ADU Permit in San Diego, CA
Permit Summary
ADU Types & Property Eligibility
ADU Type Rules
On premises with an existing or proposed single dwelling unit, the code permits one ADU within the existing or proposed dwelling or an existing accessory structure, plus one attached or detached ADU; one JADU may also be allowed under separate JADU rules. On premises with a proposed multiple-dwelling-unit structure, up to two detached ADUs are allowed. With an existing multiple-dwelling-unit structure, ADUs may be created in qualifying existing non-livable space and detached ADUs may also be added. Additional affordable and bonus ADUs may be allowed through the ADU Home Density Bonus Program subject to location, lot, fire, parking, affordability, and other program requirements.
Lot / Zoning Eligibility Rules
ADUs are a Process One limited use where the applicable use-regulation table allows them and are generally permitted in zones that allow residential uses, on a lot with an existing or proposed single dwelling unit or multiple dwelling units. An ADU or JADU generally may not be constructed on premises that used the City's Multi-Dwelling Unit and Urban Lot Split regulations for single-family zones, except where the code expressly provides otherwise. Base-zone, planned-district, overlay, environmental, and Coastal rules remain applicable.
Size, Height & Placement
Setback Rules
Conversions of existing dwelling units or accessory structures, and ADUs rebuilt in the same location and building envelope, may retain the existing setbacks. For other ADUs, the front setback follows the base zone and the street-side setback is 4 feet or the base-zone minimum, whichever is less. For ADUs 16 feet or less outside a High or Very High Fire Hazard Severity Zone, no minimum interior-side or rear setback applies, subject to any greater setback required by the Fire Code Official. In High or Very High Fire Hazard Severity Zones, a minimum 4-foot interior-side and rear setback applies. For ADUs over 16 feet outside those fire zones, no minimum side/rear setback generally applies, but where the side or rear line abuts residentially zoned or exclusively residential premises, the minimum is 4 feet or the base-zone minimum, whichever is less. Exterior stairs, balconies, decks and similar projections remain subject to applicable setback rules.
Lot Coverage / FAR Rules
ADUs are exempt from base-zone density limits, but ADU gross floor area generally counts toward floor area ratio. One attached or detached ADU of 800 square feet or less may be allowed without being subject to the underlying maximum lot coverage, maximum FAR, front-yard setback, or minimum-open-space requirements when the conditions in SDMC §141.0302(b)(4) are met. Development of multiple ADUs, including Home Density Bonus ADUs, remains subject to applicable structure-height, lot-coverage and FAR rules, with special FAR calculations for the bonus program and environmentally sensitive lands.
Attached ADU Rules
On a premises with an existing or proposed single dwelling unit, one attached ADU may be used as the additional attached-or-detached ADU allowed by §141.0302(b)(1)(B); an ADU may also be located within the existing or proposed single dwelling unit under §141.0302(b)(1)(A) and must have a separate exterior entry from the single dwelling unit. New attached ADUs must comply with applicable size, height, setbacks, building, energy and life-safety requirements. The ordinary multiple-dwelling-unit provisions authorize conversions of existing non-livable space and detached ADUs rather than new attached ADU additions.
Detached ADU Rules
Detached ADUs are allowed subject to the applicable size, height, setback, fire, parking and building-code rules. On a standard single-dwelling-unit premises, one detached ADU may be used as the attached-or-detached ADU allowed in addition to a qualifying conversion/internal ADU. A premises with a proposed multiple-dwelling-unit structure may have up to two detached ADUs. A premises with an existing multiple-dwelling-unit structure may have up to eight detached ADUs, but not more detached ADUs than existing dwelling units. In single-dwelling-unit zones that do not permit MDU development, detached ADU structures may not exceed two stories.
Conversion ADU Rules
Existing dwelling space, non-livable space, or an existing accessory structure may be converted to an ADU where the applicable configuration rules are met. A converted ADU, or an ADU reconstructed in the same location and within the same building envelope as an existing dwelling unit or accessory structure, may retain the existing setbacks. On a single-dwelling-unit lot, an ADU in an existing accessory structure may add up to 150 square feet solely for ingress and egress. Existing multiple-dwelling-unit structures may convert qualifying non-livable areas such as storage rooms, boiler rooms, passageways, attics, basements or garages, subject to the 25-percent unit-count rule.
