or business name. Confirm the license is active, the classification is Class B General Building (the correct classification for ADUs; a B-2 Residential Remodeling license cannot touch load-bearing structure), the $25,000 contractor bond is current, and workers' compensation is on file.

This matters more in Altadena right now than almost anywhere in California. Contractor fraud reports rose nearly 40% between 2023 and 2025, and one Eaton Fire survivor lost $18,000 to an unlicensed contractor who abandoned the project. LA County and CSLB enforcement operations are actively charging unlicensed contractors in wildfire recovery zones, and contracting without a license in a disaster zone is now a felony carrying up to three years in prison.

While you're on the CSLB page, scan the record for red flags:

• The business name on the contract doesn't match the license record exactly — marketing brands or different LLCs are a warning sign
• A disciplinary or complaint history on the license
• An "exemption" filed for workers' compensation when the builder will clearly have employees on your ADU site
• No license number displayed anywhere in the contractor's ads or website

To show you how fast this is, here's a worked example. JMB Builders LLC is an Altadena-based licensed general contractor, CSLB #1103479, building custom homes, ADUs, and whole-home remodels in the area, including Eaton Fire rebuilds. Type that license number into the CSLB lookup yourself and confirm what you'd want to see: an active Class B license, a current $25,000 bond, and workers' compensation on file. We feature JMB Builders as a paid placement on this guide, but the point isn't to take our word for it — the entire value of this method is that every claim a builder makes is independently verifiable in about five minutes, for JMB or anyone else.

Once your check comes back clean, the next step is understanding what your property can actually support. At Altadena ADU Builder, we offer a free ADU feasibility consultation for Altadena homeowners — and if you take our cost quiz first, you'll receive a concept render showing what an ADU could look like on your lot. Bring the render and your verified builder shortlist to the consultation, and you'll be starting from facts, not sales pitches.

Verify the license. Check the bond and insurance. Then plan the build.