An accessory dwelling unit, or ADU, is a secondary home on the same lot as a main home.
That re-confirm framing runs through this whole guide. Where a provision is sourced, it is stated as sourced and to be re-confirmed.
What an ADU remodel actually involves in San Fernando
An ADU remodel can mean finishing or updating an existing ADU, converting a garage into an ADU, or building a new detached ADU. Those are different permits and different scopes, and confusing them is the most common planning mistake. A habitable conversion — turning a garage into a room that is not a separate dwelling — is not the same as an ADU conversion, and the two should not be planned as if their requirements were identical.
Start by establishing which kind of unit you are planning, on which lot, under which current city text. A parcel check with the City of San Fernando Community Development Department, Building and Safety Division, at City Hall, 117 Macneil Street, is the route for that question inside the city.
Sourced San Fernando ADU provisions, to re-confirm
The provisions below are the sourced San Fernando provisions found in Municipal Code Chapter 106, Article IV, Division 1, sections 106-520 through 106-523. Re-confirm the current text before publishing or relying on any of them, because their currency after the 2025 Chapter 106 rewrite is itself a verification item.
- No minimum lot size is stated in the sourced provisions.
- Detached ADU size limits of 850 and 1,200 square feet, depending on the case described in the provisions.
- Height of 18 feet plus 2 feet for pitch, and 25 feet for an attached ADU, as stated in the sourced provisions.
- Side and rear setbacks of 4 feet.
- Parking and replacement parking are not required under the sourced provisions.
- A junior ADU, or JADU, of up to 500 square feet within the existing residence.
- A process described as a 15-business-day completeness check plus a 60-day decision, under the state-law ministerial clock.
- Impact fees only at 750 square feet or more, on a proportional basis, and school fees at 500 square feet or more. No fee amount is given here.
Behind those city provisions sits a state floor: ministerial review without a discretionary hearing, and a rule that an 800-square-foot ADU with 4-foot setbacks cannot be blocked on those grounds, with no owner-occupancy requirement for a standard ADU. State law and city text both need to be checked in their current form for a particular lot.
Garage-door and solar rules for conversions
Two conversion-specific rules from the sourced provisions are easy to miss. On an ADU conversion of a garage, the garage door must be removed or replaced. And solar is required only for new detached ADUs, not for conversions. Planning a conversion as if either rule ran the other way creates rework, so both belong in the written scope from the start.
How much does an ADU cost, in published market ranges
Published Los Angeles-area market ranges from October 2026, not VisionCrest prices, put a detached ADU at $180,000 to $450,000 across publishers, with custom detached work cited higher by one publisher. A basic non-ADU office conversion, around $25,000 in one publisher guide, is not a habitable ADU and must not be quoted as one.
Call to talk through your project and book an in-home visit.
Common mistakes on ADU remodels in San Fernando
- Planning a habitable conversion and an ADU conversion as if they were the same permit and scope.
- Relying on an ADU provision without re-confirming the current city text after the 2025 rewrite.
- Budgeting a garage-conversion ADU from a low outlier range, or an office-conversion figure, instead of the full publisher disagreement.
- Leaving the garage-door rule or the conversion solar rule out of the written scope.
When to call a professional
Call before work starts if the unit type, the lot rules, or the permit route is unclear for your address. ADU planning questions are parcel questions, and a phone conversation can establish which provisions to re-confirm and which permit route applies before design work is priced.
Sources: San Fernando Municipal Code Ch. 106 ADU provisions cited in this article, to be re-confirmed before work.
Get help with Remodeling in San Fernando
Call VisionCrest Remodeling at +1 (818) 412-6345, Monday to Sunday, 5:00 a.m. to 9:00 p.m., to talk through unit type, lot questions, and the permit route for your address.
Related pages: Kitchen Remodeling, Bathroom Remodeling, Whole-Home Remodeling, Downtown San Fernando, How to convert your garage into an ADU in San Fernando, Home, Services, Locations, and Contact. VisionCrest Remodeling: 924 Newton St, San Fernando, CA 91340, +1 (818) 412-6345, Monday–Sunday, 5:00 a.m.–9:00 p.m..