Design, Occupancy & Parking
Design Standards
ADUs must satisfy the objective standards of the applicable base zone, planned district and overlay zones together with the California Building Standards Code. Multiple-ADU and Home Density Bonus projects remain subject to applicable height, lot-coverage and FAR limits; the bonus program also imposes tree/landscape standards. Exterior stairs, balconies, second-story decks and roof decks do not receive the ADU's side/rear setback encroachment treatment and must comply with the applicable zone setbacks.
Owner Occupancy Rules
The record owner is not required to live on the same premises as an ADU under SDMC §141.0302(b)(11). This differs from the separate rules that can apply to JADUs and from voluntary owner-occupancy commitments used to qualify for certain Development Impact Fee exemptions.
Parking Rules
No on-street or off-street parking is generally required for an ADU. One off-street space per ADU is required when the premises is in the Beach Impact Area of the Parking Impact Overlay Zone and outside a transit priority area, unless the ADU is 500 square feet or less, the premises is in a designated historic district, the ADU is attached to the primary dwelling or accessory structure, the premises is in a residential permit-parking district, or a car-share vehicle is within one block. Required or voluntary ADU parking may be in setbacks and may use tandem spaces or mechanical lifts if access standards are met. Affordable and bonus ADUs under the Home Density Bonus Program require one off-street space each when outside a transit priority area.
Rental / Short-Term Rental Rules
An ADU may not be rented for a term of less than 31 consecutive days under SDMC §141.0302(a)(8), so ordinary short-term vacation-rental use is not allowed for an ADU.
Separate Sale Rules
New or existing ADUs may be converted to condominiums and sold or conveyed separately from the primary residence when the requirements of SDMC §141.0302(f), the Subdivision Map Act, Davis-Stirling Act, and City subdivision rules are met. Lienholder consent is required for recordation; occupied units can trigger condominium-conversion rules; utility providers must be notified; and the ADU must receive final approval before the condominium plan is recorded. For the first 30 days of a sale listing, the ADU must be offered through at least two public real-estate websites or databases with a disclosure for buyers intending to use it as their primary residence. DSD states that ADUs developed through the ADU Home Density Bonus Program are not eligible for separate sale, and assisted or rent-restricted ADUs cannot be separately conveyed during the applicable restriction term.
Address, Utilities & Trade Permits
Address Rules
DSD assigns needed addresses during plan check when a Building Permit application has been submitted. A separate Street Address Request or Change application is for addresses not included in an existing building-permit application. The August 2026 fee schedule lists a $529.71 fee per new standard building address assigned with a building plan check.
Utility Connection Rules
ADU submittals require a Water Meter Data Card (DS-16), and DSD applies water/sewer plan-check and meter-related requirements based on the project and service configuration. Work for new or modified utilities in the public right-of-way or utility easements can require a Right-of-Way Permit. If an ADU is established as a condominium for separate conveyance, the applicant must notify water, sewer, gas and electric utility providers of the condominium creation and separate conveyance.
Trade Permit Rules
For common Group R-3 ADU projects, a Combination Building Permit integrates building, electrical, plumbing and mechanical review/inspection and full separate MEP plans are not normally submitted. Separate building and MEP permits are required for Multi-Dwelling Unit construction; electrical, mechanical and plumbing permits also apply when work is not exempt under the applicable code provisions. Fire-protection systems, utility work and right-of-way work can require additional permits when triggered by project scope.
Fire, Energy & Special Requirements
Fire / Life Safety Rules
An ADU is not required to add automatic fire sprinklers when sprinklers are not required for the primary dwelling unit. An ADU must be sprinklered when it is on premises where the primary dwelling unit is protected by an automatic sprinkler system, and constructing a detached ADU does not by itself trigger sprinklers in the existing primary dwelling or MDU unless the California Building Standards Code requires them. All affordable and bonus ADUs under the Home Density Bonus Program require automatic fire sprinklers. Plans must address applicable smoke and carbon-monoxide alarms, fire separation, exterior-wall/opening protection, egress and other California Building Standards Code requirements. High and Very High Fire Hazard Severity Zones impose additional setback and, for the bonus program, evacuation-access conditions.
Energy / Solar Rules
Title 24 energy calculations are part of the minimum ADU submittal. Newly constructed, non-manufactured detached ADUs are subject to California Energy Code photovoltaic requirements; the solar panels may be installed on the ADU or the primary dwelling. ADUs created within existing space or as additions to existing homes, including conversion of an existing detached nonresidential building to residential space, are not subject to that ADU solar-PV requirement.
