ADU type
Junior ADU (JADU)
A JADU is a small unit (max 500 sqft) created inside the existing footprint of your primary home — usually by walling off a bedroom and adding a kitchenette and exterior entrance. It's the cheapest legal second unit to build, and the only ADU type that requires the owner to live on the property.
What it is
- Maximum 500 sqft, created entirely within the walls of an existing single-family home.
- Must include a kitchenette (sink + small fridge + cooking appliance) and its own exterior entrance.
- May share a bathroom with the main house — own bathroom is optional.
- Owner-occupancy is required: the owner must live in either the JADU or the primary unit.
- Allowed in addition to one regular ADU on the same lot — so a single-family lot can legally host main house + JADU + ADU = 3 units.
Los Angeles · 2026
$65K – $140K all-in
$220 – $380/sqft
Kitchenette plumbing and the new exterior entrance are the main costs.
Bay Area · 2026
$85K – $175K all-in
$280 – $480/sqft
Bay Area JADUs in older homes often need electrical panel upgrades to add the kitchen circuit.
When it fits
- You have a spare bedroom or office near an exterior wall.
- Budget is under $120K and the timeline matters more than rental income.
- You want a family member (parent, adult child) on-property with privacy.
- You plan to stack a JADU and a regular ADU for maximum unit count.
When it doesn't
- You want to leave the property as a pure rental — owner-occupancy disqualifies it.
- You need more than 500 sqft or 1 bedroom.
- The bedroom you'd convert has no exterior wall (interior bedrooms can't easily get the required separate entrance).
Permit pathway
Los Angeles
Ministerial review. Owner-occupancy deed restriction recorded at permit issuance. LADBS typically issues in 30 days.
Bay Area
Ministerial. SF requires a Notice of Special Restrictions on the deed. East Bay cities follow standard ministerial timing.
Realistic timeline
Design + permit: 4–8 weeks. Construction: 6–10 weeks. Plan on 3–5 months total.
FAQ
- Does a JADU need its own water heater?
- No — JADUs can share the main house's water heater, HVAC, and electrical service. That's a big part of why they're so much cheaper than a regular ADU.
- Can I build a JADU and a regular ADU on the same lot?
- Yes. State law explicitly allows both on a single-family lot — one JADU plus one ADU, in addition to the primary residence.
- What happens to the owner-occupancy rule if I sell the house?
- The deed restriction transfers with the property. The new owner must live in either the JADU or the main house.
- Does a JADU need a full kitchen?
- No — a 'kitchenette' meets the requirement: a sink, a small fridge, and a hot plate or microwave. A 220V range is not required.