San Diego
ADU cost in San Diego, 2026
San Diego is one of California's most active ADU markets — SnapADU alone has built 100+ ADUs in the county since 2020. The city's Development Services Department (DSD) processes standard ADU permits in 50–75 days, with Coastal Overlay Zone projects requiring concurrent Coastal Development Permit review per AB 462.
Typical 2026 all-in cost
$100,000 – $400,000
250–450 $/sq ft
DQB Jan 2026; SnapADU 2025-2026.
Dynamic Quality Builders (2026) puts San Diego construction costs slightly below LA County: per-sqft labor rates run lower, and Coastal Zone properties aside, the permitting environment is more predictable than LA's. Typical 2026 ranges: garage conversion $100,000–$180,000, attached ADU $175,000–$300,000, detached ADU $250,000–$400,000.
By type and tier
| Type or tier | Range | Notes |
|---|---|---|
| Garage conversion | $100K–$180K | |
| Attached ADU | $175K–$300K | |
| Detached ADU | $250K–$400K | |
| JADU | $50K–$100K |
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San Diego FAQ
- How long does it take to build an ADU in San Diego?
- Total 10–18 months from first conversation to certificate of occupancy. Design 2–5 months, permitting 3–9 months (faster on standard ADUs; slower in Coastal Zone), construction 6–10 months. SnapADU has the most published timeline data for the San Diego market.
- Do I need a Coastal Development Permit?
- Only if your property sits in the California Coastal Zone. The CDP is reviewed concurrently with the building permit under AB 462's 60-day mandate, but in practice coastal projects still move slower than inland.
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