Special Area / Overlay Rules
Coastal Overlay Zone projects are subject to the certified Local Coastal Program and additional coastal rules. DSD requires a Coastal Development Permit for an ADU in the Coastal Overlay Zone when the unit is not completely contained in the existing primary structure, increases habitable area, or converts non-habitable space; qualifying projects in the non-appealable area may receive the City-issued CDP through Process One when the required findings are made. As of the current City regulatory-update materials, the 2025 ADU/JADU amendments in Ordinance O-21989 are effective outside the Coastal Zone and are not yet listed as approved within the Coastal Zone. High and Very High Fire Hazard Severity Zones, environmentally sensitive lands, historical-resource review, and other overlays can impose additional siting, setback, access, landscape or review requirements.
Development / Impact Fee Rules
Under current SDMC §142.0640(b), ADUs under 750 square feet are exempt from Development Impact Fees. The first two ADUs on a premises are also exempt regardless of gross floor area, except for specified ADUs constructed under the City's Multi-Dwelling Unit Development rules; when more than two ADUs are proposed, the exemption applies to the two smallest. An additional exemption is available for ADUs when the record owner records the required affidavit committing to occupy one dwelling on the premises as a primary residence for at least three years, subject to the code's exceptions. Applicable DIFs must be paid before final inspection. More than one ADU also triggers RTCIP fees under DSD guidance, and school, inclusionary-housing, Home Density Bonus Community Enhancement, and other fees may apply depending on the project.
Preapproved Plans
Preapproved Plan Rules
San Diego accepts preapproved ADU plans from the County of San Diego, City of Chula Vista and City of Encinitas. Applications using preapproved plans are subject to a 30-day review but must still comply with San Diego development regulations and current adopted codes and standards at the time of submittal. Applicants must obtain any required license directly from the plan provider. DSD also accepts applications to establish additional preapproved plans through its master-plan process.
Permit & Review Path
Permit / Review Path
Submit through the DSD online Development Services Application Portal under Building Construction. Depending on occupancy, dwelling-unit count and structure design, DSD issues either a Combination Building Permit or a Building Permit; common detached or attached Group R-3 ADUs use a Combination Building Permit, while projects that do not qualify use a Building Permit. Accepted preapproved ADU plans receive a 30-day review. Coastal projects may require a Coastal Development Permit in addition to the building-permit review, and Home Density Bonus projects require the applicable affordability/program approvals and agreement before issuance.
Inspections
Inspection Stages
All construction must be inspected and approved before work is concealed, occupied or placed in use. Typical stages, as applicable to the ADU scope, include a pre-construction meeting when required; underground utilities; foundation; floor systems; exterior wall framing; roof framing/sheathing; all-frame-and-rough inspection covering framing and rough electrical, mechanical, plumbing, fire alarm and sprinkler work; insulation; lath or gypsum board; any required accessibility, site-development, engineering, special, structural-observation or fire-system inspections; and final inspection after dependent approvals are complete. Group R-3 Combination Building Permit projects are generally inspected by Combination Inspectors; Building Permit projects use structural, mechanical, electrical and life-safety inspectors as applicable.
What You Need Before Applying
Requirements
Obtain the applicable Combination Building Permit or Building Permit through DSD and comply with current San Diego Municipal Code zoning, California Building Standards Code, energy, storm-water, utility, and applicable overlay requirements. Confirm the lot's zoning and overlays, allowable ADU configuration and count, size, height, setbacks, parking conditions, utility needs, and any Coastal Development Permit or other site-specific approval before permit issuance.
Exemptions
There is no general Building Permit exemption for creating an ADU. DSD states that a Building Permit is required to create an ADU and that there are no exemptions. Some ADU configurations receive zoning or fee exemptions, but those do not eliminate the building-permit requirement.
Required Documents
Minimum ADU submittal materials include a site plan and vicinity map; floor and roof plans; elevations and sections as applicable; structural plans and details; structural and/or truss calculations as applicable; Title 24 energy calculations; General Application DS-3032; Water Meter Data Card DS-16; and Storm Water Applicability Checklist DS-560. Additional documents are required when the project triggers coastal, fire, grading, utility, subdivision, affordable-housing, or other specialized review.