What Is an ADU?
An Accessory Dwelling Unit (ADU) is a secondary housing unit built on a single-family residential lot. ADUs can be detached structures, attached additions, garage conversions, or junior ADUs within your existing home. In San Diego, ADUs can be up to 1,200 square feet and must include a kitchen, bathroom, and sleeping area.
How Much Does an ADU Cost?
ADU costs in San Diego typically range from about $120,000 for a garage conversion to roughly $520,000 for a larger 1,200 sq ft detached or two-story build. Compact detached ADUs start at $175,000, attached ADUs start around $220,000, and larger family-ready plans scale from there based on layout, site work, and finish level.
How Long Does It Take?
The typical ADU timeline in San Diego is 12-16 months from start to finish. This includes 1-2 months for design and engineering, 6-9 months for permitting (the longest phase), and 3-4 months for construction. Our team manages every step of the process.
Permits & Regulations
All ADUs in San Diego require building permits. California state law (AB 68, SB 13) has streamlined the ADU approval process, eliminating many previous barriers. San Diego allows ADUs on most single-family lots without additional parking requirements. We handle the entire permitting process for you.
Benefits of Building an ADU
- Generate roughly $2,000-$6,000/month depending on the ADU product and lease strategy
- Increase property value by 20-35%
- Provide housing for family members with privacy
- Average payback period of 5-8 years
- No additional parking required in most cases
- Streamlined permit process under California law