ADUs (Accessory Dwelling Units) are one of the best investments for California homeowners. Here's what they actually cost to build, from simple garage conversions to custom detached units.
Garage Conversion ADU Costs
Converting an existing garage to an ADU typically costs $100,000-180,000 in Southern California. This includes foundation work, utilities, bathroom/kitchen, HVAC, and finishes. Two-car garages converting to larger ADUs run $150,000-250,000.
Detached ADU Construction
Ground-up detached ADUs cost $200,000-400,000 depending on size and finishes. A basic 400 sq ft studio ADU might cost $180,000-250,000. A full 1,200 sq ft two-bedroom ADU typically runs $300,000-450,000.
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Permits & Fees
California ADU permits have been streamlined but still cost $5,000-15,000 in fees. Design and engineering add $8,000-20,000. Total soft costs typically run 15-20% of construction cost.
Return on Investment
ADUs in Southern California can generate $1,500-3,500/month in rental income. Many homeowners recover construction costs within 8-15 years while adding 25-35% to property value.
Final Thoughts
ADUs represent one of the best investments for California homeowners. Despite high upfront costs, the combination of rental income and property value increase makes them financially compelling.
Frequently Asked Questions
Costs vary based on scope and location. Consult with professionals for accurate estimates.
