What Questions Should I Ask an ADU Contractor in San Diego Before I Sign a Contract?

Building an accessory dwelling unit is one of the biggest investments you can make in your property. It can add rental income, house family, and raise your home's value. But the contract you sign decides whether the project runs smoothly or turns into months of delays and surprise charges.

Before you commit, ask the right questions. Below are the questions to ask an ADU contractor in San Diego, grouped by topic, with an explanation of what a good answer looks like.

Questions About License, Insurance, and Experience

1. Are you licensed in California, and can I verify it?

Every contractor taking on work over $1,000 in California must hold a license from the Contractors State License Board (CSLB). Ask for the license number and look it up on the CSLB website. Check that the status is active, the classification fits the work, and there are no disciplinary actions. For example, XLNC Builder holds a Class B General Building license (#1153455), which covers projects that combine multiple trades like an ADU.

2. Are you bonded and insured?

Ask for proof of general liability insurance and the contractor's license bond. If the contractor has employees, ask for proof of workers' compensation coverage too. Without it, you could be exposed to liability if someone is hurt on your property.

3. How many ADUs have you built in San Diego?

ADU construction is different from a standard remodel. It involves separate utility connections, setbacks, fire requirements, and city review. Ask for recent San Diego examples, photos, and references from homeowners with similar projects. You can also browse a contractor's project portfolio before you call.

Questions About Permits and Design

4. Do you handle design and permitting, or do I need to hire separately?

Some contractors manage everything from plans to final inspection. Others expect you to bring approved drawings. Know which one you are hiring, because it changes your budget and timeline. A team that offers architectural design and construction under one roof usually means fewer handoffs and fewer gaps in responsibility.

5. Who is responsible for permit fees and plan check corrections?

Plan check often returns comments that require revisions. Ask who pays for those changes, who communicates with the city, and how the contract treats delays caused by review cycles. Our guide to the San Diego ADU permit process explains the steps, fees, and typical timelines so you know what to expect.

6. Does the plan comply with current San Diego ADU rules?

Zoning, height limits, setbacks, and parking requirements change over time. A good contractor stays current and can explain how the rules apply to your specific lot. Read through the latest San Diego ADU rules before your meeting so you can ask informed follow-up questions.

Questions About Pricing and Payments

7. Is your quote fixed-price or cost-plus?

A fixed-price contract sets the total cost up front. A cost-plus contract bills you for actual expenses plus a markup, which can make final costs harder to predict. Ask which model applies and get the answer in writing.

8. What exactly is included in the price?

Request a line-by-line scope. Confirm whether the price covers plans, permits, utility hookups, site work, flooring, fixtures, appliances, landscaping, and cleanup. Vague allowances are a common source of surprise costs. To check whether a quote is realistic, compare it with our breakdown of ADU costs in San Diego.

9. What is the payment schedule?

California law limits the down payment on a home improvement contract to 10 percent of the contract price or $1,000, whichever is less. The remaining payments should be tied to completed milestones, not calendar dates. Be cautious of any contractor who asks for large payments up front. Rules can change, so confirm the current limits with the CSLB.

10. How do you handle change orders and unexpected conditions?

Hidden issues like old plumbing, soil conditions, or utility conflicts can appear once work begins. Ask how the contractor prices and approves changes. The best answer is a written change order that you sign before any extra work starts.

Questions About Timeline and Communication

11. What is the realistic timeline from signing to move-in?

Ask for separate estimates for design, permitting, and construction. Permitting is often the least predictable phase, so a contractor who gives you a range and explains the variables is more trustworthy than one who promises a fixed date. Our ADU construction guide for San Diego covers each phase in detail.

12. Who will be my main point of contact?

Find out who manages day-to-day progress, how often you will get updates, and how quickly they respond to questions. Clear communication prevents most disputes.

13. Do you use your own crew or subcontractors?

Neither answer is wrong, but you should know who will be on your property. Ask how the contractor vets subcontractors and who is accountable for their work.

Questions About Warranty and Contract Terms

14. What warranty do you offer, and what does it cover?

Ask for the warranty terms in writing, including the length of coverage, what is included, and how to submit a claim. Workmanship, materials, and manufacturer warranties often work differently.

15. What does the contract say about delays, disputes, and cancellation?

Read the full contract before signing. It should include the scope of work, total price, payment schedule, start and estimated completion dates, change order process, and your right to cancel. In California, you generally have a three business day right to cancel a home improvement contract signed at your home. If anything is unclear, ask for it to be revised before you sign.

Red Flags to Watch For

• No written contract or a vague scope of work
• Pressure to sign immediately or accept a "today only" discount
• A request for a large deposit or cash-only payments
• Unwillingness to share a license number, insurance, or references
• An unusually low bid compared with other quotes

Compare Quotes the Right Way

Get at least three written bids and compare them on scope, not just price. A lower quote that leaves out permits, site work, or finishes can end up costing more than a complete one. Use the questions above as a checklist in every meeting so you can compare answers side by side.

Ready to Talk to a Licensed San Diego ADU Builder?

XLNC Builder is a licensed, bonded, and insured San Diego contractor that offers design, permitting support, and construction for custom ADUs. We are happy to answer every question on this list, walk you through a transparent quote, and show you what the process looks like from start to finish. Request a free quote or call (619) 836-0099 to get started.

Frequently Asked Questions

How many quotes should I get before choosing an ADU contractor in San Diego?

Get at least three written quotes. Comparing them side by side helps you spot missing scope items, unrealistic pricing, and differences in warranty or timeline.

How can I check if an ADU contractor is licensed in California?

Visit the CSLB website and search by license number or business name. Confirm the license is active, the classification fits the work, and that the contractor has a valid bond and insurance on file.

How much deposit should I pay an ADU contractor?

California law generally caps the down payment on a home improvement contract at 10 percent of the contract price or $1,000, whichever is less. After that, payments should follow completed project milestones. Confirm current limits with the CSLB before signing.

Should the ADU contractor handle permits?

Many homeowners prefer a contractor who manages design and permitting along with construction, since it reduces coordination problems. Whichever route you choose, make sure the contract states clearly who is responsible for plans, fees, and plan check revisions.

What should an ADU contract include?

A solid contract lists the detailed scope of work, total price, payment schedule, start and completion dates, change order process, warranty terms, license number, insurance details, and your right to cancel. Do not sign until every item is clear and in writing.