Guides / ADUs · Updated
ADU floor plans you can use for free
From the County of San Diego's plan sets and the state housing department's ADU Handbook, checked November 2026.
Short answer
The County of San Diego gives away six ADU plans, from a 600 sq ft one-bedroom to 1,200 sq ft with three bedrooms. The smallest needs a back corner about 32'-7" by 25'-0" once you add the state's 4 ft setbacks. The City of San Diego accepts the plans too, and reviews permits that use them in 30 days.
The six plans and their blueprints
| Plan | Size | Bedrooms, baths | Outside footprint | Height | The County's blueprints |
|---|---|---|---|---|---|
| Plan F | 600 sq ft | 1 bedroom, 1 bath | 28'-7" × 21'-0" | 14'-0" | PDF, full size, CAD |
| Plan E | 800 sq ft | 1 bedroom, 1 bath | 42'-2" × 25'-0" (L-shaped) | 12'-6" | PDF, full size, CAD |
| Plan D | 1,000 sq ft | 1 bedroom, 1.5 baths | 31'-6" × 31'-9" | 15'-0" | PDF, full size, CAD |
| Plan A | 1,200 sq ft | 3 bedrooms, 1 bath | 40'-0" × 30'-0" | 14'-6" | PDF, full size, CAD |
| Plan B | 1,200 sq ft | 2 bedrooms, 1 bath | 54'-0" × 32'-0" (L-shaped) | 13'-0" | PDF, full size, CAD |
| Plan C | 1,200 sq ft | 2 bedrooms, 2 baths | 34'-3" × 35'-0" | 15'-6" | PDF, full size, CAD |
Footprints are the outside walls, read off each plan's floor plan sheet; each multiplies out to the plan's stated area. Heights run from finished grade to the top of the roof, off the front elevation; every plan is under the state's 16 ft. Plan D's half bath is a powder room. The links open the County's own files.
How much of your lot each one needs
State law caps side and rear setbacks for an ADU at 4 ft. Add that to the footprint and you get the clear ground each plan needs:
| Plan | In a back corner | Narrowest lot it fits across | On your lot |
|---|---|---|---|
| Plan F | 32'-7" × 25'-0" | 29'-0" wide, reaching 32'-7" in from the back line | Place it |
| Plan E | 46'-2" × 29'-0" | 33'-0" wide, reaching 46'-2" in from the back line | Place it |
| Plan D | 35'-6" × 35'-9" | 39'-6" wide, reaching 35'-9" in from the back line | Place it |
| Plan A | 44'-0" × 34'-0" | 38'-0" wide, reaching 44'-0" in from the back line | Place it |
| Plan B | 58'-0" × 36'-0" | 40'-0" wide, reaching 58'-0" in from the back line | Place it |
| Plan C | 38'-3" × 39'-0" | 42'-3" wide, reaching 39'-0" in from the back line | Place it |
A back corner means 4 ft from the side line and 4 ft from the rear line. The narrowest lot is the plan turned so its short side faces the street, with 4 ft to both side lines. L-shaped plans use their overall size, so the real need is a little less. Your city also sets how far the ADU must stand from the house, and the front setback, so check its ADU page.
To see it on your own lot, use the measuring map: find your address, turn on the property lines, set the setback to 4 ft, and set the plan down. It warns you when the plan crosses the setback line.
Where you can use them
The County says the plans "may be used as an Accessory Dwelling Unit (ADU) or a Single Family Dwelling (SFD) in the unincorporated areas of the County of San Diego." The City of San Diego's companion and junior units page accepts the County's set, along with Chula Vista's and Encinitas's, and reviews applications that use one in 30 days. In any other city, ask the building department before you start.
Each set is "approximately 85% complete": it comes with a blank plot plan and the stormwater forms, and the County's Dwelling Unit Checklist lists everything else you fill in. The sheets also carry a release: using them, you agree to release the County from claims and to check every detail yourself.
What California law guarantees
- An ADU of at least 800 sq ft with 4 ft side and rear setbacks, whatever the local lot rules (Gov. Code § 66321(b)(3)).
- A detached ADU 16 ft tall, or 18 ft within a half-mile walk of major transit (§ 66321(b)(4)).
- No impact fees at 750 sq ft or less, which takes in Plan F.
The rest, from parking to how many units a lot gets, is in ADU rules in California. To price one of these plans, with the City of San Diego's permit fees, use the ADU cost calculator.