Vision ADU San Diego - Building Your Vision
Vision ADUSan Diego

Junior ADU (JADU) vs. Standard ADU

Compare Junior ADUs and full-size ADUs — size, cost, income potential, and which makes sense for your property.

California allows two types of accessory dwelling units: the standard ADU (up to 1,200 sq ft) and the Junior ADU or JADU (up to 500 sq ft within your existing home). Understanding the differences helps you choose the right option — or you can build both on the same property.

Feature
Junior ADU (JADU)
Standard ADU
Max Size
500 sq ft
1,200 sq ft
Typical Cost
varies
varies
Timeline
3–5 months
6–12 months
Location
Within existing home
Detached or attached
Kitchen Requirement
Efficiency kitchen only
Full kitchen required
Bathroom
Can share with main house
Must have its own
Separate Entrance
Required
Required
Fire Separation
Required between JADU and main house
N/A for detached
Rental Income
varies
varies
Property Value Increase
varies
varies
Can Build Both?
Yes, plus a standard ADU
Yes, plus a JADU
Owner Occupancy Required
Yes (owner lives in main house or JADU)
No (until 2030)
Impact Fees
Exempt (under 750 sq ft)
Exempt if under 750 sq ft
AB 1033 Eligible
May be eligible
Yes, primary AB 1033 candidate

Junior ADU (JADU)

Pros

Lowest cost
Fastest to build (3–5 months)
No new foundation or structure needed
No impact on yard space
Exempt from most impact fees
Can be built IN ADDITION to a standard ADU

Cons

Limited to 500 sq ft
Must be within existing home
Owner occupancy required
Smaller kitchen (efficiency only)
Lower rental income
Less privacy for both units

Best For

Homeowners on a tight budget who want to create a small rental unit quickly within their existing home, or who want to maximize units by adding a JADU alongside a full ADU.

Standard ADU

Pros

Up to 1,200 sq ft of living space
Fully independent unit
Higher rental income
No owner occupancy requirement
Best candidate for AB 1033 sale
Complete design flexibility

Cons

Higher cost
Longer timeline (6–12 months)
May reduce yard space (if detached)
More complex permitting
New construction requires foundation

Best For

Homeowners who want maximum rental income, a fully independent living space, and the ability to sell the unit separately under AB 1033.

Our Verdict

The best strategy? Build both. California law allows one JADU and one ADU on the same single-family property. Start with a JADU for quick, affordable rental income, then build a full ADU when you're ready. Together, you could generate a meaningful amount in rental income — turning your single-family home into a three-unit property.

Frequently Asked Questions

Not Sure Which Option Is Right for You?

Book a free consultation and our experts will assess your property and recommend the best approach.

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