Detached ADU
Standalone structure, fully independent, maximum privacy. Ideal for rental income or high-end guest suites where separation from the main house is desired.
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Editorial / Architecture
A clear breakdown of the main Accessory Dwelling Unit (ADU) types based on California standards and real-world use cases.
Accessory Dwelling Units (ADUs) come in several forms, each with different cost levels, permitting paths, and design flexibility. Understanding the differences is key to choosing the right approach for your property.

Standalone structure, fully independent, maximum privacy. Ideal for rental income or high-end guest suites where separation from the main house is desired.
Shares a wall, cost-efficient, and leverages existing utility lines and structural components, making the faster path in some districts.
Garage, basement, or attic conversion using existing structure. Often the fastest route to completion by utilizing the footprint already available.
Inside existing home, max 500 sq ft, lower cost. Requires an efficiency kitchen and can share sanitation facilities with the primary residence.
Privacy Trend
Detached > JADU
Cost Factor
JADU is most accessible
Design Flexibility
High for new builds
Regulations vary by city. While California state law has eased ADU development, local ordinances may dictate specific setbacks, height limits, and parking requirements. Always consult local municipal codes before beginning design.