Short Answer
Yes, alwaysA Building Permit is required to create any ADU or junior ADU in San Diego, with no exemptions, according to Development Services Information Bulletin 400. ADUs can be attached or detached and up to 1,200 square feet, JADUs are 150 to 500 square feet inside the house or an attached garage, and applications using a preapproved plan get a 30-day review.
Source: City of San Diego Information Bulletin 400: Accessory Dwelling Unit/Junior Accessory Dwelling Unit (linked under Sources below)
San Diego ADU Permits at a Glance
- ADU permits, last 12 months
- 478
- Median application to issue
- 213 days
- Slowest quarter took at least
- 385 days
- New detached ADUs
- 183
Of the 7 cities we track for ADUs, San Diego ranks 6 of 7 by median wait. The median declared job value on these permits was $109,841.
Who Can Apply and Do the Work
Applications are filed digitally through the Development Services Application Portal under Building Construction. Depending on how many units the ADUs create, the City issues either a Combination Building Permit or a Building Permit. The owner does not have to live on site for an ADU, but must live in one of the units when there is a JADU that shares sanitation with the house.
What You Need Before the Permit Is Issued
- Find the lot's zone in the Zoning and Parcel Information Portal (ZAPP). A single dwelling unit zone allows one attached or detached ADU, one converted ADU and one JADU.
- Size: at least 150 square feet; attached and detached ADUs up to 1,200 square feet; conversions of existing space are not capped at 1,200.
- Setbacks: ADUs over 16 feet tall next to residential neighbors keep at least 4 feet from interior side and rear lines, and in a Very High Fire Hazard Severity Zone every ADU does.
- Parking: none outside the Coastal Overlay Zone, and a garage converted or demolished for the ADU does not have to be replaced.
- A Coastal Development Permit in the Coastal Overlay Zone for ADUs not contained in the existing house.
- Plans: site plan, floor and roof plans, elevations, structural plans and calculations, and Title 24 energy calculations, plus forms DS-3032, DS-16 and DS-560.
- For a JADU, a recorded Junior Unit Agreement before the permit is issued.
What Else to Know in San Diego
A new detached ADU must have solar panels under the California Energy Code, on the ADU or the main house; conversions and JADUs do not. ADUs pay school fees, the General Plan Maintenance Fee and Development Impact Fees, and must be rented for more than 30 days.
San Diego ADU Permit Costs
San Diego does not publish a flat ADU permit fee; plan check and permit fees are calculated from the project valuation when you apply, so we don't quote one. For scale, the median declared value of ADU work on recent permits was $109,841.
What San Diego's ADU Permit Data Shows
| Type of ADU | Permits | Share |
|---|---|---|
| Conversion of a garage, basement or other existing space | 170 | 36% |
| New detached ADU | 183 | 38% |
| Attached ADU | 43 | 9% |
| Junior ADU | 48 | 10% |
| Not specified in the description | 34 | 7% |
ADU Permits Issued per Month
Types are classified from each permit's description. Approvals in the City's development permits feed whose scope mentions an ADU, JADU or accessory dwelling unit. Data from City of San Diego Development Permits (Set 2), October 30, 2025 to October 30, 2026.
Where ADUs Are Being Permitted
| ZIP code | Permits (12 mo) |
|---|---|
| 92115 | 18 |
| 92102 | 10 |
| 92117 | 9 |
| 92126 | 8 |
| 92110 | 7 |
| 92105 | 7 |
Recent ADU Permits
| Issued | Work as described by the city |
|---|---|
| 2026-10-29 | For the proposed to add to an existing (above garage) guest quarters and converting that space to an ADU by ad |
| 2026-10-27 | For proposed detached 1-story ADU to an existing 2-story SDU. Work to include 1 bedroom and 1 bath. RS-1-14, P |
| 2026-10-27 | For proposed (N) 2-story structure with ADU on each floor along with stairs, covered patio & entry landing. BC |
| 2026-10-26 | For the proposed installation of a new detached manufactured ADU on a SDU lot. Work to include living room, ki |
| 2026-10-26 | For a proposed new ADU addition detached from the Single-Family Residence. RS-1-7, VHFSZ |
| 2026-10-22 | For addition and remodel of the existing one-story SDU. Work includes the attached ADU. BC 4333 |
How to Get an ADU Permit in San Diego
- Confirm what your lot allows. Zoning, existing unit count, hillside, fire and historic status decide which ADU types and how many you can add.
- Choose the program and plans. Decide between the State program and the Local program; they cannot be combined.
- Complete the prerequisites listed above before you file.
- File the building permit through PermitSF, over the counter or for in-house review.
- Build, pass inspections and get final sign-off before anyone moves in.
Frequently Asked Questions
Do I need a permit to build an ADU in San Diego?
A Building Permit is required to create any ADU or junior ADU in San Diego, with no exemptions, according to Development Services Information Bulletin 400. ADUs can be attached or detached and up to 1,200 square feet, JADUs are 150 to 500 square feet inside the house or an attached garage, and applications using a preapproved plan get a 30-day review.
How long does an ADU permit take in San Diego?
For the 478 ADU permits issued between October 30, 2025 and October 30, 2026 with both dates published, the median time from application to issue was 213 days, and a quarter took 385 days or longer, according to the city's open data.
How many ADU permits does San Diego issue?
478 in the 12 months to October 30, 2026. About 36% converted existing space such as a garage, 38% were new detached units, 9% were attached and 10% were junior ADUs, based on the permit descriptions.
Do I need parking for an ADU in San Diego?
Not outside the Coastal Overlay Zone. Inside it, one space is required only in the Beach Impact Area outside a transit priority area, with exceptions such as ADUs of 500 square feet or less.
How big can an ADU be in San Diego?
Between 150 and 1,200 square feet for attached and detached ADUs. Converting existing space is not capped at 1,200 square feet, and a JADU is 150 to 500 square feet.
Related Permit Guides
- San Diego Building Permits
- ADU Permit Requirements: What Homeowners Need to Know
- Los Angeles ADU Permit Requirements
- San Francisco ADU Permit Requirements
- Chicago ADU Permit Requirements
- Austin ADU Permit Requirements
- Seattle ADU Permit Requirements
- New York ADU Permit Requirements
Sources
Official sources checked on . Rules change; confirm with the department before you start work.