Junior ADU

Junior ADU conversion across San Diego County

A junior ADU is a 150 to 500 square foot unit built inside an existing single-family home. An attached garage counts as part of that home, so it can become a JADU. A detached garage cannot. The unit needs its own exterior entrance and an efficiency kitchen. It may share a bathroom with the house. Owner occupancy depends on whether sanitation is shared. We match San Diego County homeowners with insured local crews for drawings, permits, and the conversion itself. Garage Convert SD is a referral service. Verify any matched professional at cslb.ca.gov. The City of San Diego program page is sandiego.gov/development-services/news-programs/programs/companion-junior-units.

Also called JADU, junior ADU, attached ADU, in-law unit, or mother-in-law suite across San Diego County. Same job, different names.

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Interior of an attached garage being converted to a junior ADU in San Diego County with framing, insulation, and a new kitchenette rough-in underway

What's included in junior ADU conversion?

JADU-specific permit drawings confirming the unit is within 500 square feet and contained within the existing structure
Garage door removal and wall infill with framing, insulation, drywall, and exterior finish to close the opening
Kitchenette rough-in connecting to the main home plumbing with an efficiency sink and countertop cooking setup
Bathroom connection options sharing the main home bath or adding a half-bath within the JADU footprint
Insulation, drywall, and fire-rated assemblies meeting California JADU code requirements
Flooring, interior finish, and final permit inspection sign-off

When do you need junior ADU conversion?

Your garage is attached to the house and you want a legal unit of 500 square feet or less inside the existing walls
A family member needs a private living space with an efficiency kitchen and can share, or not share, the main bathroom
You want a rental unit on the JADU path rather than a full ADU with a complete kitchen and bath
Your property has an attached garage and limited setback room for a detached ADU or new construction
You want a permitted attached-garage unit and are willing to record the JADU deed restriction

What do homeowners ask about Junior ADU?

What is the difference between a JADU and a full ADU?

A JADU is limited to 500 square feet, must sit inside a single-family residence (an attached garage counts), needs an efficiency kitchen and its own entrance, and can share a bathroom with the main home. A full ADU can be attached or detached, needs complete independent living facilities, and in the City of San Diego is listed from 150 to 1,200 square feet. A JADU cannot be sold separately from the house. Owner occupancy for a JADU depends on whether it shares sanitation with the main home. A full ADU cannot carry a local owner-occupancy rule.

How much does a junior ADU conversion cost in San Diego?

A junior ADU conversion in San Diego County typically runs $50,000-$90,000 depending on whether you share the main home bathroom or add a half-bath, the kitchenette scope, and the interior finish level. The licensed pro you hire confirms the price in writing. Garage Convert SD sets no prices.

Can I rent out a junior ADU in San Diego?

You can rent a JADU, but occupancy rules are not the same as a full ADU. If the JADU shares sanitation with the main house, the owner must live in either the house or the JADU. If the JADU has its own bathroom, that owner-occupancy rule does not apply. Government agencies, land trusts, and housing organizations have a separate waiver. A recorded deed restriction also bars selling the JADU apart from the house. Full ADUs cannot be given a local owner-occupancy requirement. Cities can still require rentals of 30 days or longer.

Does a junior ADU need its own bathroom?

No. A JADU can share a bathroom with the main home if the unit has interior access to it. If you want a private bathroom within the JADU footprint, a half-bath can be added within the 500 square foot limit. The licensed pro you hire confirms the plumbing scope in writing.