The short version
The City of San Diego allows ADUs in zones where homes are allowed. A permit is required for every ADU and junior ADU (JADU); there are no exemptions. Most lots outside the Coastal Overlay Zone need no parking for an ADU.
| Item | Rule |
|---|---|
| Maximum size | 1,200 sq ft (not applied to conversions of existing space) |
| Minimum size | 150 sq ft |
| Parking | None required outside the Coastal Overlay Zone |
| Owner must live on site (ADU) | No |
| Minimum rental term | 31 consecutive days |
| JADU size | 150 to 500 sq ft |
Source: https://www.sandiego.gov/development-services/forms-publications/information-bulletins/400. Checked 2026-10-22.
What counts as an ADU or a JADU
An ADU is an attached or detached home with its own living, sleeping, eating, cooking and sanitation space. It is 1,200 sq ft or less and sits on a lot with a house or other homes.
A JADU is smaller: 150 to 500 sq ft, built inside an existing or planned single home or its attached garage. It needs a kitchen or efficiency kitchen. It can share a bathroom with the main home.
Source: https://www.sandiego.gov/development-services/forms-publications/information-bulletins/400. Checked 2026-10-22.
How many ADUs you can build
On a lot in a single-dwelling zone, the city lists up to four units in total: the main home, one ADU (attached or detached), one ADU converted from existing space, and one JADU.
In multi-dwelling zones the city allows ADUs converted from non-livable space in an existing multi-unit building (storage rooms, attics, basements, garages), up to 25% of the existing units and at least one, plus up to eight detached ADUs on a lot with an existing multi-unit building, not more than the number of existing units. A proposed multi-unit building can have up to two detached ADUs. JADUs are not allowed in multi-dwelling zones unless a single previously conforming home exists.
Source: https://www.sandiego.gov/development-services/forms-publications/information-bulletins/400. Checked 2026-10-22.
Size and floor area
An ADU is 150 to 1,200 sq ft. Converting an existing accessory building or part of the home is not held to the 1,200 sq ft cap, and you may add up to 150 sq ft just for an entry or exit.
ADU floor area normally counts toward the zone's floor area ratio (FAR). The city carves out one exception: one ADU up to 800 sq ft can be built even if it takes the lot over the FAR limit. A JADU does not count toward the lot's floor area.
Source: https://www.sandiego.gov/development-services/forms-publications/information-bulletins/400. Checked 2026-10-22.
Setbacks and height
| Case | Rule |
|---|---|
| Converting an existing building | Keep the existing setbacks |
| Rebuilding in the same place and size | Keep the original setbacks |
| Front yard | Follow the zone; one ADU of 800 sq ft or less may encroach into it |
| Street side yard | The zone setback or 4 ft, whichever is less |
| Interior side and rear yard | Can reach the property line, unless building code (fire separation, openings, height, area) says otherwise |
| ADU taller than 16 ft next to residential property | 4 ft interior side and rear, or the zone setback if that is less |
| Very High Fire Hazard Severity Zone | 4 ft interior side and rear at any height; the fire official may ask for more |
Height: on lots where only a single home is allowed, a detached ADU can be at most two stories. All ADUs must stay within the zone's overall height limit. Exterior stairs, decks and balconies follow the base zone setback.
Source: https://www.sandiego.gov/development-services/forms-publications/information-bulletins/400. Checked 2026-10-22.
Parking
No parking is required for an ADU outside the Coastal Overlay Zone. Inside it, one space is required only in the Beach Impact Area of the Parking Impact Overlay Zone and outside a transit priority area, with exceptions (an ADU of 500 sq ft or less, an attached ADU, a historic district, a residential permit parking district, or a car share within one block).
Turning a garage, carport or covered parking into an ADU does not require replacement parking, with the same Coastal exception. Uncovered spaces do not need replacing either.
Source: https://www.sandiego.gov/development-services/forms-publications/information-bulletins/400. Checked 2026-10-22.
Renting, selling, sprinklers and solar
The owner does not have to live on the property for an ADU. An ADU cannot be leased for less than 31 consecutive days. A JADU must be rented for longer than 30 days, and the owner must live on site unless the JADU has its own bathroom (or the owner is a government agency, land trust or qualified housing group).
An ADU needs fire sprinklers if the main home has them, and a new detached ADU cannot force sprinklers into the existing home. A newly built detached ADU must provide solar panels under the state energy code; ADUs inside existing space or added onto homes do not.
New or existing ADUs may be subdivided into condominiums and sold separately from the main home under the city's rules (municipal code section 141.0302(f)). The bulletin lists conditions, including a 30-day public listing for buyers who will live in the unit, a Davis-Stirling condominium plan, and lienholder consent. ADUs that got San Diego Housing Commission financing, or that are rent-restricted to very low, low or moderate income households, cannot be sold off while the restriction lasts. A JADU cannot be sold separately.
