ADU design
ADU plans: pre-approved, stock and custom drawings
By the HyreADU research desk. Last checked .
The short answer
ADU plans come in three kinds: plans a city or county has pre-approved, stock plans you license from a designer, and custom plans drawn for your lot.
In California every local agency had to set up a preapproval program by January 1, 2025, and a detached ADU on a current-cycle preapproved plan gets a 30-day decision. Every kind still needs a site plan for your lot.
| Agency (own page) | What it offers | As listed on the agency page |
|---|---|---|
| City of Los Angeles (LADBS) | Standard Plan Program | YOU-ADU, a city-owned 455 sq ft 1-bedroom plan, free; designer plans listed for purchase from their owners |
| City of San José | Preapproved ADUs | 7 approved plans from 5 vendors, counted September 5, 2026 |
| City of Oakland | Pre-approved building plans | City PDFs for a studio, 1-bedroom and 2-bedroom |
| City of Fresno | ADU and Small Homes Program | 5 free plans, studio to 3-bedroom, 3 elevations |
| County of Santa Barbara | Pre-approved ADU building plans | 4 plan sets in several styles (unincorporated county) |
| City of San Francisco | Pre-approved ADU plans | None posted at retrieval |
Pre-approved plans
Pre-approved plans have already passed building code review for a set code cycle. Under Gov. Code § 65852.27 (AB 1332), a complete application for a detached ADU that uses one gets a ministerial decision within 30 days.
Your city still reviews the site: setbacks, utilities, the foundation for your soil, and zoning. Plans approved under an earlier code cycle can expire; Fremont, for example, said its 2022-cycle plans became invalid on January 1, 2026.
Stock plans from designers
Stock plans are designs a designer or company licenses to you. They are not approved for your city until your city approves them, unless they are listed in its program. You will still need a site plan, energy compliance forms and often structural calculations. See ADU plans for sale for what a purchase usually includes.
Custom plans
Custom plans are drawn for your lot by a designer or architect. They fit slopes, odd setbacks and the look of your house, and suit attached ADUs and conversions, which the 30-day clock does not cover. Compare the routes on pre-approved vs custom plans.
A mistake to avoid
The mistake to avoid is buying a plan before checking that it fits your lot. A footprint that ignores your setbacks, the sewer line or a tree will be redrawn, and the redraw can take it out of a preapproval program. Start with the pre-approved ADU plan finder and the size envelope calculator.
What to do next: check your lot with the ADU feasibility checker, read the questions to ask an ADU builder, then tell us about your project. Matching is not live yet, so we reply with information, not a quote.
Get ADU optionsQuestions
Where do I find my city’s pre-approved ADU plans?
On the planning or building department site, often under “ADU”. Our research page links 35 California programs.
Are pre-approved ADU plans free?
Some city-owned plans are free, such as Los Angeles’s YOU-ADU and Fresno’s set. Designer-owned plans are bought from the designer.
Can I use a plan from another city?
Some cities accept other agencies’ plans; San Diego, for example, lists three. Ask yours.
Do pre-approved plans include the foundation?
They include a design, but your lot’s soil and site may require changes reviewed by the city.
Sources
- Gov. Code § 65852.27 (preapproved ADU plan programs, AB 1332). Checked September 5, 2026.
- LADBS, ADU Standard Plan Program. Checked September 5, 2026.
- City of San José, Preapproved ADUs. Checked September 5, 2026.
- City of Oakland, Apply for ADUs with Pre-Approved Plans. Checked September 5, 2026.
- City of Fresno, ADU and Small Homes Program. Checked September 5, 2026.
- County of Santa Barbara, Pre-Approved ADU Building Plans. Checked September 5, 2026.
- San Francisco, get your detached ADU plan pre-approved. Checked September 5, 2026.
- City of Fremont, Preapproved ADUs. Checked September 5, 2026.
HyreADU is a publisher. It does not design, permit or build ADUs, has no partner builders, and gives no legal, tax, lending or engineering advice.
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