Quick answer: An ADU or JADU costs $1,200–$380,000 in Los Angeles, with JADUs using existing interior space and ADUs requiring new construction. APLA Construction (CA Lic #1136359) provides free estimates across Greater Los Angeles.
The California ADU law expansion since 2020 has created two distinct paths for adding a rental unit to your Los Angeles property: the full Accessory Dwelling Unit (ADU) and the Junior Accessory Dwelling Unit (JADU). They are not interchangeable — they have different size limits, ownership requirements, construction approaches, costs, and rental income potential. This guide explains exactly what each one is, when to choose one over the other, and what each option actually costs in Los Angeles in 2026. APLA Construction (CA Lic #1136359) builds both ADUs and JADUs throughout greater Los Angeles.
An Accessory Dwelling Unit (ADU) is a fully independent residential unit on a property that already has (or is adding) a primary residence. An ADU has its own entrance, its own kitchen or kitchenette, its own bathroom, and its own heating and cooling system. It is a complete, independent dwelling.
A Junior Accessory Dwelling Unit (JADU) is a smaller, simpler independent unit created within the existing footprint of the primary residence. A JADU is carved out of the existing home — it cannot be new construction added outside the existing walls.
| Feature | ADU | JADU |
|---|---|---|
| Maximum size | 1,200 sq ft | 500 sq ft |
| Location | Existing or new structure | Within existing home only |
| Full kitchen required | Yes | No (efficiency OK) |
| Own bathroom required | Yes | No (can share) |
| Owner-occupancy required | No | Only if the bathroom is shared |
| Can be sold separately | Only where the city has adopted an AB 1033 condo ordinance (not yet the City of LA) | No |
| Construction cost (LA 2026) | $85,000–$380,000+ | $45,000–$95,000 |
| Rental income (1-bed) | $1,800–$3,800/month | $1,200–$2,200/month |
| LADBS permit timeline | 4–8 weeks (ministerial) | 3–5 weeks (ministerial) |
| Item | Typical Cost |
| Garage conversion ADU (400–600 sq ft) | $85,000–$155,000 |
| New detached ADU (400–600 sq ft) | $155,000–$265,000 |
| New detached ADU (800–1,200 sq ft) | $255,000–$420,000 |
| Attached ADU addition | $165,000–$320,000 |
| Item | Typical Cost |
| Converting a bedroom + adjacent space within existing home | $45,000–$75,000 |
| Converting an attached garage to JADU | $55,000–$95,000 |
| Converting basement space to JADU | $65,000–$110,000 (egress window addition may be required) |
Rental income varies significantly by neighborhood:
JADUs are smaller, simpler units — typically rent for 60–75% of ADU rates for equivalent neighborhoods. A 400 sq ft JADU in Culver City rents for $1,600–$2,200/month vs. $2,500–$3,800 for a full garage conversion ADU.
Size and independence. A JADU is limited to 500 sq ft and must be carved out of the existing home — it cannot be a new structure. A JADU that shares a bathroom with the main house also requires owner-occupancy; an ADU never does. An ADU can be up to 1,200 sq ft, can be a separate new structure (or garage conversion), and does not require the owner to live on-site.
For maximum rental income: ADU. For minimum construction cost: JADU. For an investor who will not live on the property: an ADU, or a JADU with its own bathroom (a JADU that shares a bathroom requires owner-occupancy). For a homeowner who wants to add a small in-law suite as cheaply as possible while continuing to live in the main home: JADU may be the right choice.
Yes. California law (AB 2221) and the City of Los Angeles ADU ordinance allow one ADU plus one JADU on a single-family residential property. This combination can maximize rental income; if the JADU shares a bathroom with the main house, the owner must live in the JADU or the house. APLA has built ADU + JADU combinations in Encino, Culver City, and the San Fernando Valley.
JADU permits in LADBS are ministerially approved — meaning no discretionary review, no public hearing. Plan check takes 3–5 weeks. APLA manages all LADBS submissions for JADU projects.
Yes. APLA (CA Lic #1136359) builds ADUs and JADUs throughout greater Los Angeles — garage conversions, new detached ADUs, attached additions, and JADU conversions within existing homes. Call (818) 818-4419 for a free feasibility assessment.
Call: (818) 818-4419
Email: info@aplaconstruction.com
CA General Contractor License #1136359 — verify on CSLB
Serving all of greater Los Angeles including Sherman Oaks, Encino, Culver City, Santa Monica, Pasadena, Glendale, Burbank, and the South Bay.
ADU Construction Los Angeles | ADU Contractor Los Angeles | ADU Cost Los Angeles 2026