A junior accessory dwelling unit, or JADU, is a small living unit created inside the walls of your existing single-family home. Think of a primary suite with its own outside door and a compact kitchen, or a den and bedroom closed off from the rest of the house.
What makes a space a junior ADU
- Up to 500 sq ft, within the existing home (an attached garage counts)
- Its own exterior entrance, plus an optional interior door to the main house
- An efficiency kitchen: sink, cooking appliance, food prep counter and storage
- Bathroom: its own, or shared with the main house
- No impact fees for JADUs under state law
Who JADUs are perfect for
- Parents or grandparents who want privacy but need family close by
- Adult children saving for their own place
- Caregivers who need to live on site
- Homeowners who want modest rental income without building in the yard
Because a JADU uses space you already have, there is no new foundation and usually no new roof. That keeps both the cost and the timeline down, and you keep your backyard.
Common Oxnard JADU layouts
- A primary bedroom suite at the end of a single-story ranch home, with a new exterior door and a kitchenette added
- Part of an attached two-car garage combined with an adjacent bedroom
- A downstairs bedroom and bath in a newer two-story home in Riverpark, Westport or Seabridge
JADU or garage conversion?
If your garage is detached, converting it into a full ADU usually makes more sense, since it can be larger, fully separate and rented without owner-occupancy questions. If your garage is attached or your lot is tight, a JADU can be the smartest use of space. A builder can show you both options during a free site visit.
Cost
Junior ADUs are typically the least expensive option, often roughly $60,000 to $150,000 depending on how much plumbing and electrical work is needed. See the ADU cost guide for details.
Common questions
How big can a junior ADU be in Oxnard?
A junior ADU can be up to 500 sq ft and must be built entirely within the walls of a single-family home, which can include an attached garage.
Does a JADU need its own bathroom?
No. A junior ADU can have its own bathroom or share one with the main house. It does need its own exterior entrance and at least an efficiency kitchen with a sink, a cooking appliance, counter space and storage.
Do I have to live on the property if I build a JADU?
Owner occupancy can be required for junior ADUs, especially where the JADU shares a bathroom with the main house. If you plan to rent both the main house and the JADU, ask your builder to confirm the current rule before you design it.
Can I have a junior ADU and a detached ADU?
Yes. A single-family lot in Oxnard can generally have one junior ADU inside the house plus one detached ADU in the yard.