Guide
Pre-approved ADU plans in San Diego County: who offers them and do they save time?
The short answer
Most of the county's 19 permit authorities now run a program, and at least 11 offered or accepted plans you could build from when we checked (the table below lists each one). State law gives a 30-day decision on a detached ADU that uses a plan the agency pre-approved in the current code cycle, against 60 days for other ADUs on a lot with a home. The time you save is in design and plan review. You still supply a site plan, energy calculations and whatever your lot triggers.
What state law asks of every city and the County
Since January 1, 2025, every city and county in California has had to run a program that pre-approves ADU plans. Anyone may submit a plan. The agency reviews it against the same standards as any other ADU and may charge the same fees, then posts each plan it pre-approves on its website with the applicant's contact details. Posting a plan is not an endorsement of the applicant. An agency may also add plans it drew itself or plans another California agency has pre-approved.
The reward is a shorter clock. For a detached ADU, the agency must approve or deny a complete application within 30 days when it uses a plan the agency pre-approved in the current building code cycle, or one identical to a plan used in a detached ADU application it approved during that cycle. Other ADU applications on a lot that already has a home get 60 days, and the agency has 15 business days to tell you whether your application is complete.
The code cycle matters. California's 2025 building codes took effect on January 1, 2026, and the 30-day rule speaks of plans pre-approved within the current cycle. Carlsbad's program page says its plans are being redrawn to the 2025 codes, and the City of San Diego says a plan must meet the codes in force when you apply. Check the code year printed on the set before you rely on it.
Who offers plans, authority by authority
The table comes from each authority's own ADU or plan page. Programs change often, so confirm with the authority before you license a plan or pay for drawings.
| Permit authority | What we found |
|---|---|
| City of San Diego | Accepts the County's standard plans, Chula Vista's standard plans and Encinitas's permit-ready plans, with a 30-day review. Designers can apply to have their own plans pre-approved through the City's master plan process. You ask the plan's provider about any license cost. |
| Unincorporated County | Six plans usable as an ADU, from 600 to 1,200 square feet, posted as PDF and CAD files. The County calls them about 85 percent complete; its checklist lists what you fill in for your lot. |
| Carlsbad | Four single-story detached plans in three styles under its Permit Ready program, offline while the City updates them to the 2025 codes. They were expected back by summer 2026 and were still listed as unavailable when we checked on October 19, 2026. |
| Chula Vista | Twelve City Standard plans in six sizes from 498 to 1,199 square feet, each also drawn flipped, plus plans from private designers as the City accepts them. The City reviews these in 14 business days instead of 21. You contract with the plan's designer to use it. |
| Coronado | A program with plans in three architectural styles, which the City expects to open for use by fall 2026. A draft went to the Planning Commission on July 14, 2026. |
| Del Mar | Three sample floor plans, from 446 to 955 square feet, for public use. They are floor plans only, not construction drawings, so they give you a head start rather than a pre-approved permit set. |
| El Cajon | Not found. The City's planning page lists no plan program, and its ADU pages refused automated reading, so we could not confirm one. |
| Encinitas | Eight permit-ready plans from two local architects, from a 224-square-foot studio to a 1,199-square-foot three-bedroom unit, and since January 1, 2025 a program that lets private parties have their own plans pre-approved. Any change to a plan sends it to standard review. |
| Escondido | Four plans for new detached ADUs, from 484 to 1,000 square feet, with a guidebook in English and Spanish. The City says the plans are not specific to any site and still go through the standard ADU permit. |
| Imperial Beach | One 600-square-foot plan, with checklist guidance. |
| La Mesa | Five plans from 224 to 1,199 square feet; you email Planning for the construction set. The City also points to the County's plans. |
| Lemon Grove | One posted plan set, a one-story two-bedroom detached ADU drawn to the 2025 codes. No changes are allowed. |
| National City | Not found on the City's ADU page. |
| Oceanside | Not found. The City's ADU page says its ADU ordinance is being certified with the state and points to state law in the meantime. |
| Poway | A policy in effect since March 4, 2025 that lets architects submit plans and promises a 30-day review to homeowners who use them. No plans had been submitted when the policy was written, and we found no posted list. |
| San Marcos | City plan sets for one-story detached ADUs, mostly complete, with a decision within 30 days of a complete application. Altered plans are not accepted. |
| Santee | Accepts the County's, Chula Vista's and Encinitas's plans, and describes the County's as free to residents. |
| Solana Beach | A program that takes plans from designers for detached ADUs up to 800 square feet and 16 feet tall. The City's planning page showed no list of pre-approved plans. |
| Vista | Four plans from 499 to 1,149 square feet, for lots with an existing single-family home. The City waives plan check fees when you use one; permit and inspection fees still apply. |
Carlsbad's building page still describes the plans as available, but its program page, the one that runs the plans, says they are offline. Check that page or ask Carlsbad Planning before you plan around them.
