What are the City of San Fernando's ADU rules, and is my address even in it?

Is my "San Fernando" address actually in the City of San Fernando?

Not necessarily. The San Fernando mailing address and the 91340 ZIP code are used on both sides of the city line. The Los Angeles Department of Building and Safety, which only permits inside the City of Los Angeles, issued 28 ADU permits in ZIP 91340 in 2025 and 21 more through September 2026 ¹⁶, on Sylmar, Mission Hills and Pacoima lots.

The city was incorporated in 1911 and its water utility serves about 2.42 square miles and 23,946 people ¹⁰. Three lookups settle which side you are on:

1. ZIMAS, the City of Los Angeles zoning map, returns zoning and permit history only for City of Los Angeles parcels ¹⁴. If ZIMAS finds your address, you are in Los Angeles; read our Sylmar or Pacoima guides instead.
2. The county's maps. Los Angeles County Public Works keeps the legal city boundaries in its City Boundaries layer ¹⁵, and the county's Z-NET map masks every incorporated city out in white and tells you to contact that city directly ¹³. White at your address means a city, and here that is either Los Angeles or San Fernando.
3. Your water bill. The City of San Fernando runs its own water department, drawing from wells in the Sylmar basin ¹⁰. If LADWP bills you for water, you are in Los Angeles.

The city's Community Development Department at City Hall, 117 Macneil Street, is the office that would issue your permit.

What does the City of San Fernando allow on a single-family lot?

As of May 2025, on a lot with one house: one ADU inside the existing house or an existing accessory structure, plus one detached new backyard house (or an attached addition in its place), plus one junior ADU inside the house ³. There is no minimum lot size ¹.

• Size: a detached ADU may be up to 850 sq ft with one bedroom or 1,200 sq ft with two or more bedrooms; an attached ADU has the same caps and may not exceed 50 percent of the main house's gross floor area ².
• Height: 18 feet for a detached unit, plus 2 feet so the roof pitch can match the house; 25 feet attached; one story above a garage ². The state's base height for a detached ADU is 16 feet, so the city gives you two extra feet ¹⁹.
• Setbacks: 4 feet from side and rear lot lines, and the front setback of your zone ⁴. A conversion keeps its existing setbacks if the Los Angeles Fire Department finds them sufficient for fire safety ⁵.
• Parking: none for the ADU, and no replacement parking for a converted garage ⁴.
• Owner occupancy: not required for an ADU; required for a junior ADU, by deed restriction ⁴⁷.

The code also writes in the state's "statewide exemption" unit: whatever else the city's standards say, they cannot block an ADU of up to 800 sq ft, 18 feet tall if detached, with 4-foot side and rear setbacks ¹. And it says plainly that if anything in the chapter conflicts with state law, state law governs ¹. See also our guides on setbacks, owner occupancy and JADUs versus ADUs.

What does San Fernando require that Los Angeles does not?

Design rules. The San Fernando code adds a short list of architectural requirements that will show up on your plans ⁵:

• Exterior materials and colors of walls, roof, windows and doors must match the main house, and the roof slope must match the house's dominant slope.
• An ADU above a garage may not have its entrance facing a neighbor's property.
• A pedestrian walkway to the sidewalk at least 4 feet wide.
• Landscape screening between the ADU and the side and rear lot lines.
• In a garage conversion, the garage door comes out and is replaced with windows or entry doors.

Sprinklers work as they do statewide: required in the ADU only if the main house requires them, and building an ADU does not force sprinklers into the existing house ⁸. See our fire sprinkler guide.

The state's protection runs in your favor: a city may not impose standards on a single-family ADU beyond those the state allows ¹⁸, and the city's own code says state law wins any conflict ¹.

How does the permit process work in the City of San Fernando?

It is a building permit, not a hearing. You file a complete building permit application with the city's Building Safety Division, and the division must approve or deny it within 60 days of accepting a complete application when there is already a house on the lot, without discretionary review or a hearing ⁶.

Before the permit is issued, the code names three payments ⁶:

• An address assignment request and fee to the Public Works Department.
• City impact fees, only if the ADU adds 750 sq ft or more, and then in proportion to the main house's floor area. State law exempts ADUs of 750 sq ft or less of interior livable space from impact fees entirely ¹⁸. Water and sewer connection fees are not impact fees and are charged separately.
• School impact fees if the ADU is 500 sq ft or more; see our school fee guide.

Utilities are the part that is genuinely different. Water comes from the City of San Fernando's own wells, not LADWP, so the LADWP meter costs in our other guides do not apply; ask the city's Public Works Department for its connection charges ¹⁰. Sewage goes to Los Angeles: the Hyperion plant serves San Fernando along with Beverly Hills, Culver City, El Segundo, Santa Monica and West Hollywood ¹¹. Fire is Los Angeles too: the LAFD provides fire and emergency medical services to the city under a contract the LA City Council amended in July 2022 ¹². See our fire access guide.

Are City of San Fernando homeowners actually building ADUs?

