Los Angeles has some of the most ADU-friendly rules in the country, but the details still trip people up. Before you plan an accessory dwelling unit, it helps to know the sizes, setbacks, and permits that actually apply to your lot in 2026.
Here is a plain-English guide to the rules that matter most.
How many ADUs can you build?
Under current California and Los Angeles rules, most single-family lots can add both:
- One ADU (attached, detached, or a garage conversion), and
- One junior ADU (JADU) of up to 500 square feet, created within the existing home.
Multifamily properties can often add even more, based on the number of existing units. Your specific lot determines the exact count.
Size limits
ADU size is capped by state and local rules, but the limits are generous:
| ADU type | Maximum size |
|---|---|
| Studio / 1 bedroom | Up to 850 sq ft |
| 2+ bedrooms | Up to 1,000 sq ft (or more in some cases) |
| Junior ADU (JADU) | Up to 500 sq ft |
Detached ADUs of at least 800 square feet are generally allowed regardless of other lot restrictions, which is why 800 square feet is such a common target.
Setbacks
Setbacks are the required distance between your ADU and the property lines. The key rules:
- Four-foot setbacks from the side and rear property lines for a new detached ADU.
- No new setback required when converting an existing structure like a garage, as long as it is not expanded.
- Front setbacks follow the underlying zoning of your lot.
Parking rules
This surprises many owners: in most cases you are not required to add parking for an ADU, especially if the property is within half a mile of public transit. And when you convert a garage into an ADU, you generally do not have to replace the lost parking.
Permits you will need
An ADU is a permitted construction project. Expect to pull:
- A building permit from LADBS
- Electrical, plumbing, and mechanical permits as part of the build
- Approved plans prepared by a designer or architect
Los Angeles also offers pre-approved ADU plans, a set of standard designs that move through permitting faster because the city has already vetted them.
Owner-occupancy and rental rules
For standard ADUs, there is currently no owner-occupancy requirement, which means you can rent out both the main house and the ADU. Junior ADUs do require the owner to live on the property. Short-term rentals (under 30 days) are restricted, so most ADUs are rented as long-term housing.
Frequently asked questions
Can I build an ADU and a JADU on the same lot?
Yes. Most single-family lots in Los Angeles can add one ADU plus one junior ADU, giving you two additional units alongside the main house.
Do I need to add parking for my ADU?
Usually not, particularly near transit or when converting an existing garage. This is one of the biggest advantages of building an ADU in LA.
How close to the property line can I build?
A new detached ADU generally needs a four-foot setback from the side and rear lines. Converting an existing structure typically keeps its current position.
Want to know what your lot allows?
The rules are friendly, but every lot is different. JJP Construction can review your property, confirm exactly what you can build, and handle the plans and permits from start to finish.
