ADU vs. JADU: What's the Difference?

Odysseas Lamprianidis
Aug 11
3 min read

Ever felt like LA's building codes are written in another language?

You're not alone.

Whether you're planning a backyard rental, thinking about a SB9 lot split in LA, or just wondering what kind of permits you need to build a second unit—knowing the difference between an ADU and a JADU could save you thousands of dollars and months of delays.

What Is an ADU?

An Accessory Dwelling Unit (ADU) is a self-contained residential unit located on the same lot as a primary residence. Think: backyard bungalow, above-garage studio, or a converted garage.

It includes:

Full kitchen
Full bathroom
Sleeping and living area
Its own entrance

Size: Up to 1,200 sq ft (and at least 800 sq ft is always allowed under state law, no matter your zoning or lot size).

Detached or Attached?

It can be either.

Detached ADUs often get more size and flexibility, but attached ADUs are a great way to build within your existing home footprint.

Permits:

Requires full permits through LADBS.

And here’s the Major Advantage:

If it meets objective standards, it must be approved within 60 days under ministerial review.

What Is a JADU?

A Junior Accessory Dwelling Unit (JADU) is a smaller, more limited version of an ADU—but still a powerful tool for LA homeowners.

Max size: 500 sq ft
Must be within the existing or proposed space of a single-family home
Can share a bathroom with the main house
Must have a separate entrance and an efficiency kitchen
Requires owner-occupancy (either the SFD or the JADU must be lived in by the owner)
Cannot be sold separately (deed restriction required)

How to Choose One Over the Other?

Feature	ADU	JADU
Max Size	Up to 1,200 sqft	Up to 500 sqft
Location	Attached or Detached	Must be attached to the main home
Bathrooms	At least 1	Can share with the main home
Kitchen	Full Kitchen	Efficiency Kitchen
Separate Sale Allowed?	Usually No*	No
Owner-Occupancy	Yes*	Yes
Parking	Usually No*	No

*Under certain local codes, answers may vary. For specific details on your property, reach out to our team to be quickly and easily assisted.

Quick Reference for Builders & Homeowners:

You can build both an ADU and a JADU on the same single-family lot in LA
ADUs are eligible for Density Bonus programs, especially under SB9 lot split rules
LADBS requires no minimum lot size, and you can build up to 800 sq ft by-right (even if it busts your RFA or FAR limits)
Fire sprinklers not required if the main house doesn’t have them
If you're in a Very High Fire Hazard Severity Zone (VHFHSZ) and Hillside Area, additional rules apply (like road width and parking)