Quick Answer: California state law sets a floor and a ceiling for how large a detached accessory dwelling unit can be, but leaves room for individual cities to land anywhere in between. Burbank has generally adopted rules closer to the state’s minimum allowed size, while Los Angeles has generally adopted rules closer to the state’s maximum. That means two otherwise-identical lots — one in each city — can support meaningfully different ADU projects, which matters directly for buyers comparing houses near the shared city line (Toluca Lake, North Hollywood-adjacent streets, and similar areas).
Why would ADU size limits differ between two neighboring cities?
Because state ADU law generally sets outer bounds (a floor a city can’t go below, and a ceiling it can’t exceed) rather than a single mandated number, and leaves the specific figure within that range up to each city’s own ordinance. Burbank and Los Angeles made different choices within that same range, which is why a comparison shopper needs to check both cities’ current rules rather than assuming they match.
How does this actually play out for someone comparing two houses?
If a buyer is weighing a Burbank property against a similarly sized Los Angeles property with ADU potential in mind — a common comparison near Toluca Lake and other shared-border neighborhoods — the maximum buildable unit, and sometimes the allowable height, can differ meaningfully between the two. A floor plan that fits comfortably on one side of the line may need to be redesigned smaller (or larger) to conform on the other side.
Are there Burbank-specific overlays that restrict ADUs further?
Yes. In Burbank’s R-1-H horsekeeping zone (including the Rancho), new ADU construction is limited to converting existing permitted space — an existing garage, an existing permitted guest unit, or square footage inside the main house — and converting barns, stables, tack rooms, or other accessory structures isn’t allowed. In the city’s designated Mountain Fire Zones, R-1 and R-1-H lots are limited to one ADU (capped at a smaller size) or one junior ADU, with brush clearance requirements on top. Anyone evaluating ADU potential on a hillside or Rancho-area property should check these overlays specifically, not just the general citywide rule.
Does the minimum rental term for an ADU differ between the two cities?
It can. State law sets a floor on how short an ADU rental term can be, and cities may adopt a longer minimum in their own code — Burbank’s ADU ordinance, for example, requires ADUs that are rented to be rented for terms longer than 90 days. That directly affects the kind of rental income an ADU can legally generate, so confirm the current minimum term for the specific city and specific ADU approval pathway before counting on ADU rental income in a purchase decision.
How fast does ADU approval move in each city?
Both cities are required to process a complete ADU application within a defined statutory review period without a discretionary hearing. Actual processing time in practice can vary based on staffing and the complexity of the specific plan, and some cities offer a faster “pre-approved plan” track for a limited set of standard designs — worth asking about directly if speed matters for a project timeline.
Related reading: Burbank ADU Rules: Setbacks, Size Limits & Permits and Toluca Lake: Is It Burbank or Los Angeles?.
Frequently Asked Questions
Can I build two ADUs on one single-family lot?
Generally, most single-family zoning caps a lot at one full ADU (plus, in many cases, a separately allowed and smaller junior ADU carved from existing space) — check the current local limit before planning for more.
Does the city require the property owner to live on site to have an ADU?
This restriction has generally been curtailed by state law in most cases — confirm current status, since owner-occupancy requirements for ADUs specifically have shifted several times in recent years.
Do I have to replace a garage’s parking if I convert it into an ADU?
Typically, no — most current ADU rules don’t require replacement parking when an existing garage or covered parking structure is converted, though this is worth a direct confirmation for the specific property.
Is the size difference the only thing that changes at the city line, or are there other differences?
No — height limits, required setbacks, and how a property is billed for utilities can all differ depending on which side of a shared boundary a specific parcel sits on. A property’s exact city of jurisdiction (not just its mailing address) should always be confirmed directly for anything near a boundary.
General information about municipal and state ADU law, not legal or tax advice — this is a fast-moving area of California housing law. Confirm current standards for a specific parcel with the relevant city’s planning department before relying on this for a purchase or construction decision.
About Will Flannigan
Will Flannigan is a California licensed real estate agent (DRE #01951292) and Certified Trust & Probate Specialist (CTPS) with The Nell Team at Equity Union Real Estate. A former attorney, Will brings a background in property management and over a dozen home flips to every transaction, and has been licensed since 2014. A 20+ year resident of Burbank Rancho, Will specializes in Burbank, Altadena, Pasadena, Glendale, and the greater San Gabriel Valley, with fluency in Mandarin serving clients in San Marino and beyond.
Comparing homes on both sides of the Burbank–LA line? The right agent can help you check which city’s rules actually apply to each property before ADU potential gets baked into your price. Let’s talk.
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