How to choose the best ADU builder in San Diego
Who are the best ADU builders in San Diego?
The best builder for you is one with an active CSLB license, a visible track record of City of San Diego ADU permits, a fixed itemized scope and strong verified reviews. In 2026 the City issued 1134 permits adding 1711 ADU units, so experienced firms are easy to find in public records. We list permit holders on local firms; we publish no paid rankings.
Our premium screening bar
- Active CSLB license (B general) with bond and workers' comp. Check at cslb.ca.gov.
- Recent San Diego ADU permits in their name, ideally of your ADU type.
- 4.8+ rating with 50+ reviews and finished projects you can visit.
- Itemized fixed-scope bid: design, engineering, City fees, utilities, solar, finishes.
- Legal deposit: California caps most home-improvement down payments at 10% or $1,000, whichever is less.
Red flags
- A bid far below the 2026 City median of $120,900 for a single ADU without saying what is excluded.
- Asking you to pull the permit as owner-builder.
- No written schedule or change-order process.
See also questions to ask and fair quote checklist.
Talk to vetted local pros
Questions San Diego homeowners ask
How do I verify an ADU builder?
Look up the license on the CSLB site, confirm bond and workers' comp, and ask for addresses of recent San Diego ADU permits.
How much should an ADU builder deposit be?
In California, generally no more than 10% of the contract or $1,000, whichever is less.
Design-build or separate architect?
Design-build gives one point of responsibility and often faster permitting; a separate architect gives more design control.
Meet builders who pass the bar
We introduce up to 3 builders that meet our screening criteria. Free.