Pre-Approved ADU Plans in Los Angeles: City vs. County Programs Explained

Pre-Approved ADU Plans in Los Angeles: City vs. County Programs Explained

"Pre-approved ADU plans" gets thrown around as if it were one program. In Los Angeles it's actually two — a free County catalog and a City of LA program run through LADBS — and which one applies to you depends entirely on your address. Here's how both work, what they actually save you, and where the fine print bites.

The 30-second answer

A pre-approved (or "standard") ADU plan is a design that has already cleared plan check, so the building department only reviews how it sits on your specific lot. If you're in unincorporated LA County, the County publishes free pre-approved standard plans — Plan A, B, and C. If you're in the City of Los Angeles, the LADBS Standard Plan Program permits in roughly 21–30 days instead of the 2–4 months a custom design typically takes. State law AB 1332 requires cities to offer these programs and to approve a standard-plan permit within 30 days.

What "pre-approved" actually means — and what it doesn't

A standard plan is a complete ADU design that an architect or design firm submitted to the building department once, which reviewed it against the building code, Title 24 energy requirements, and structural standards, and stamped it as conforming. Every homeowner who builds that design afterward inherits the approval. The slow part of a custom permit — the plan-check correction loop, where each round of corrections routinely adds four to six weeks — has already happened, on someone else's clock.

What's pre-approved is the building: floor plan, wall sections, framing, energy compliance. What's not — and never can be — is your lot. Placement, setbacks, foundation and soils, drainage, and utility tie-ins are unique to your property, so those sheets still get drawn and still get reviewed. "Pre-approved" removes the design review, not the whole permit.

That distinction matters because it's where over-promising creeps in. A plan can't be "pre-approved for your property" — only for the jurisdiction. Whether a given footprint actually fits inside your setbacks (typically 4 ft side and rear) is a question about your lot, not the program.

Step one: are you in the City of LA or LA County?

This is the fork in the road, and plenty of homeowners get it wrong. "Los Angeles" on your mailing address doesn't settle it.

• City of Los Angeles parcels — including neighborhoods like Van Nuys, Sherman Oaks, and San Pedro — permit through LADBS, so the City's Standard Plan Program is your track.
• Unincorporated LA County parcels permit through the County, so the County's free Plan A, B, and C standard plans are your track — three ready-to-build designs published by the County's Public Works Building and Safety Division.
• Independent cities — Pasadena, Burbank, Glendale, Santa Monica, Long Beach, and dozens more — run their own building departments under California's statewide ADU law. AB 1332 requires them to develop pre-approved standard-plan programs too, so ask your city's planning counter what's in its catalog.

A builder who works across the region will confirm your jurisdiction from the parcel record in minutes. It's the first thing worth checking, because it determines which catalog you're choosing from and who reviews your file.

LA County's free standard plans: Plan A, B, and C

For unincorporated County parcels, the headline is the price: the County's pre-approved standard plans are free to use. You're not paying an architect to design the building or licensing a plan set from a private designer — the County publishes the designs, and your team builds the site-specific package around them.

Free plans don't make the project free, of course. You still pay for the site plan, foundation and soils work, utility connections, permit fees, and the construction itself. But on a project where design fees can otherwise run five figures, starting from a County plan is real money saved before you've broken ground. The tradeoff is the same one every standard plan carries: you take the design as drawn. For the details on what each of the three plans offers and how to choose between them, ask the County's Building and Safety counter for the current Plan A, B, and C spec sheets, or talk to a local builder who has pulled all three.

The City of LA program: LADBS standard plans

The City of Los Angeles runs the larger and better-known program. LADBS maintains a published catalog of approved standard ADU plans — designs submitted by private architects and design firms that have already cleared the citywide plan check. Choose one, and your application skips the full design review; LADBS checks only the site-specific sheets.

The payoff is speed. A standard-plan submittal through ePlanLA turns around in roughly 21–30 days once the package is complete, versus 2–4 months for a typical custom design. That's not a courtesy — AB 1332 requires cities to approve a permit application using a pre-approved plan within 30 days. For the program mechanics step by step, our LADBS Standard Plan Program guide walks the whole path.

Two honest caveats. First, a 15-business-day completeness check (required under SB 543 as of January 1, 2026) runs before any review clock starts — pre-approved is not instant. Second, the speed advantage is fragile: modify the building in any meaningful way — move walls, add a bathroom, stretch the footprint — and the plan loses its pre-approval and goes back through normal plan check.

The speed math: why this is the biggest lever you have

State law (SB 13) already caps ADU plan check at 60 days for a complete, compliant application. In practice, that statutory clock is widely missed on custom builds: UC Berkeley's Terner Center measured LA County at 147 days application-to-permit outside the coastal zone and 260 days inside it. Custom LA permits realistically run 3–6 months once correction rounds are counted.

Construction cost is roughly the same either way — about $250–$400 per square foot in LA — so the savings live in design fees and carrying time, not the build itself. For context, the statewide median ADU runs about $150,000 all-in, and roughly 71% come in under $200,000. One more figure worth knowing: ADUs under 750 sq ft are exempt from impact fees statewide, and most standard plans are drawn with that threshold in mind.

When a pre-approved plan is the wrong tool

Standard plans solve a specific problem — slow, expensive design review on a conventional lot. They don't fit every project:

• Your lot is sloped, narrow, or oddly shaped. A fixed footprint either drops cleanly inside your setbacks or it doesn't. Constrained lots usually need custom design.
• You need a specific layout. Accessibility for an aging parent, a particular kitchen configuration, a second bath — any real modification forfeits the pre-approval.
• You're converting a garage. The pre-approved catalogs are detached new-construction designs. Garage and interior conversions follow the standard permit path — which is still ministerial under state law, just not standard-plan fast.

Budget honestly for the timeline either way: permits are one phase, and the realistic design-to-move-in range for an LA ADU is 8–14 months.

Builders on our directory who work this terrain

Choosing the plan is half the decision; the other half is who executes it. A few vetted, CSLB-licensed builders on our Los Angeles directory whose listed services fit standard-plan work:

• South Land Remodeling (Sherman Oaks — 4.9 stars, 27 reviews) explicitly lists pre-approved ADU plans among its services, alongside architectural design and permit acquisition, serving Los Angeles and LA County.
• NEO Builders ADU (Studio City — 4.9 stars, 137 reviews) handles ADU design and planning plus permitting across LA, the San Fernando Valley, Burbank, Glendale, and Pasadena.
• Olympia Construction by Design (Encino — 4.9 stars, 112 reviews) lists permitting and LADBS compliance as a core service across LA and the Valley.

Every builder we list is pre-screened for an active CSLB license, bond, and insurance, with the license number shown on their profile so you can verify it yourself at cslb.ca.gov. And whoever you hire, remember California's deposit cap: no more than $1,000 or 10% of the contract, whichever is less, up front.

Next steps

Start with jurisdiction, then plan, then builder. If you're in unincorporated LA County, start with the free County Plan A, B, and C standard plans — they're the cheapest starting point in the region. If you're in the City of LA, browse the LADBS catalog with the 21–30 day clock in mind.

Then get a professional read on whether the footprint actually fits your lot. Browse vetted Los Angeles ADU builders and request an intro — you'll get an itemized, fixed-price quote from a CSLB-licensed pro who has already cleared license verification and red-flag screening.