Source: https://www.sandiego.gov/development-services/forms-publications/information-bulletins/400. Checked 2026-10-22.
The ADU bonus program
The city's ADU Home Density Bonus Program lets you add bonus (market-rate) ADUs when you build deed-restricted affordable ADUs. Inside Sustainable Development Areas you get one bonus ADU per qualifying affordable ADU. Outside them the limit is one bonus ADU and one affordable ADU.
Lot-size caps apply (lot area excludes environmentally sensitive lands): 4 ADUs and JADUs in total on 8,000 sq ft or less, 5 on 8,001 to 10,000, and 6 on more than 10,000. The city's own table lists "10,000 or greater" for the top band, so check with the city if your lot is exactly 10,000. Affordable and bonus ADUs need sprinklers, a recorded agreement with the San Diego Housing Commission, a community enhancement fee, tree planting, and one parking space each outside transit priority areas. Some single-home zones are excluded, and very high fire zone lots need two evacuation routes. Read the bulletin and the municipal code before counting on it.
Source: https://www.sandiego.gov/development-services/forms-publications/information-bulletins/400. Checked 2026-10-22.
Permit steps
Here is the path the bulletin describes.
- Find your zone in the city's Zoning and Parcel Information Portal (ZAPP).
- Prepare plans: site plan, floor and roof plans, elevations and sections, structural plans and calculations, and Title 24 energy calculations. Forms DS-3032, DS-16 and DS-560 go with them.
- Apply online in the Development Services portal. Choose "Building Construction" under Building Applications.
- Pay fees online, by check, or at the Development Services Center.
- In the Coastal Overlay Zone, a Coastal Development Permit is needed for an ADU unless it sits completely inside the existing primary structure with no added habitable area and no converted non-habitable space. A JADU does not categorically need one.
Source: https://www.sandiego.gov/development-services/forms-publications/information-bulletins/400. Checked 2026-10-22.
Fees
The bulletin lists the fee types but not dollar amounts for ADUs. It says ADUs and JADUs pay school fees and the General Plan Maintenance Fee, ADUs pay development impact fees, and projects with more than one ADU pay regional transportation congestion fees. Bonus program projects add a community enhancement fee. ADUs are not exempt from the city's inclusionary housing rules: a project with an ADU that results in 10 or more total homes (5 or more in the Coastal Overlay Zone) is subject to them.
School fees: the city's school-fee bulletin lists an exemption for one new detached ADU or JADU when the assessable space created is under 500 sq ft.
The bulletin points to Information Bulletin 501 and the city fee page for amounts. No fee waiver program is described there.
Source: https://www.sandiego.gov/development-services/forms-publications/information-bulletins/400; https://www.sandiego.gov/development-services/forms-publications/information-bulletins/146; https://www.sandiego.gov/development-services/forms-publications/information-bulletins/501. Checked 2026-10-22.
Preapproved plans and review time
Under state law (AB 1332) you can apply with preapproved ADU plans. The city says those applications get a 30-day review and must still meet the municipal code. To use one, contact the plan's provider for the license cost. The city lists preapproved plans on its ADU page, and designers can apply to have their plans preapproved under Information Bulletin 114a.
The bulletin gives no standard review time for custom plans. Ask Development Services.
Source: https://www.sandiego.gov/development-services/forms-publications/information-bulletins/400; https://www.sandiego.gov/development-services/forms-publications/information-bulletins/114a. Checked 2026-10-22.
What this guide leaves out
- Dollar amounts for city fees. See Information Bulletin 501 and the city fee page.
- Whether a small ADU owes the city development impact fee. The bulletin lists the fee for ADUs without mentioning the exemption that state law gives ADUs of 750 sq ft or less (see the state guide), so ask Development Services how it applies to your project.
- The list of currently preapproved plans and typical plan check time.
- Rules inside the Coastal Overlay Zone. The bulletin says several recent amendments take effect there only after the Coastal Commission certifies them.
Anything you plan around should be confirmed with City of San Diego Development Services.
Thinking about an ADU as a rental? Run the rental cash flow calculator with your own rent and costs, or try the house hack calculator if you will live in the main house. Outside city limits, read the county ADU guide. For the state baseline, see California ADU rules.
FAQ
Does the City of San Diego require parking for an ADU?
Not outside the Coastal Overlay Zone. Inside it, one space is required only in the Beach Impact Area and outside a transit priority area, with several exceptions.
Can I live off site and rent out a San Diego ADU?
Yes. The city does not require the owner to live on site for an ADU. A JADU is different and generally needs the owner on site. Rentals must be at least 31 consecutive days.
How big can an ADU be in San Diego?
The maximum is 1,200 square feet, and converting existing space is not held to that cap. The minimum is 150 square feet.
How long does a San Diego ADU permit take?
The city states one timeline: 30 days for applications using preapproved plans. It gives no standard time for custom plans, so ask Development Services.