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What you can build

San Diego ADU Regulations & Zoning

KEY RULES AT GLANCE
Size and Separation

Maximum size: 1,200 square feet

Side/rear setbacks: 0 feet (4 feet preferred and for two-story)

Two story:  Yes

Building separation: 6 feet

Additional Requirements

Soils Report: No

Building Verification Survey: No

Coastal permit (in some areas): Yes

Stormwater Mitigation: No

Number of ADUs Allowed

  •  On single-family residential lots in San Diego, you are allowed to build one ADU (either attached or detached) and one Junior ADU (created from existing space in the primary residence, with an owner occupancy requirement).

    In the City of San Diego, you may also build one income-restricted affordable ADU and one additional bonus ADU (at market rates), provided that the development adheres to the zoning regulations for lot coverage.

    This means you could potentially have up to four ADUs (one ADU, one JADU, one affordable ADU, and one bonus market-rate ADU). In transit priority areas, there may be opportunities to build even more. Learn more about the City of San Diego’s affordable ADU bonus program.

  • In the City of San Diego, if your property is in a multifamily zone, you can build up to two detached ADUs, even if there’s only one house on the lot. If there are multiple existing units, you can build as many ADUs as the number of units, with a maximum of eight detached ADUs. The limit of eight will be effective starting January 2025, as per SB1211, signed by the governor in September 2024.

    For properties in a Single Dwelling Unit Zone with an existing multifamily dwelling or those located in a Multiple Dwelling Unit Zone with an existing or proposed dwelling, two ADUs (attached or detached) are permitted. This means you can build two ADUs in a multifamily zone (even if there is just one single-family residence) or in a single-family zone with an existing multifamily structure (like a duplex).

    Additionally, existing non-livable spaces such as storage areas or garages can be converted into ADUs. There is no limit on the number of ADUs that can be created through these conversions, and they are in addition to the new ADUs allowed above.

    Moreover, the City of San Diego’s ADU Bonus Program may allow for the construction of even more units.

ADU Size & Building Constraints

  • San Diego permits detached ADUs up to 1,200 square feet. Additionally, ADUs up to 800 square feet are exempt from lot coverage requirements, meaning you can build an ADU of this size even if you’ve already reached the maximum allowable lot coverage on your property.

  • In the City of San Diego, attached ADUs can be up to 1,200 square feet in size. Unlike many other local jurisdictions, the City of San Diego does not impose a size limit based on the size of the primary home.

  • In San Diego, the height of a detached ADU can be at least 16 feet, with reduced setbacks of zero feet on the side and rear yards. You can build higher than 16 feet, but it must comply with the maximum height limits for the underlying zoning and maintain 4-foot setbacks if the side or rear property line borders residentially zoned or developed properties.

    For most residential properties in San Diego, the maximum building height ranges from 24 feet to 30 feet, with some areas allowing up to 35 feet, as per Section 131.0444 of the Zoning Code.

  • Two-story ADUs are allowed in San Diego, as long as they adhere to the height requirements outlined earlier. If the ADU is located above a garage or another accessory building, the maximum height for flat-roofed structures is 21 feet, while sloped-roof structures can go up to 30 feet, as stated in Section 141.0307 (f) of the Zoning Code.

    Additionally, stairs must be at least 5 feet from the property line (or follow the underlying setbacks). For two-story units located on properties adjacent to other residential properties, a 4-foot setback is required.

  • Yes, you can stack detached ADUs on top of each other in San Diego, according to the City of San Diego Planning Department consultation from October 2021.

  • Yes, you can attach two ADUs to each other in San Diego.

  • No, a Junior Accessory Dwelling Unit (JADU) must be created from existing space within the primary residence. As of December 2023, with the Housing Action Package 2.0, the City of San Diego has closed the option to create a new JADU attached to the ADU.

  • Yes, San Diego generally allows roof decks on ADUs, but they must comply with the height restrictions for the specific zoning area. Additionally, roof decks cannot encroach into the required setbacks. Keep in mind that railings and access staircases above 42" are typically included in height calculations.

