What happens if you skip the permit (and you needed one)
- Stop-work orders issued by LA County or San Fernando code enforcement can halt construction and impose $1,000–$5,000 in civil penalties, plus double permit fees if you file retroactively.
- Title-transfer disclosures: unpermitted ADUs must be disclosed to buyers under California Real Estate Code 1102.6c, tanking resale value and exposing you to fraud liability ($10,000–$100,000+ in litigation).
- Lender and insurance rejection: FHA and conventional loans will not fund or refinance a property with an unpermitted ADU; homeowners insurance may deny claims related to the unit.
- Los Angeles County tax reassessment can add $15,000–$50,000 to your property tax basis once discovered, with back-taxes and penalties accruing.
San Fernando ADU permits—the key details
California Government Code Section 65852.2 (amended by AB 881 and SB 9) is the controlling law in San Fernando. The statute requires cities with populations under 25,000 to approve at least one ADU per single-family lot and to allow two ADUs on certain parcels—one detached ADU and one junior ADU (an interior conversion without a separate kitchen). San Fernando cannot impose minimum lot sizes, floor-area ratios, open-space requirements, or parking mandates that exceed the state standard for ADUs. The state law also eliminates owner-occupancy requirements: you do not have to live in the main house or the ADU. This is critical. Many homeowners assume San Fernando has a 'you must occupy it' rule; the state preempts that entirely. The city can enforce setbacks (typically 5 feet from side/rear property lines for detached ADUs) and egress standards (IRC R310: operable windows or doors for emergency escape), but those rules are spelled out in Government Code 65852.2, not San Fernando's local code.
Setback and lot-size rules for San Fernando follow the state default unless the city has a locally-adopted ADU ordinance that is MORE permissive. Most small LA County cities do not; San Fernando is no exception. This means a detached ADU must be set back at least 5 feet from side and rear property lines (not 25 feet or more, as some older city codes once required). If your lot is smaller than 1,250 square feet or your main house is on a hillside or in a fire-hazard overlay zone, the state allows up to a 4-foot setback or waiver in certain cases. Verify setbacks with the Building Department, but you have a strong statutory baseline. The rule exists to prevent fire spread and maintain neighborhood character while still encouraging housing. If your lot is 40 feet wide and 80 feet deep (3,200 sq ft total), a detached ADU of ~500 sq ft is almost certain to fit; if your lot is 30x60 feet (1,800 sq ft) in a dense part of town, you may need a garage conversion or junior ADU instead.
Parking and utility requirements in San Fernando are mostly waived for ADUs under state law. Government Code 65852.2 eliminates off-street parking for ADUs within half a mile of public transit, and San Fernando qualifies (Metro bus routes run through the city). Even if you're not near transit, the state allows you to provide one tandem or compact space (or zero if infeasible). You do not need a separate parking lot. However, utilities are different: if the ADU is detached, you must show separate meter connections for water and power (or demonstrate that the main meter can serve both units with a split). If the ADU is a garage conversion or junior ADU, you may sub-meter or demonstrate shared service. The Building Department will require a utility plan showing either separate service or approved sub-metering. Electrical work (including sub-meter installation) must be done by a licensed electrician; plumbing must be licensed as well. This is non-negotiable under Title 24 (California Code of Regulations).
Egress and emergency escape windows are mandatory under IRC R310 and California Building Code. Every habitable room in an ADU (bedroom, living room, family room) must have an operable window or door that allows emergency exit without tools. For a bedroom, the window must be at least 5.7 square feet of net opening area, with sill height no more than 44 inches above the floor. If your garage conversion has a bedroom in the back and the only exit is through the front garage door, you need a secondary egress window. This requirement frequently triggers rejections in plan review. Plan your bedroom layouts with egress in mind; sketch the windows on your floor plan and note dimensions. If a room is small and can't fit a code-compliant window, it cannot be a bedroom—it's a den or office.
The permit process in San Fernando follows the state 60-day shot clock (AB 671). Once you submit a complete application (ADU plans, lot line verification, utility diagram, environmental review waiver if applicable), the Building Department has 60 days to issue a permit or issue a notice of incomplete application. If incomplete, you have 15 days to respond; the clock restarts. Most ADU applications in San Fernando take 4-8 weeks if complete and clear. Inspections happen in this order: foundation (if detached), framing, rough electrical/plumbing/HVAC, insulation and drywall, final building, and utility sign-off. Each inspection must pass before the next stage. Plan for 1-2 week intervals between inspections if you're coordinating contractors. Owner-builder status is allowed under California Business & Professions Code Section 7044 for owner-occupied projects, but you must pull all permits yourself and hire licensed trades for electrical, plumbing, gas, and solar work.