Do they save time?
They can, in two places. Most of the design is done before you start, and the review is shorter. Chula Vista reviews its standard plans in 14 business days rather than 21, and the City of San Diego gives applications that use the plans it accepts a 30-day review.
Carlsbad estimates its plans spare a homeowner three to six months of planning and design. That is the City's own figure, not a measured result.
None of the pages we read publishes data on how much a pre-approved plan shortens a whole project, from first sketch to final inspection. A plan does not shorten grading, utility connections or the build itself.
What a pre-approved plan leaves to you
- A site plan. The programs ask you to show where the ADU sits on your lot, against the property lines and the other buildings.
- Energy documents for your site. La Mesa, Vista and Chula Vista each ask for Title 24 energy calculations specific to the project.
- Soils and grading. Vista wants a soils report unless the footings reach at least 24 inches into competent soil, La Mesa wants one over 500 square feet, Poway wants one that checks the plan's assumed bearing strength, and some lots need grading review first.
- The reviews your lot triggers. Lemon Grove warns that the departments that look at topography and other site conditions still review and are likely to comment, and Solana Beach notes that slopes, habitat or fire mitigation can call for more studies even with a pre-approved design.
- No edits. Changing a room layout or moving a window usually sends the project back to standard review.
- The right to use the plan. The City of San Diego tells you to ask the provider what a license costs, Chula Vista requires a contract with the designer, and Poway lets the architect charge a fee. The County posts its plans for download.
- Fees. Plan review and permit fees still apply in most places. Vista waives plan check fees for its plans, and Encinitas says it waives plan review and inspection fees on ADU permits apart from state fees and a few others.
What changes the answer
The cases where a pre-approved plan helps less, or not at all.
Your authority's own list
Each authority decides which plans it accepts. The City of San Diego and Santee take the County's, Chula Vista's and Encinitas's plans, and La Mesa points to the County's; the others we read list only their own. A plan from a neighboring city may need standard review where you build.
An attached ADU, a conversion or a junior ADU
The 30-day clock in state law covers detached ADUs, and the programs that describe their plans offer detached units. An attached unit or a conversion goes through standard review.
A two-story ADU
The programs that state a height or story count offer one-story plans: Carlsbad and San Marcos say single-story, and Solana Beach caps its plans at 16 feet. If you want two stories or an ADU over a garage, check whether your authority's plans include one; if not, it means a design of your own.
The Coastal Zone
Near the coast you still need a coastal development permit alongside the building permit: in the City of San Diego's Coastal Overlay Zone for most new ADUs, and in Carlsbad and Encinitas as well.
Fire hazard zones
Poway asks for a landscaping plan approved by its fire department and wildfire-resistant construction when a pre-approved ADU goes in its very high fire hazard zone.
A homeowners association
Deed and HOA rules that effectively prohibit or unreasonably restrict an ADU on a single-family lot are void, though reasonable restrictions can stand.
Utilities, septic and power
Vista requires County Health clearance first on a septic lot, and SDG&E asks for the ADU's own address from the city or County before you apply for service.
Next steps
Find your authority, see what your lot allows, then price the ADU.