  • San Diego does not specify detailed requirements for the exterior of the ADU. However, general guidelines suggest that the exterior features, including roofing, trim, walls, windows, and color palette, should match the primary dwelling unit for aesthetic consistency.

ADU Setbacks

  • ADUs must follow front yard setback requirements, with 0′ side and rear setbacks allowed for ADUs up to 16′ in height. This means you can build up to the property line. However, if the ADU exceeds 16′ or is two stories tall, and the property line is adjacent to another residentially zoned property, 4′ side and rear setbacks are required.

    Additionally, street side setbacks must adhere to the underlying zoning regulations, not just the 4′ requirement, as confirmed by a planner in September 2023. Any open staircases must comply with the setbacks of the property, meaning they must typically be at least five feet from the property line.

    If you’re building closer than 5′ to the property line, the structure will need to be fire-rated, which increases costs. For construction, a clearance of at least 4′ from existing structures is recommended to facilitate work, although it is possible to build closer with higher costs. We recommend a setback of more than 5′ to avoid the need for a survey and reduce construction costs.

  • According to San Diego Municipal Code 131.0450, detached ADUs must maintain a minimum distance of 6 feet between the ADU and other dwellings on the same property.

    Additionally, fire codes may require special materials and possibly fire ratings for the existing primary dwelling if the distance between structures is less than 10 feet, eave to eave.

  • Yes, building an ADU in the front yard is allowed in San Diego, as long as it meets the setback requirements for the zoning of the property. Moreover, California state law allows the construction of an ADU of at least 800 square feet, even if it extends into the front setback, as long as it cannot be placed in another location on the property.

Additional Requirements

  • San Diego permits digital submission for ADU applications

  • No, San Diego does not mandate soils reports for ADUs.

  • If an ADU or JADU is constructed and the total number of ADUs or JADUs on the property reaches two or more, at least two trees must be planted for every 5,000 square feet of lot area, with a minimum of one tree per property. Any new tree required for this purpose must be selected according to the Landscape Standards in the Land Development Manual and the City’s Street Tree Selection Guide.

  • After submitting plans for pre-plan check review, the City of San Diego will typically issue an invoice for the "Plan Check Fee" within 3-5 days. This fee, which ranges from $1,500 to $2,500, must be paid before the city formally begins reviewing the plans.

    The city has up to 60 days for their first review. During this phase, they will provide corrections, which the designer must address and resubmit. Subsequent reviews typically take about 30 days. Overall, the plan review process can take approximately 90-100 days.

    Once the plans are approved, the project enters an "issuance" queue, which takes an additional 15-20 days for processing. During this period, you will also incur additional fees, including the Building Permit Fee (similar in cost to plan check fees), school impact fees (which vary by district), and minor sewer/water meter review fees.

Parking

  • The City of San Diego has largely eliminated parking requirements for ADUs. Here’s a breakdown:

    • ADUs located outside the Coastal Overlay Zone do not require parking.

    • Within the Coastal Overlay Zone, parking is only required if the property is in the Beach Impact Area (Parking Impact Overlay Zone) and not within a sustainable development area. In that case, one off-street parking space is necessary, unless any of the following apply:

      • The ADU is 500 sq ft or smaller.

      • The property is in a historic district.

      • The ADU is attached to the main residence or another accessory structure.

      • The property is within a residential permit parking district.

      • A car-share vehicle is available within one block.

    Additionally, if a garage, carport, or covered parking structure is converted or removed, replacement parking is not required—except in the Beach Impact Area of the Parking Impact Overlay Zone and outside a sustainable development area.

    Starting January 2025 (SB1211), no replacement parking will be needed when uncovered parking is removed or repurposed for an ADU.

  • If a parking space is necessary, it can be placed within the setbacks or in an existing driveway as tandem parking. Additionally, when a garage, carport, or covered parking structure is removed or converted into an ADU, the parking space does not need to be replaced.

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