Three San Fernando accessory dwelling unit (adu) scenarios
California's ADU laws override San Fernando's local zoning — here's why that matters
Until 2018, many California cities—including small ones like San Fernando—used local zoning to block ADUs outright. A homeowner could not legally build a second unit on a single-family lot, no matter how large the parcel. This changed when Assembly Bill 2299 (effective January 1, 2018) required cities to approve at least one ADU per single-family lot under specific conditions. That law was strengthened by AB 881 (2020), which eliminated owner-occupancy requirements and reduced setbacks statewide. Then SB 9 (2021) allowed two units on certain single-family lots (one detached ADU plus one junior ADU), and AB 671 (2021) imposed the 60-day permit shot clock. San Fernando, with a population under 25,000, cannot opt out of these laws and cannot impose restrictions more stringent than state code.
What this means in practice: if you file an ADU application in San Fernando that complies with Government Code 65852.2, the city must issue the permit. The Building Department cannot reject it based on local zoning restrictions, neighborhood compatibility, or 'protecting the character of the area.' The city can enforce setbacks, egress, utilities, and fire safety—but only to the extent allowed by state law. If San Fernando's local code says 'ADUs only allowed on lots over 1 acre' or 'ADU owner must live in main house,' those rules are void. You reference the state statute, not the city code. This is a rare situation where state law preempts local zoning entirely, and it's a huge advantage for homeowners in small cities.
However, this does not mean zero local review. San Fernando still charges permit and plan-review fees, coordinates with the Fire Marshal and LA County on hillside or fire-hazard projects, and applies design review if you're in the historic district. The 60-day shot clock applies to the building permit, not the design review; if historic district review is required, that happens in parallel. The city is a gatekeeper for safety and design, not zoning. Knowing this distinction saves you months of frustration: don't negotiate the zoning—file under state law and focus on getting inspections right.
Utilities, separate metering, and cost: why a detached ADU's electrical setup matters
One of the most common deal-breakers in ADU projects is the utility situation. Many homeowners assume they can wire the ADU from the existing main electrical panel or split the water meter. That's not how it works in San Fernando. For a detached ADU, the Building Department and the utility companies (Southern California Edison for power, local water agency) require evidence of separate service or approved sub-metering. This is not a suggestion—it's a code requirement under Title 24 (California Energy Code) and the California Plumbing Code. Why? Because utilities need to bill each unit separately, and because code assumes each unit is independent. If there's a fire or electrical fault in the ADU, the main house shouldn't be at risk.
For electrical, a detached ADU typically needs a separate 50-amp or 100-amp service (depending on size and appliances) fed from a new meter can at the property line or on the main building. This is not a simple extension cord; it's a full subpanel with breakers, disconnect, and grounding. The cost is $1,500–$3,000 for the meter can, service line, and subpanel. A licensed electrician must do this work; you cannot owner-build it. Water service is simpler: a new water line from the main supply with its own shutoff valve and (ideally) its own meter. Cost: $800–$1,500 depending on distance and whether the line is buried or above-ground. If the lot is large and the ADU is 50+ feet from the main house, trenching costs climb. For sewer, if the main house is on a municipal sewer line, the ADU taps into the same main line (no separate 'sewer meter'—it's a single system), but the Building Department must verify that the main line has adequate capacity. A septic system cannot be legally split between two units in San Fernando (two units = two separate systems required).
One money-saving option: sub-metering. Instead of a full separate electrical service, you can install a sub-meter (a revenue-grade meter installed downstream of the main panel) that measures only the ADU's consumption. This is cheaper ($800–$1,200 installed) but requires a formal lease or utility agreement stating who pays the ADU's share. Lenders and some buyers are skeptical of sub-metered units because they think the owner is cutting corners. A true separate service is safer and more marketable; plan for $2,000–$3,000 in electrical upgrade costs for a detached ADU. Ask the Building Department's plan reviewer for a pre-application meeting (free, 30 minutes) to discuss your specific utility plan before investing in detailed drawings.
City of San Fernando, 117 Maclay Avenue, San Fernando, CA 91340
Phone: (818) 898-1200 (main line; ask for Building Department) | https://www.ci.san-fernando.ca.us/ (navigate to 'Building Services' or search 'San Fernando permit portal')
Monday–Friday, 8:00 AM – 5:00 PM (verify holiday closures locally)
Common questions
Does the owner of the ADU have to live in the main house or the ADU?
