San Diego ADU Rules and Permits

San Diego ADU requirements changed several times in 2025 and 2026. This guide sums up the City of San Diego's current rules from its own pages. It does not replace the City's code, and rules can change, so confirm details with the City's Development Services Department before you design or build. Fee amounts are on our ADU cost page and San Diego page.

Size and height

New attached or detached ADUs can be 150 to 1,200 square feet [1].
Converting an existing structure is not held to the 1,200 square foot limit [1].
Garage or carport space under an ADU does not count toward its square footage [2].
On lots that allow single-dwelling homes but not multiple dwellings, a detached ADU can be no more than two stories. It must also meet the zone's height limit [1].

Setbacks

A detached ADU must meet the zone's front setback, but one ADU of 800 square feet or less may extend into it [1].
An ADU taller than 16 feet next to a residential property needs at least a 4 foot interior side setback [1].
In a Very High Fire Hazard Severity Zone, an ADU needs at least 4 feet on the interior side and rear, no matter its height [1].
Exterior stairs, balconies, second-story decks, and roof decks may not extend into setbacks [2].

Parking

No parking spaces are required for ADUs outside the Coastal Overlay Zone, and none are required for JADUs [1]. There are exceptions. A garage conversion in the Beach Impact area outside a Transit Priority Area needs one replacement space, and each Affordable or Bonus ADU outside a Transit Priority Area needs one off-street space [2].

ADU vs JADU

Cutaway illustration of a house with a junior ADU room inside it — A JADU sits inside the main home and can have its own entrance.

A JADU is 150 to 500 square feet and sits entirely inside a single-family home [2]. JADUs may not be built inside detached garages or other ADUs [3]. Since January 1, 2026, state law requires the owner to live on site with a JADU only if it shares a bathroom or sanitation with the main home, and JADU rentals must be longer than 30 days [3].

How many units you can add

On a single-dwelling lot, the City allows one main home, one attached or detached ADU, one converted ADU, and one JADU [1]. On lots with an existing multifamily building, state law allows up to eight detached ADUs, capped at the number of existing units [3].

The ADU bonus program

The City cut back its ADU Home Density Bonus Program in 2025. Starting August 22, 2025, outside the Coastal Zone, bonus ADUs are no longer allowed in several low-density RS-1 zones, with exceptions in some high-opportunity areas [3]. Where it still applies, bonus ADUs are capped at 4 on lots of 8,000 square feet or less, 5 on lots of 8,001 to 10,000, and 6 on larger lots [1].

Renting and selling

The owner does not have to live on site for an ADU [1].
An ADU may not be rented for less than 31 days in a row [1].
Most new or existing ADUs can now be sold separately as condominiums [4]. The ADU must pass final inspection before the condo plan is recorded [2].

Permit steps

Confirm your property is in the City of San Diego and check its zone, including coastal and fire overlays.
Choose a design. Preapproved plans from the County of San Diego, Chula Vista, and Encinitas are accepted [2].
Apply for a building permit online. A building permit is required for every ADU or JADU, with no exemptions [1].
Respond to plan review comments. Preapproved plans get a 30-day review [1]. Since January 1, 2026, the City must finish a completeness check on ADU applications within 15 business days [3].
Pay fees, get the permit, build, and pass final inspection.

Coastal and fire zones

Inside the Coastal Overlay Zone, a Coastal Development Permit is generally required, with some exceptions [1]. Some recent rule changes took effect in the Coastal Zone later than elsewhere. For example, Housing Action Package 2.0 took effect there on March 11, 2026 [3]. In fire hazard zones, plan for the 4 foot setbacks above.

Recent changes at a glance

Date	Change
Aug. 22, 2025	Bonus program limits take effect outside the Coastal Zone [3]
Aug. 27, 2025	City confirms most ADUs can be sold as condos [4]
Jan. 1, 2026	JADU fee and owner rules; 15 business day completeness check [3]
March 11, 2026	Housing Action Package 2.0 takes effect in the Coastal Zone [3]
July 2026	2026 Land Development Code update takes effect outside the Coastal Zone [3]

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Sources

City of San Diego Development Services, "Information Bulletin 400: Accessory Dwelling Unit/Junior Accessory Dwelling Unit," January 2026. Fetched 2026-11-11. https://www.sandiego.gov/development-services/forms-publications/information-bulletins/400
City of San Diego Development Services, "Accessory Dwelling Unit/Junior Accessory Dwelling Unit," no date shown. Fetched 2026-11-11. https://www.sandiego.gov/development-services/news-programs/programs/companion-junior-units
City of San Diego Development Services, "Regulatory Updates," no date shown. Fetched 2026-11-11. https://www.sandiego.gov/development-services/regulatory-updates
City of San Diego Development Services, "Public Notice: Information Bulletin 400 Updates," August 27, 2025. Fetched 2026-11-11. https://www.sandiego.gov/sites/default/files/2025-08/dsd_ib400_adu.pdf