Junior ADUs (JADUs) in San Diego
A junior ADU turns space you already have, like a bedroom, a wing of the house or an attached garage, into a separate small home with its own entrance. It’s the lowest-cost way to add a legal second unit.
JADUs from $50,000. Every project is scoped and quoted individually. City permits and fees are billed separately.
What counts as a JADU
- Up to 500 square feet, created within your existing home. Under state law, an attached garage counts as part of the home.
- Its own entrance, separate from the main entrance.
- An efficiency kitchen: a cooking facility with appliances, a food prep counter and storage cabinets.
- Its own bathroom, or a bathroom shared with the main house.
- One JADU per single-family lot, and it can sit alongside a regular ADU.
As of January 2026, state law only requires the owner to live on the property if the JADU shares a bathroom with the main house. Local rules can add detail, so we confirm exactly what applies to your home during feasibility.
What a JADU costs
from $50,000
The biggest variables are whether the JADU gets its own bathroom, how far plumbing has to run, and whether a garage slab needs work. A bedroom conversion with a shared bath sits at the low end; a garage conversion with a full bath sits higher. An attached garage turned into a unit of up to 500 square feet can be a JADU. A larger conversion, or a detached garage, is priced as a garage conversion ADU, from $80,000.
How long it takes
Because it’s inside the existing structure, a JADU is usually the fastest legal unit to permit and build. We give you a written schedule after feasibility.
JADU, garage conversion or full ADU?
JADU (up to 500 sq ft, inside the home)
A junior ADU carved out of existing space, with its own entrance and an efficiency kitchen.
Garage conversion ADU
Turning an attached or detached garage into a legal living unit.
Attached ADU
A new unit built onto the existing house.
Detached ADU
A standalone backyard home, from foundation to finish.
Every project is scoped and quoted individually. City permits and fees are billed separately.
See every starting price in the cost guide
More on ADUs and additions · A detached ADU we’re building in Del Mar
JADU questions
Why would I build a JADU instead of an ADU?
Cost and speed. A JADU uses structure you already own, so there’s no new foundation or roof. If you need a private space for a family member or a rental without building a new structure, it’s the most efficient route.
Can I rent out a JADU?
Yes, as a longer-term rental. State law requires any rental of a JADU to be for more than 30 days, so it can’t be used as a short-term or vacation rental. If the JADU shares a bathroom with the main house, the owner also has to live in the house or in the JADU.
Do I need parking for a JADU?
Generally no additional parking is required. We confirm the specifics for your lot during feasibility.
Find out if your home can fit a JADU
Send us a few details about the project and we’ll set up a visit to look at the space.
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