Best ADU Builder in San Diego | Instant Living

Looking for the best ADU builder in San Diego? Instant Living handles ADU design, permits, site work, utilities, installation, and inspections for a faster, simpler turnkey backyard home.

Building an Accessory Dwelling Unit (ADU) in San Diego requires navigating a mix of city zoning and density rules. Homeowners in the City of San Diego can generally build up to 150 to 1,200 square feet, and must abide by strict lot-size-based unit caps that limit properties to 4–6 ADUs depending on the lot size.

Cost & Permitting Average Cost: Expect to invest between $375 to $600+ per square foot for turnkey construction. A standard build typically costs between $300,000 and $450,000+ covering design, permits, site preparation, and utility hookups.

Financial Assistance: The San Diego Housing Commission (SDHC) ADU Finance Program provides up to $250,000 in construction loans and no-cost technical help for eligible low-income homeowners.

Property Taxes: Building an ADU does not trigger a reassessment of your primary home; your property taxes will only increase based on the added assessed value of the new unit.City Size & Density Regulations

Size Limits: Both attached and detached ADUs must be a minimum of 150 sq. ft. and can go up to 1,200 sq. ft.. If you are converting an existing accessory structure or part of your primary residence, the 1,200 sq. ft. cap generally does not apply.

Density Caps: The City of San Diego sets hard unit caps depending on your lot size:Under 8,000 sq. ft.: Up to 4 ADUs8,000 – 10,000 sq. ft.: Up to 5 ADUsOver 10,000 sq. ft.: Up to 6 ADUs

Junior ADUs (JADUs): A JADU up to 500 sq. ft. can be built entirely within your existing single-family home's footprint (e.g., converted garage or bedroom).

Next Steps & Resources Review Requirements: Detailed zoning and development guidelines can be accessed directly via the City of San Diego Accessory Dwelling Units Overview.

City Bulletins: For specific spatial constraints, setbacks, and floor area ratio (FAR) exceptions, refer to the City of San Diego Information Bulletin 400.Unincorporated County: If you live outside city limits, review the County of San Diego ADU Information for slightly different local guidelines.