Accessory Dwelling Units (ADUs) have exploded in popularity across San Diego since California's 2020 ADU reform laws removed most local barriers to construction. If you own a single-family home in San Diego, you almost certainly qualify to build an ADU — and the financial case has never been stronger.
Types of ADUs Popular in San Diego
Detached ADU: A standalone structure in the backyard. Most popular for rental income. Typical size: 400–1,200 sq ft.
Attached ADU: Added to the primary residence. Good for in-law suites.
Garage Conversion ADU: Converting an existing garage is the most cost-effective option, typically 30–40% cheaper than new construction.
Junior ADU (JADU): Up to 500 sq ft carved from within the existing home. Minimal permitting, fastest to complete.
ADU Construction Costs in San Diego (2025)
| ADU Type | Cost per Square Foot | Typical Total |
|---|---|---|
| Garage conversion | $150 – $250 | $30,000 – $60,000 |
| Attached ADU | $250 – $350 | $80,000 – $180,000 |
| Detached ADU | $300 – $450 | $120,000 – $250,000 |
San Diego ADU Permit Process
1. Submit plans to the City of San Diego Development Services or your city's planning department
2. Environmental and zoning review (typically 4–8 weeks)
3. Building permit issuance
4. Construction phase inspections
5. Certificate of occupancy
Pro tip: Pre-approved ADU plans from the City of San Diego's Standard Plan Program can cut permitting time from months to weeks.
ADU Rental Income Potential in San Diego
With San Diego's median 1-bedroom rental at $2,400/month (Zillow, Q1 2025), a well-built ADU can generate $28,000+ per year. This means a $150,000 detached ADU pays for itself in approximately 5 years while permanently adding value to your property.
Is an ADU Right for Your Property?
Transform Remodeling Inc provides free ADU feasibility assessments. We review your lot size, setbacks, utility connections, and HOA rules (if applicable) to give you an honest picture of what's possible before you spend a dollar.
