Unlicensed ADU builders and outright scam artists cost California, Texas, and Arizona homeowners tens of thousands of dollars every year — usually before a single permit gets pulled. Here's how to verify a contractor's credentials, structure payments safely, and spot the red flags before you sign anything in 2026.
- ADU builder scams usually start with a deposit over 10% of the contract — California caps deposits at $1,000 or 10%, whichever is less.
- Verify license, bond, and insurance directly with the state board before signing; a texted license number proves nothing.
- Texas has no statewide general contractor license, so insurance certificates and permit history matter more than a license number there.
- Build With A Plan's vetted builder matching skips this vetting step entirely — every matched contractor is pre-checked before you ever meet them.
- Tie every payment to a completed inspection milestone, never a calendar date, to avoid losing money on unfinished ADU work.
Why this matters
ADU construction runs $150,000 to $300,000+ depending on square footage and finish level, and most of that money changes hands in a handful of large payments. That's exactly the setup a scam contractor wants: a homeowner excited about rental income, a permit process they don't understand, and a payment schedule they haven't scrutinized.
The damage isn't limited to lost deposits. An unlicensed contractor who pulls no permit — or worse, pulls one under your name instead of theirs — leaves you personally liable if an inspector red-tags the work or a worker gets hurt on your property. Learning how to vet an ADU builder before signing a contract is the single highest-leverage thing you can do before construction starts.
This matters more in 2026 than it did five years ago. ADU permit volume has climbed sharply across California, Texas, and Arizona since state-level ADU laws loosened zoning restrictions, and scam operators have followed the money — advertising heavily on Facebook Marketplace and Nextdoor with stock photos and no verifiable job history.
What you'll need
- The contractor's full legal business name and license number (not just a first name and a phone number)
- 30-45 minutes to run license, bond, and insurance checks on your state's licensing board website
- Your city or county permit portal login, or the phone number for the building department
- At least two additional bids to compare scope and pricing
- A written contract template with milestone-based payment terms
The steps
1. Verify the license number before the first phone call ends
Every legitimate ADU contractor in California carries a Contractors State License Board (CSLB) number you can look up in seconds on the CSLB public database. Arizona contractors carry a Registrar of Contractors (ROC) number with the same kind of public lookup. Texas is the exception — the state issues no general statewide contractor license, so a Texas ADU builder's legitimacy rests on local business registration, insurance, and permit history instead of a license number.
If a contractor gives you a license number that doesn't match their business name, or refuses to give one at all, stop the conversation. This single check filters out the majority of ADU builder scams before you've spent a dollar.
Common mistake: accepting a screenshot of a license certificate instead of looking the number up yourself on the state site.
2. Pull the license's disciplinary and complaint history
CSLB and ROC lookups show more than active status — they show suspended licenses, unresolved complaints, and disciplinary actions. A license that's active but carries three open complaints from the last 12 months is a real warning sign, not a technicality.
Cross-check the business name against your state's Secretary of State business registry too. A contractor operating under a brand-new LLC formed two months ago, with no prior business history, deserves extra scrutiny even if the license itself checks out.
3. Confirm bonding and insurance directly with the carrier
California requires licensed contractors to carry a $25,000 contractor's bond. Arizona sets its own bond minimums tied to the size of the contractor's business. Ask for the certificate of insurance (COI) and call the insurance carrier listed on it to confirm the policy is active — don't accept a PDF alone, since COIs get forged or allowed to lapse.
General liability coverage protects you if the contractor damages your property. Workers' compensation protects you if a worker is injured on your job site and tries to come after your homeowner's policy instead.
Common mistake: confirming insurance exists but never checking the coverage dates — a policy that expired last month is functionally no policy at all.
4. Check who's actually pulling the permit
The permit application should list the licensed contractor as the permit holder, not you as the homeowner, unless you're deliberately owner-building. If a contractor asks you to pull the permit yourself "to save time," that's a direct signal they want to avoid licensing accountability for the work.
Call your city or county building department and ask whether that contractor's license number has pulled any permits in the last 12 months. Zero activity from a contractor claiming years of ADU experience is a red flag worth asking about directly.
5. Cap the deposit before you negotiate anything else
California law limits the initial deposit a home improvement contractor can collect to 10% of the contract price or $1,000, whichever is less, under CSLB Business & Professions Code 7159. Any California contractor asking for 20%, 30%, or "half up front" is already outside the law.
Outside California, treat any upfront request above 10-15% of total project cost as a negotiating point, not a given. Legitimate ADU builders get paid through a payment schedule, not a lump sum before ground breaks.
