Garage Conversion to ADU in San Diego (2026): Complete Guide
Vision ADU San Diego ·
Garage conversion is the lowest-cost ADU path in San Diego
For SD homeowners with an existing garage, conversion is the fastest, cheapest route to a permitted, rentable ADU.
Typical SD garage conversion costs in 2026
- 300–400 sf garage: $130k–$175k
- 400–500 sf garage: $150k–$215k
- 500–600 sf garage (oversized 2-car): $175k–$245k
Costs include design, permits, full mechanical/electrical/plumbing upgrade, finishes, and final inspections.
Timeline
- Pre-construction (design + permit): 8–14 weeks
- Construction: 8–12 weeks
- Total: 4–6 months
What gets replaced/upgraded
- Garage door → insulated wall with windows
- Concrete slab → leveled, insulated subfloor (sometimes)
- Roof insulation
- New electrical sub-panel (200A)
- New plumbing for kitchen and bath
- HVAC (typically mini-split)
- Egress windows in sleeping area
- Title 24 energy compliance
- Fire-rated wall if attached to main house
ROI for SD garage conversions
| Cost | Rent | Years to Break Even |
|---|---|---|
| $160k | $2,200/mo | ~7 years |
| $190k | $2,500/mo | ~7 years |
| $220k | $2,800/mo | ~7 years |
Plus immediate home value gain of 110–130% of project cost.
Most common SD cities for garage conversions
- City of San Diego (Clairemont, Linda Vista, Allied Gardens)
- Chula Vista (older western neighborhoods)
- La Mesa (Mt. Helix, Lake Murray)
- El Cajon (most established neighborhoods)
- North Park / South Park (challenging due to small lots but high ROI)
Vision ADU specializes in SD garage conversions
Book a free site evaluation and we will confirm if your garage qualifies.
Frequently Asked Questions
How much does a garage conversion cost in San Diego in 2026? $130k–$245k depending on size and finish level.
How long does a garage conversion take in San Diego? 4–6 months from contract to keys.
Do I need replacement parking after converting my garage? No — California state law forbids cities from requiring replacement parking.
Can I rent my converted garage ADU? Yes — once permitted, you can rent for 30+ day terms.
Will the conversion increase my property tax? Only on the new value added — typically $1,500–$2,500/year increase.