San Diego ADU Regulations: What You Need to Know
Navigate San Diego's ADU rules with confidence. From setbacks to permits, understand what's required before you build.
California Has Made ADUs Easier Than Ever to Build
California has passed landmark legislation to streamline ADU construction statewide. Key laws including SB 9, AB 68, AB 881, and AB 1033 have eliminated many barriers that previously made ADUs difficult or impossible to permit.
These laws prevent cities from imposing minimum lot sizes, limit setback requirements, cap parking mandates, and require permit approval within 60 days. San Diego has updated its municipal code to comply, making the city one of the most ADU-friendly in the state.
The result: if you own residential property in San Diego, you almost certainly have the right to build at least one ADU. BNC Builders navigates these regulations daily and handles every aspect of compliance for our clients.
Key State Laws You Should Know
SB 9 (2021)
Allows lot splits and duplexes on single-family lots, creating new ADU opportunities on subdivided parcels.
AB 68 & AB 881 (2020)
Eliminated minimum lot sizes, reduced setbacks to 4 feet, capped parking requirements, and set 60-day approval deadlines.
AB 1033 (2024)
Allows ADUs to be sold as condominiums separately from the primary dwelling, creating new ownership possibilities.
SB 897 (2023)
Increased maximum height for detached ADUs to 18 feet near transit and allows two-story ADUs in more situations.
San Diego ADU Requirements in 2026
These are the primary dimensional and zoning requirements for building an ADU in San Diego. BNC Builders evaluates your specific property against all requirements during our free feasibility assessment.
Rear & Side Setbacks
4 feet
Detached ADUs must be set back at least 4 feet from rear and side property lines. This is a statewide standard under California ADU law, overriding local setback requirements that may have been larger.
Maximum Height
16 feet (detached)
Detached ADUs can be up to 16 feet tall, or 18 feet in some cases near transit. Attached ADUs must conform to the height of the primary dwelling. Two-story detached ADUs may be permitted up to 18 feet.
Maximum Size
1,200 sq ft
Detached ADUs can be up to 1,200 square feet. Attached ADUs can be up to 50% of the primary dwelling floor area. JADUs are limited to 500 square feet and must be within the existing home footprint.
Lot Coverage
No minimum lot size
California law prohibits cities from imposing minimum lot size requirements for ADUs. San Diego cannot deny an ADU based on lot size, floor area ratio, or lot coverage if the unit meets setback requirements.
ADU Parking Rules in San Diego
One of the biggest changes in California ADU law is the relaxation of parking requirements. Most San Diego ADU projects qualify for a complete parking exemption, removing what was historically one of the largest obstacles to ADU construction.
Parking Exemption Check
Your ADU likely qualifies for a parking exemption if any of these apply:
Not sure if you qualify? Ask BNC Builders during your free consultation.
ADU Permit Timeline in San Diego
The complete ADU permit and construction process typically takes 8 to 14 months from start to finish. Here is what each phase looks like.
Feasibility Assessment
1 - 2 weeksEvaluate your property for ADU potential, including zoning verification, utility access, and site constraints. BNC Builders performs this assessment during your free consultation.
Design & Engineering
4 - 8 weeksCreate architectural plans, structural engineering, Title 24 energy calculations, and any required reports (soil, survey). Plans must comply with California Building Code and local amendments.
Plan Submittal
1 - 2 weeksSubmit complete plan sets to the City of San Diego Development Services Department. Include all required forms, fees, and supporting documents. BNC Builders handles the entire submittal process.
Plan Review
4 - 8 weeksThe city reviews plans for code compliance. San Diego is required to process ADU permits within 60 days of a complete application under state law. Corrections may extend the timeline.
Permit Issuance
1 - 2 weeksOnce plans are approved, pay remaining permit fees and receive your building permit. Construction can begin immediately after permit issuance.
Construction & Inspections
4 - 8 monthsBuild the ADU with required inspections at each phase: foundation, framing, rough electrical/plumbing, insulation, and final. Each inspection must pass before the next phase begins.
BNC Builders Handles All Permits
You should not have to navigate San Diego's permitting process alone. Our team prepares all documentation, submits plans, responds to corrections, and coordinates inspections. We have established relationships with the Development Services Department and know how to keep your project moving.
ADU Regulations in Escondido
As a BNC Builders home base, we have deep expertise in Escondido's specific ADU ordinances. While Escondido must comply with state ADU law, the city has its own submission requirements and review process that differ from the City of San Diego.
Escondido processes ADU permits through its Building Division and typically completes plan review within the state-mandated 60-day window. The city has been increasingly supportive of ADU construction as part of its housing element compliance.
Common ADU Permit Documents
These are the typical documents required for an ADU permit application in San Diego County:
- Architectural plans (site plan, floor plan, elevations)
- Structural engineering calculations
- Title 24 energy compliance report
- Soil/geotechnical report (if required)
- Plot plan showing setbacks and easements
- Utility connection plan (water, sewer, electrical)
- Completed permit application forms
- Owner authorization and property deed
ADU Regulation Questions Answered
Do I need a permit to build an ADU in San Diego?
Yes, all ADUs in San Diego require a building permit from the City of San Diego Development Services Department. This includes detached ADUs, attached ADUs, garage conversions, and JADUs. California law requires cities to approve ADU permits within 60 days of receiving a complete application. BNC Builders manages the entire permitting process for you.
Can I build an ADU on any residential property in San Diego?
Under California ADU law (effective January 2020 and updated through 2024), at least one ADU is allowed on any residential lot, including single-family and multi-family properties. There is no minimum lot size requirement. The city cannot deny an ADU based on lot coverage or floor area ratio if the unit is no larger than 800 square feet.
What are the setback requirements for ADUs in San Diego?
Detached ADUs require a minimum 4-foot setback from rear and side property lines. No front setback is required beyond what exists for the primary dwelling. For ADUs no larger than 800 square feet, the city cannot impose setbacks greater than 4 feet. Attached ADUs follow the same setback rules as the primary structure.
How long does it take to get an ADU permit in San Diego?
The full permitting process typically takes 3 to 6 months from initial design to permit issuance. Plan review by the City of San Diego must be completed within 60 days of a complete application per state law. Design and engineering take an additional 4 to 8 weeks beforehand. BNC Builders expedites this by submitting complete, code-compliant plans that minimize correction cycles.
Can I rent out my ADU in San Diego?
Yes, you can rent out your ADU as a long-term rental. However, California law (AB 1033, effective 2024) also allows ADUs to be sold separately from the primary dwelling in some cases. Short-term rentals (under 30 days) of ADUs are generally restricted in San Diego unless the property is owner-occupied. Always check current local regulations.
Do I need to add parking for my ADU?
In most cases, no additional parking is required. Parking exemptions apply if your ADU is within half a mile of public transit, is a conversion of existing space, or is in a historic district. When parking is required, only one space per ADU is the maximum. This space can be tandem or located in setback areas including the front yard.
What is the difference between an ADU and a JADU in San Diego?
A Junior ADU (JADU) is created within the existing footprint of the primary residence and must be 500 square feet or less. It requires an interior connection to the main home (which can be a door that locks from both sides) and may share a bathroom with the primary dwelling. JADUs have a simplified permit process and lower costs. A standard ADU is a fully independent dwelling with its own kitchen, bathroom, and entrance.
BNC Builders Handles All ADU Permits for You
Skip the stress of navigating San Diego ADU regulations. Our team manages every permit, document, and inspection from start to finish.