6. Structure the payment schedule around inspections, not the calendar
Tie each draw to a completed, inspected phase of construction — foundation poured and inspected, framing complete and inspected, rough plumbing and electrical signed off, final inspection passed. This is exactly how construction draws work on financed ADU builds, and it's worth understanding how a HELOC works for ADU construction even if you're paying cash, because the milestone logic is identical.
A calendar-based schedule ($10,000 every two weeks regardless of progress) lets a contractor collect money without matching progress. Milestone-based schedules protect you from paying for work that never happened.
Common mistake: agreeing to a payment schedule with more than 5-6 draws that are vague ("progress payment 1," "progress payment 2") instead of tied to named, inspectable milestones.
7. Get three bids and compare scope line by line, not just the bottom number
The lowest bid on an ADU project is frequently the one missing scope — no landscaping restoration, no utility hookup fees, cheaper-grade windows, or an allowance for finishes that's unrealistically low. Line up three bids side by side and confirm each one covers the same square footage, the same finish level, and the same permit and design costs before comparing totals.
A bid that's 30-40% below the other two, on paper covering identical scope, usually means the contractor plans to cut corners, change-order you mid-project, or both.
Troubleshooting
Contractor won't provide a license number over the phone. Treat this as an automatic disqualifier — legitimate contractors give this information freely because it's public record anyway.
Contractor pressures you to sign the same day for a "discount." Real ADU pricing doesn't expire in 24 hours. This is a classic high-pressure sales tactic used to prevent you from checking references or licenses.
Permit pulled under your name instead of the contractor's. Stop work and contact your building department directly. This shifts liability onto you and often signals the contractor isn't licensed to pull permits in your jurisdiction.
No physical business address, only a personal cell and a Facebook page. Search the business name in your Secretary of State registry. No registered entity plus no address is a strong scam indicator.
Contractor asks for payment via Venmo, Zelle, or cash only. Legitimate contractors invoice through their business and accept checks or ACH tied to a business bank account. Payment apps to a personal account leave you with no paper trail if something goes wrong.
Bid seems too good compared to two others for identical scope. Ask the contractor to itemize materials, labor, and permit fees separately. Vague, one-line bids hide the corners about to get cut.
Skip the vetting and get matched
Build With A Plan pre-vets every builder before you ever meet one.
Tools and resources
- Your state's contractor licensing board website (CSLB in California, ROC in Arizona) for license, bond, and complaint lookups
- Your county Secretary of State business registry to confirm the contractor's legal entity
- Your city or county building department permit portal to check permit history under a contractor's license
- How to vet an ADU builder before signing a contract for a full contract-review checklist
- How to convert your garage into an ADU for rental income if your project is a conversion rather than new construction, since scope verification differs
What to do next
Once a contractor clears license, bond, insurance, and permit-history checks, the next risk is financing structure — paying out of pocket versus draws tied to a loan. If you're financing the build, understand ADU financing options for first-time landlords before you sign a construction contract, since your lender's draw schedule needs to match the milestone-based payment plan you negotiate with the builder.
FAQ
What are the most common ADU builder scams?
The most common ADU builder scams involve collecting a large deposit (often 30-50% of the contract) before any permit is pulled, then delaying, disappearing, or demanding more money mid-project. Unlicensed operators also sometimes pull permits under the homeowner's name to avoid licensing accountability.
How do I check if an ADU contractor is licensed?
Look up the contractor's license number on your state's public licensing board site — CSLB in California, ROC in Arizona. Texas has no statewide general contractor license, so verify local business registration and insurance instead.
Is it normal for a contractor to ask for a large deposit?
No. California law caps deposits at 10% of the contract or $1,000, whichever is less, under CSLB rules. Any contractor asking for 20% or more up front is outside standard practice and worth walking away from.
How much should I pay upfront for an ADU builder?
Cap upfront payment at 10% of total project cost or less, then structure remaining payments as draws tied to inspected construction milestones like foundation, framing, and rough-in completion.
Can I sue an unlicensed ADU contractor?
You can pursue civil action, but recovery is harder without a license, bond, or insurance backing the contractor. This is why verifying license status before signing matters more than pursuing recourse after the fact.
Does Texas require a license for ADU builders?
Texas does not issue a statewide general contractor license, unlike California or Arizona. Verify a Texas ADU builder through local business registration, insurance certificates, and permit history instead of a state license number.
How do I verify a contractor's insurance is real?
Request the certificate of insurance and call the insurance carrier directly to confirm the policy is active and matches the coverage dates listed. A PDF alone can be outdated or forged.
One last thing
The fastest scam-prevention step most homeowners skip isn't a license lookup — it's calling the building department and asking how many permits that contractor's license number has pulled in the last 12 months. An experienced ADU builder has a permit trail. A scam operator usually doesn't, and that single phone call surfaces it faster than any online review ever will.
