Zoning & Size Limits
| Requirement | San Diego, CA | San Jose, CA |
|---|
| Allowed Zones | All residential zones; also allowed in some commercial mixed | All residential zones (R-1, R-2, R-M, R-MH) |
| Max Size (Detached) | 1,200 sq ft | 1,200 sq ft |
| Max Size (Attached) | 1,200 sq ft or 50% of primary dwelling | 1,200 sq ft or 50% of primary dwelling |
| Max Height | 25 ft (2 stories) | 25 ft for detached |
| Parking Required | No parking required | No parking required |
| Owner Occupancy | Not required | Not required |
Setback Requirements
| Setback | San Diego, CA | San Jose, CA |
|---|
| Rear Setback | 4 ft | 4 ft |
| Side Setback | 4 ft | 4 ft |
| Front Setback | Per underlying zone | Per underlying zone |
Permits & Timeline
| Detail | San Diego, CA | San Jose, CA |
|---|
| Permit Timeline | 60 days (often faster) | 60 days |
| Permit Fees | $3,500-$12,000 | $4,000-$14,000 |
| Impact Fees | Waived for units under 750 sq ft | Waived for units under 750 sq ft |
| Pre-Approved Plans | Yes — companion unit program with pre-approved des | Limited pre-approved options available |
Construction Costs
| Cost | San Diego, CA | San Jose, CA |
|---|
| Avg Build Cost | $120,000-$300,000 | $180,000-$400,000 |
| Cost Per Sq Ft | $180-$350 | $250-$450 |
| Garage Conversion | $70,000-$160,000 | $100,000-$220,000 |
| Prefab ADU | $90,000-$220,000 | $130,000-$300,000 |
Rental Income Potential
| Rental | San Diego, CA | San Jose, CA |
|---|
| 1BR Avg Rent | $1,600-$2,200/mo | $2,000-$2,800/mo |
| 2BR Avg Rent | $2,000-$2,800/mo | $2,500-$3,500/mo |
| Short-Term Rentals | Allowed with STRO license in certain zones | Restricted; requires transient occupancy tax registration |
| Est. ROI | 7-11% annual return | 5-9% annual return |
Which City Is Better for ADUs?
San Diego scores 9/10 while San Jose scores 8/10 on our ADU-friendliness index.
San Diego edges ahead overall. Both cities offer viable ADU development opportunities — the best choice depends on your specific property, budget, and goals.
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