Why vetting your ADU contractor is the most important step
An ADU is a real building — foundation, framing, electrical, plumbing, energy compliance, and city inspections. The contractor you choose decides whether it finishes cleanly and adds equity, or turns into a stalled, over-budget headache. With demand at record highs across Southern California, plenty of unlicensed operators are chasing the "ADU contractor near me" searches. This 12-point checklist is how you separate the professionals from the risks.
Work through every point below before you sign a contract. If you're still deciding between a generalist and a specialist, read general contractor vs. ADU specialist first.
1. Look up the CSLB license
The California Contractors State License Board (CSLB) is the foundation of the whole process. Go to cslb.ca.gov, use the "Check a License" tool, and enter the contractor's number. Confirm it is active, in good standing, and classified B (General Building) — the correct classification for ADU construction and garage conversions. If the contractor won't give you a license number, stop there.
2. Confirm the license matches the business
The name on the license should match the company you're actually hiring. Check that the responsible managing officer or employee (RMO/RME) and business name line up. A number that belongs to a different entity is a warning sign.
3. Verify the contractor's bond
Every licensed California contractor must carry a contractor's license bond. On the CSLB record, confirm the bond is active and current. The bond exists to protect you if the contractor abandons the job or performs defective work.
4. Confirm insurance — liability and workers' comp
Ask for a Certificate of Insurance (COI) and confirm two things:
- General liability covers property damage during construction.
- Workers' compensation is active (or a valid exemption is on file). This is critical — without workers' comp, you could be held liable if a worker is injured on your property.
Have the COI list you as certificate holder and confirm the dates cover your full build window.
5. Check BuildZoom and third-party ratings
Independent platforms like BuildZoom aggregate license data, permit records, and project history into a single profile and score. Use them to sanity-check what the contractor tells you. A strong, independently verified track record — for example, ranking in the top few percent of California contractors — is a meaningful signal.
6. Read reviews across multiple platforms
Don't rely on a single testimonial page. Cross-reference Google reviews, Yelp, and the Better Business Bureau. Look for patterns in how the contractor handles problems, not just the star average. A steady stream of recent, detailed reviews beats a handful of glowing ones from years ago.
7. Verify the project portfolio in person
Photos are easy to borrow. Ask to see completed ADUs — ideally near your city — and, when possible, drive by or speak with past clients. A real ADU builder is proud to show finished work; browse ours at the Vision ADU portfolio. Confirm the projects shown are genuinely theirs.
8. Pull the permit history
Legitimate ADUs are permitted. Ask which cities the contractor has recently built in and confirm they know how to navigate plan check. Cities like Sherman Oaks, Pasadena, Encino, North Hollywood, Woodland Hills, Santa Monica, and Calabasas each have their own review habits. A contractor who has permitted work in your city already knows the local checker's expectations.
9. Confirm ADU-specific experience
ADUs carry compliance traps that a general remodel doesn't: setbacks, fire separation, utility connections, and Title 24 energy compliance. Ask how many ADUs they completed in the last 12 months and whether any required a variance. Recent, repeated ADU experience is what you want.
10. Require an itemized written estimate
A professional estimate breaks the project into line items — site work, foundation, framing, mechanical/electrical/plumbing, finishes, and permits. Be wary of a single lump-sum number with no breakdown; it hides change-order risk and makes it impossible to compare bids fairly.
11. Review the contract before you sign
A real ADU contract includes the full scope of work, referenced plans and specifications, a payment schedule tied to completed milestones, start and completion dates, a written change-order procedure, warranty terms, permit responsibility, and the contractor's license, bond, and insurance details. If the "contract" is a one-line total on an estimate, it is not enough.
12. Watch for red flags
End the conversation if you see any of these:
- Pressure to sign within 24 hours
- Refuses to pull permits or suggests "permit later"
- Cash-only or heavily front-loaded deposits
- No verifiable license number
- A bid dramatically below every other bid on the same scope
- No physical office, showroom, or verifiable portfolio
Put it all together
Run all twelve points, get three bids on the exact same scope, and choose the contractor who is transparent at every step. When you're ready, compare your shortlist against the criteria in our ADU contractor near me guide, see where we build across our service areas, and book a free site evaluation.
Frequently Asked Questions
How do I check if an ADU contractor is licensed in California?
Use the "Check a License" tool at cslb.ca.gov. Enter the license number and confirm it is active, in good standing, and classified B (General Building). Verify the business name matches and review the bond, workers' compensation, and any disclosures on the record.
What license classification do I need for an ADU?
A B (General Building) classification is the standard for ADU new construction and garage conversions in California, since the work spans multiple trades. Confirm the classification on the CSLB record before hiring.
What is BuildZoom and how does it help me vet a contractor?
BuildZoom is an independent platform that combines license data, permit history, and project records into a contractor profile and score. It's a useful third-party cross-check against what a contractor tells you — a top-ranked profile is a strong signal.
How can I verify a contractor's past ADU projects?
Ask for a portfolio of completed ADUs, request addresses or references near your city, and drive by or call past clients when possible. Cross-reference the work against their permit history and independent reviews.
What insurance should an ADU contractor carry?
A contractor's license bond, general liability insurance, and workers' compensation. Request a Certificate of Insurance naming you as certificate holder and confirm the coverage dates span your entire construction window.
What are the biggest red flags when hiring an ADU contractor?
Pressure to sign immediately, refusing to pull permits, cash-only or front-loaded deposits, no verifiable license number, and a bid dramatically lower than every other bid on the same scope of work.
How many ADU bids should I get?
Three bids on the identical scope is the sweet spot. It gives you enough to compare quality and clarity without turning the search into an endless comparison exercise.