How San Diego Handles Accessory Structures: A Practical Guide
San Diego maintains 196 local ordinances across all categories, and 6 of those deal specifically with accessory structures. Here is a breakdown of what the city actually requires, what is prohibited, and where San Diego falls on the strict-to-permissive spectrum compared to other cities.
ADU Impact Fees
San Diego waives development impact fees for the first two ADUs on a property and for any ADU under 750 square feet, removing one of the biggest cost barriers to building a backyard unit.
Key details: First 2 ADUs: Exempt from impact fees. ADUs under 750 sq ft: Automatically exempt. Owner-occupancy exemption: 3-year signed affidavit required. Fee due: Before final inspection.
Unpaid Development Impact Fees block final inspection, so the ADU cannot be legally occupied until the fee is paid or the exemption affidavit is properly recorded with the County Recorder.
ADU Rental Restrictions
San Diego bars renting an accessory dwelling unit for stays shorter than 31 consecutive days, closing off short-term vacation rental use of ADUs while leaving JADUs free of any minimum-stay limit.
Key details: Minimum ADU rental term: 31 consecutive days. JADUs: No minimum-stay limit. Rule source: Zoning code, not STRO. Applies: Citywide, all base zones.
Advertising or renting an ADU for stays under 31 days is a zoning violation Code Enforcement can cite, separate from any short-term rental permit issue.
This is not one of those rules that cities tend to ignore. San Diego actively enforces its adu rental restrictions requirements.
Garage Conversions
San Diego permits garage conversions to ADUs under state law (Government Code 65852.2) without requiring replacement parking. Conversions must meet Building Code standards for habitable space including egress, ventilation, insulation, and fire separation. Permits required through Development Services.
Key details: Replacement Parking: Not required. Ceiling Height: 7 feet minimum. Permit Required: Yes, through DSD. Impact Fees: Waived under 750 sq ft. Code: CA Gov Code 65852.2 + SDMC.
Unpermitted conversions subject to code enforcement and double permit fees. Non-compliant conversions may be ordered restored to original condition or brought into compliance.
San Diego is more permissive than most cities when it comes to garage conversions. That said, there are still limits.
Shed & Carport Rules
A detached one-story storage shed or playhouse in San Diego skips the Building Permit if its roof area is 120 square feet or less and it isn't used for a separately regulated use.
Key details: Governing section: SDMC §129.0203(a)(1). Exempt size: 120 sq ft roof area or less. Story limit: One-story, ground-supported. Over the limit: Full Building Permit required.
Building a shed over 120 square feet, or one used for a separately regulated use, without a Building Permit can trigger stop-work orders and after-the-fact permit fees from the Building Official.
The rules around shed & carport rules in San Diego lean permissive, but that does not mean anything goes.
ADU Rules
San Diego permits ADUs under SDMC Chapter 14, Article 1, Division 3, consistent with California ADU law (Government Code 65852.2). Single-family lots may have one ADU, one JADU, and one converted ADU. No owner-occupancy requirement. Permit timeline typically 3-5 months. SB 1211 (2024) allows up to 8 ADUs.
Key details: Max Detached ADU: 1,200 sq ft. JADU Size: 150-500 sq ft. Rear/Side Setback: 4 feet. Parking: Not required. SB 1211 (2025): Up to 8 ADUs.
Unpermitted ADUs subject to code enforcement. The City offers a process to legalize unpermitted ADUs under Information Bulletin 242. Fines for unpermitted construction.
Tiny Homes
Movable tiny houses are allowed citywide as an accessory structure with a Process One permit, capped at 430 square feet and limited to one per lot.
Key details: Size range: 150-430 sq ft. Max per lot: One, plus ADU/JADU. Min rental term: 30 consecutive days. Side setback: 5 ft from lot line. Permit process: Process One (limited use).
Building without the required Process One clearance, or a unit that fails to meet the size, siting, or NFPA/ANSI certification standards, is subject to standard code enforcement action and permit revocation under Chapter 12's enforcement provisions.
The Bottom Line
Compared to many U.S. cities, San Diego gives residents more room on accessory structures. 2 of the 6 rules here are rated permissive. But permissive does not mean unregulated. There are still requirements, and the city does enforce them when violations are reported.
All of the above reflects San Diego's municipal code as of our last review. If you need specifics on fines, exemptions, or filing requirements, the detailed ordinance pages linked above have the full breakdown.