LA Pre-Approves 20 ADU Designs. Picking One Is Still on You.

WELCOMEPROJECTS's The Breadbox, one of the pre-approved designs in LA's Standard Plan catalog. ArchDaily.

You want a backyard ADU, you would rather not pay an architect to draw one from a blank page, and you have heard that Los Angeles keeps a shelf of designs the city has already blessed. That shelf is real: the LADBS Standard Plan Program pre-approves roughly 20 ADU designs from 14 architecture firms, and building from one can shrink plan check from the usual four to six weeks down to as little as a single day.

The short version:

• Los Angeles runs three tiers of pre-approved ADU plans: the free 455-square-foot YOU-ADU, about 20 marquee designs from named firms, and a separate, longer private-designer catalog.
• A standard plan pre-clears the building and its structural engineering, which is why the city reviews it fast. It does not pre-clear your lot.
• The site-specific sheets, foundation, soils where the slope demands one, utility connections, and the plot plan, are still yours to draw and pay for, and they are where the calendar actually goes.

If you are a first-time ADU client, the pitch sounds like a shortcut around the hardest part of the job. It is a shortcut around a real part of the job, just not the part you think. Here is how the shelf is actually organized, and how to shortlist it without burning a week.

Tier one: the free plan, and its 455 square feet

Start at the bottom of the price ladder. The city gives away the YOU-ADU, a 455-square-foot one-bedroom drawn by Lehrer Architects with the Bureau of Engineering, at no cost for the design itself. We walked through it in detail when the free YOU-ADU plan came up earlier this summer. It is a genuinely good plan. It is also 455 square feet, so a dining table and a second closet are now competing for the same wall.

The free design is the right call when your budget is tight, your lot is flat and rectangular, and you can live inside a compact one-bedroom footprint. If any of those three is not true, you are shopping the next two tiers.

Tier two: the 20 designs the city commissioned

This is the tier people mean when they say "the LA catalog." Administered by the Los Angeles Department of Building and Safety, it pairs the city with name-brand firms: SO IL's Pebble House, with its flower-shaped footprint built for cross ventilation; work from LA-Mas; WELCOMEPROJECTS's Breadbox; a design from Jennifer Bonner. These are architecture you would recognize from a magazine, pre-reviewed so the structural and code work is already done.

The catch on this tier is that the design is not free the way YOU-ADU is. You license or buy the plan set from the firm, and the marquee firms price accordingly. What the city gives you is the fast review, not the drawings. Shortlist here by three filters, in order: does the footprint fit your lot with four-foot side and rear setbacks, does the square footage match how you will actually use the unit, and is it a one-story or two-story design your neighborhood and your budget can carry.

Tier three: the private-designer catalog

The tier almost nobody talks about is the largest. Any qualified designer can submit a plan and have LADBS pre-approve it, which means the full catalog runs well past the 20 headline designs. This is where prefab and design-build firms park the plans they sell every week. The whole private-designer catalog is being reissued to comply with the building-code changes that took effect January 1, 2026, so confirm any plan you like is on the current code cycle before you commit.

One more fork, and it is an address question, not a design question: the city designs run through LADBS, but if your parcel sits in unincorporated Los Angeles County, you use a different counter and a different free catalog through LA County Regional Planning. City counter versus county counter is not a formality; it decides which shelf you are even allowed to shop. Pull your address first.

Where people get stuck

Here is the sentence the program does not print in its own headline. A standard plan is a building, drawn once and cleared for anywhere. Your lot is specific. So the pre-approved set covers the structure, but you still have to produce the sheets that tie that structure to your dirt: the plot plan, the foundation detail for your soil, a soils report if you are on a slope, and the utility connections. That work carries its own fees and its own review, and on a tight or hilly parcel it is the long pole in the timeline.

Our read: the catalog's real value is not the free or cheap drawing, it is the pre-cleared engineering and the one-day review that comes with it. Treat the design as the settled part and the site work as the open budget, and you will price the project honestly. Do it the other way around and the "free plan" headline will mislead you by tens of thousands. Price the lot first.

The cross-street check. Los Angeles is unusually rich here, and the contrast with our other markets is the point. San Francisco runs a pre-approved catalog too, but it is thin: a handful of 25-foot-lot designs, a review fee near $1,472, and a list of slope, seismic, and flood zones that rule many lots out before you pick a plan, as we covered when SF's pre-approved plans landed. New York City only opened its first plan library this year, the 11-design ADU for You set, when the city began accepting ADU applications in the five boroughs. Against a thin SF shelf and a brand-new NYC one, LA offers a free plan, roughly 20 commissioned designs, a deep private catalog, and a second free catalog for the county. The breadth is the advantage; the site work is the leveler.

The cost ledger, honestly

Line it up before you fall for the word "free." The YOU-ADU design costs nothing; a marquee or private plan costs a design or licensing fee to the firm; and every path, free or paid, still owes the city its permit and plan-check fees plus the site-specific engineering. The design is the cheap line. The lot is the expensive one. Shortlist the plan in an afternoon, then spend your real diligence on the parcel.

When you are ready to compare designs and line up the site work against real quotes, A-du's build marketplace puts pre-approved plans and vetted builders on the same page.

The private-designer catalog is still being reissued for the 2026 code, so the shelf you shop this fall will look different from the one that launched in 2021, and that is the version worth watching.

Elsewhere on the ADU beat

• Los Angeles council members are weighing whether homeowners can sell an ADU separately from the main house, a cheaper path to ownership, LAist.
• San Francisco already passed the law letting owners sell new in-law units as condos, Mission Local.
• Seattle eased its accessory-dwelling restrictions just ahead of the state deadline, The Urbanist.