No. California Government Code 65852.2 eliminates owner-occupancy requirements for ADUs. You can own the property, live elsewhere, and rent out both the main house and the ADU. San Fernando cannot impose an owner-occupancy rule. However, if you sell the property, you must disclose the ADU's existence and its rental status to the buyer under California Real Estate Code 1102.6c.
Can I build an ADU if my lot is smaller than 5,000 square feet?
Yes. State law sets no minimum lot size for ADUs, and San Fernando cannot impose one. However, your lot must be large enough to accommodate setbacks (typically 5 feet from rear/side lines for a detached ADU per Government Code 65852.2) and meet egress requirements (operable emergency windows). A 3,000 sq ft lot (say, 40x75 feet) can usually fit a 400-600 sq ft detached ADU or a garage conversion. Smaller lots (under 2,000 sq ft) may be too tight for detached ADUs but can accommodate junior ADUs or garage conversions.
What is the difference between an ADU and a junior ADU?
An ADU is a separate unit with its own kitchen (including stove, oven, and refrigerator), bathroom, and living space—essentially a small apartment. A junior ADU is a unit carved out of the existing main house (or an attached structure like a garage) that has a kitchen, bathroom, and separate entrance, but is smaller (typically 500 sq ft or less) and may share some utilities or mechanical systems with the main house. San Fernando allows one detached ADU per lot and one junior ADU per lot (Government Code 65852.2(e))—you can have both on the same parcel.
Do I need off-street parking for my ADU?
No. Government Code 65852.2 waives off-street parking requirements for ADUs in San Fernando because the city is within half a mile of public transit (Metro bus routes). You are not required to provide a dedicated parking space for the ADU. Parking is optional if infeasible on your lot. This is a major cost-saver compared to older zoning codes that mandated 1-2 spaces per unit.
Can I use owner-builder status to pull permits and save money on my ADU?
Partially. California Business & Professions Code Section 7044 allows owner-builders to pull permits for owner-occupied properties, including ADUs. However, you must hire licensed contractors for electrical work (including sub-panels and service upgrades), plumbing, gas, and solar installations. You can do framing, drywall, painting, and finish work yourself. For an ADU, licensing requirements are rigid; expect to hire a general contractor or electrician for at least 30-40% of the work. Owner-builder saves fees ($200–$400) but not labor costs.
How long does it take to get an ADU permit in San Fernando?
The city has a 60-day shot clock (AB 671) from the date of a complete application to issue or deny the permit. In practice, most straightforward ADU applications (detached or garage conversion on a flat lot, no historic overlay) take 4-6 weeks. Hillside or fire-hazard projects take 8-12 weeks due to additional review (Fire Marshal, geotechnical). Add 8-12 weeks for construction and inspections, so plan 4-6 months total from permit to occupancy.
If I sell my house, do I have to disclose the ADU to the buyer?
Yes, absolutely. California Real Estate Code Section 1102.6c requires sellers to disclose any unpermitted or permitted ADU on the property, its rental status, and any restrictions (e.g., owner-occupancy, if applicable). The ADU is a material fact that affects property value and financing. Failure to disclose is fraud and can result in rescission of the sale or civil liability ($10,000–$100,000+).
What happens if my ADU doesn't meet setback or egress requirements?
The Building Department will issue a 'notice of incomplete application' and request revised plans. Egress is mandatory; every bedroom must have an operable window or door (IRC R310). If your ADU layout cannot accommodate egress, you cannot have a bedroom in that room—it must be a den or office. Setbacks are based on state law (5 feet minimum, 4 feet in some fire-hazard zones) and property lines; if your ADU is too close, redesign the footprint or the location. Plan review exists specifically to catch these issues before construction.
Do I need environmental clearance or a California Environmental Quality Act (CEQA) review for my ADU?
ADUs are generally exempt from CEQA under Government Code 66411.7 if they are consistent with the general plan and the lot is urban (already served by water/sewer). San Fernando is urban, so most ADU projects qualify for a CEQA exemption and require no environmental review. The Building Department will note 'CEQA Exempt' on your permit. Projects on agricultural land or environmentally sensitive areas may need review; ask the Planning Department during pre-application.
What does a pre-application meeting cost, and how do I schedule one?
Pre-application meetings (informal plan reviews) are typically free and last 15-30 minutes. You bring a sketch or plot plan, describe your project, and the plan reviewer tells you what documents and standards you'll need. This costs nothing and saves time later. Call the Building Department at (818) 898-1200 and ask for 'ADU pre-application' or 'over-the-counter review.' Some cities charge $50–$100; San Fernando's fee schedule should be on their website.