San Diego is a national leader in ADU construction, with more ADU permits issued per capita than almost any other US city. The city has proactively streamlined its ADU regulations beyond state minimums.
Zoning & Size Requirements
| Allowed Zones | All residential zones; also allowed in some commercial mixed-use zones |
| Max Size (Detached) | 1,200 sq ft |
| Max Size (Attached) | 1,200 sq ft or 50% of primary dwelling |
| Max Size (JADU) | 500 sq ft |
| Max Height | 25 ft (2 stories) |
| Max Units | 1 ADU + 1 JADU per single-family lot; up to 8 on multifamily |
Setback Requirements
| Rear Setback | 4 ft |
| Side Setback | 4 ft |
| Front Setback | Per underlying zone |
| Parking Required | No parking required |
| Owner Occupancy | Not required |
| Min Lot Size | No minimum lot size for JADUs |
Permit Process & Fees
| Approval Process | Ministerial review; no discretionary approval needed |
| Review Timeline | 60 days (often faster) |
| Permit Fees | $3,500-$12,000 |
| Impact Fees | Waived for units under 750 sq ft |
| Plan Check | Standard plan check included |
| Pre-Approved Plans | Yes — companion unit program with pre-approved designs |
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Construction Costs
| Average Build Cost | $120,000-$300,000 |
| Cost per Sq Ft | $180-$350 |
| Garage Conversion | $70,000-$160,000 |
| Prefab ADU (Installed) | $90,000-$220,000 (installed) |
Finance Your ADU Project
Most ADU projects are funded through HELOCs, construction loans, or cash-out refinancing. Compare rates from top lenders in minutes.
Compare ADU Financing Options →Rental Income Potential
| Avg Rent (1 Bedroom) | $1,600-$2,200/mo |
| Avg Rent (2 Bedroom) | $2,000-$2,800/mo |
| Short-Term Rental | Allowed with STRO license in certain zones |
| Est. Annual ROI | 7-11% annual return |
Explore Prefab ADU Options
Prefab ADUs can save 20-40% vs. traditional construction and cut build time in half. Compare top prefab manufacturers.
Compare Prefab ADUs →Recent Law Changes
What's Changed Recently
- SB 1211 (Jan 2025): Up to 8 ADUs on multifamily lots
- AB 1033 (2024): Separate ADU sale provisions
- City expanded pre-approved plan library (2024)
- Streamlined online permit portal launched (2024)
Tips for Building an ADU in San Diego
- San Diego's moderate build costs + solid rents = excellent ROI
- The online permit portal makes San Diego one of the easiest cities to get ADU approval
- Climate allows for cost-effective outdoor spaces that boost rental value
- Look into the companion unit pre-approved plans for fastest approval
Frequently Asked Questions
Can I build an ADU in San Diego?
Yes. ADUs are allowed in All residential zones; also allowed in some commercial mixed-use zones in San Diego. The maximum size for a detached ADU is 1,200 sq ft. No owner-occupancy is required.
How much does an ADU cost in San Diego?
ADU construction in San Diego typically costs $120,000-$300,000. Garage conversions run $70,000-$160,000, and prefab ADUs cost $90,000-$220,000 (installed).
How much can I rent an ADU for in San Diego?
Average ADU rents in San Diego are $1,600-$2,200/mo for a 1-bedroom and $2,000-$2,800/mo for a 2-bedroom unit.
Do I need parking for an ADU in San Diego?
No parking required. Check with San Diego planning department for the latest California ADU parking rules, as many states have relaxed requirements in recent years.
How long does it take to get an ADU permit in San Diego?
The permit review timeline in San Diego is 60 days (often faster). Fees range from $3,500-$12,000.
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