Yes. The city reports its permits to the state each year in its Housing Element Annual Progress Report. ADU units issued building permits by the City of San Fernando ¹⁷:

• 2022: 51
• 2023: 46
• 2024: 88
• 2025: 58

In 2024, ADUs were 88 of the 96 homes of any kind the city permitted, so the backyard house is nearly the only new housing being built inside the city limits ¹⁷.

The Los Angeles side runs on LADBS permits: ZIP 91340 had 33 ADU permits in 2024 and 28 in 2025, while the neighboring LA ZIPs did far more in 2025 (Pacoima 91331: 156, Sylmar 91342: 119, Mission Hills 91345: 47) ¹⁶. LADBS counts never include a City of San Fernando lot, so the city is missing from our Valley permit count by ZIP.

What should I check first for a City of San Fernando address?

In this order:

1. Which city. ZIMAS, the county boundary map, and who bills your water ¹⁴¹⁵¹⁰.
2. Your zone. 4-foot side and rear setbacks, but the front setback and the other standards of your zone still apply ⁴⁵.
3. The unit. Up to 1,200 sq ft with two or more bedrooms and 18 feet plus the roof-pitch allowance, or the 800 sq ft exemption unit if a zone rule gets in the way ²¹.
4. The design rules. Matching materials, colors and roof slope, a 4-foot walkway, landscape screening, no garage door left on a conversion ⁵.
5. The money. Address fee, impact fees only at 750 sq ft and up, school fees at 500 sq ft and up, and the city's own water and sewer connection charges ⁶¹⁸.
6. Fire. LAFD is the fire authority here, so the same access and sprinkler questions apply as in Los Angeles ¹²⁸.

This is the kind of thing a lot check settles in one pass, before you pay for plans.

Quick answers

Sources

1. San Fernando Municipal Code Sec. 106-520 (Ord. No. 1732, May 5, 2025), introduction and subsections (1)-(2): state law governs conflicts, no minimum lot size, statewide exemption ADU (Municode text as reproduced by GoCodebook), City of San Fernando. Facts checked 2026-10-13
2. San Fernando Municipal Code Sec. 106-520(3) and (6)a: maximum unit size and height, City of San Fernando. Facts checked 2026-10-13
3. San Fernando Municipal Code Sec. 106-520(6)a: ADUs allowed on a single-family lot, City of San Fernando. Facts checked 2026-10-13
4. San Fernando Municipal Code Sec. 106-520(9), (11) and (12)a: parking, owner occupancy, rentals, setbacks, City of San Fernando. Facts checked 2026-10-13
5. San Fernando Municipal Code Sec. 106-520(12)b and (14): fire-safety setbacks judged by LAFD; architectural, entrance, walkway, landscape and garage-conversion requirements, City of San Fernando. Facts checked 2026-10-13
6. San Fernando Municipal Code Sec. 106-520(15): application process, 60-day decision, address fee, impact fees, school fees, City of San Fernando. Facts checked 2026-10-13
7. San Fernando Municipal Code Sec. 106-520(13): junior accessory dwelling units, City of San Fernando. Facts checked 2026-10-13
8. San Fernando Municipal Code Sec. 106-520(14)h-i: fire sprinklers and solar, City of San Fernando. Facts checked 2026-10-13
9. San Fernando, California (geography), Wikipedia (secondary source). Facts checked 2026-10-13
10. 2025 Annual Water Quality Report, Where Does My Water Come From?, City of San Fernando Public Works Department. Facts checked 2026-10-13
11. LA to pay $20.8 million for discharging untreated wastewater into Santa Monica Bay (Aug. 21, 2024), ABC7 Los Angeles. Facts checked 2026-10-13
12. Council File 13-1644, Council Action of July 29, 2022: Second Amendment to Contract No. C-124744 (LAFD fire and EMS services to the City of San Fernando), Los Angeles City Clerk. Facts checked 2026-10-13
13. Z-NET, Find your zoning, Los Angeles County Department of Regional Planning. Facts checked 2026-10-13
14. Zoning Search (ZIMAS), Los Angeles City Planning. Facts checked 2026-10-13
15. City Boundaries layer (PW_Jurisdiction_Locator, layer 0), Los Angeles County Department of Public Works GIS. Facts checked 2026-10-13
16. Building Permits Issued from 2020 to Present (N), dataset pi9x-tg5x, ZIPs 91340, 91331, 91342 and 91345, LADBS via City of Los Angeles Open Data (Greenlight query). Facts checked 2026-10-13
17. Housing Element Annual Progress Report (APR) Data by Jurisdiction and Year, Table A2, JURIS_NAME = SAN FERNANDO, California HCD via data.ca.gov (Greenlight query). Facts checked 2026-10-13
18. Accessory Dwelling Unit Handbook (March 2026): impact fees under 750 sq ft; no standards beyond Gov. Code 66314 on single-family ADUs, California Department of Housing and Community Development (HCD). Facts checked 2026-10-13
19. Accessory Dwelling Unit Handbook (March 2026), Summary of Recent Changes: Detached ADU Height Allowances, California Department of Housing and Community Development (HCD). Facts checked 2026-10-13

Greenlight is not a contractor, architect or engineer, and this is not legal advice. Rules change; every fact here shows the date we last checked it.