The answer to the question is “Yes!” You can build more than one accessory unit on your property in San Fernando. However, the number of units allowed depends on whether your property is a single-family home or a multifamily residence.
As of
January 2026, San Fernando follows the updated California state laws (such as SB 1211 and SB 543) which have expanded the allowances for number of accessory dwelling units on a lot.
1. If you have a Single-Family Home
You are permitted to have a total of
two accessory units on a single-family lot:
- One Detached or Attached ADU: A full independent living unit up to 1,200 square feet.
- One Junior ADU (JADU): A unit of no more than 500 square feet created within the walls of the primary house (e.g., a converted bedroom or garage attached to the house).
- Note on "Triplex" Potential: Between the main house, the ADU, and the JADU, you can effectively have three separate living spaces on one lot.
2. If you have a Multifamily Property (Duplex, Apartments, etc.)
The rules for multifamily lots were significantly expanded by
SB 1211 (which became effective in 2025/2026):
- Detached ADUs: You can build up to
eight detached ADUs, provided the number of ADUs does not exceed the number of existing primary units on the lot. (e.g., if you have a 4-unit apartment, you can add 4 detached ADUs).
- Conversion ADUs: You can convert non-habitable spaces within the existing building (basements, attics, storage rooms) into ADUs. You are allowed at least one, or up to
25% of the existing unit count.
- Combined: Under 2026 law, you can now combine both detached and conversion ADUs on the same multifamily lot.
San Fernando Specific Standards (2026)
The Maximum Size
is 1,200 sq. ft. for detached ADUs. Attached ADUs are capped at 50% of the main house size (but regardless, you are always allowed at least 800 sq. ft.).
Setbacks from Property Lines is 4 feet from side and rear property lines.
Height
Maximum height is generally 16–18 feet, but can go up to
25 feet if the lot is near transit or to match the roof pitch of the main house.
Parking
No parking is required if you are within
1/2 mile of public transit (which applies to most of the City of San Fernando due to its density and the number of bus lines running thought the city).
Important Update: Pre-Approved Plans
San Fernando has been working to provide
pre-approved ADU plans to residents. Using these "off-the-shelf" designs can bypass much of the architectural review process and significantly lower your permit fees and wait times.
Reach out to us at San Fernando Valley ADU Construction Contractors for more information on this or other ADU questions in Rosemead and all of the San Gabriel Valley. Our phone number is 626-900-0952 (click to call).
