ADU Rules in San Diego, CA (2026)
ADU rules, permit requirements, size limits, and fees for San Diego, CA. Source-cited from official municipal code.
Yes, ADUs are allowed in San Diego, CA.
San Diego, CA permits accessory dwelling units (ADUs) on residential properties. ADUs — also called granny flats, in-law units, backyard cottages, or secondary suites — are secondary housing units on a single-family or multifamily lot. California state law actively preempts local restrictions, making ADU approval a streamlined ministerial process. In San Diego, the San Diego Development Services Department (DSD) handles ADU permit applications. Below you will find the current size limits, setbacks, fees, and timeline for building an ADU in San Diego.
ADU Size Limits
ADU Size Limits in San Diego: Detached ADU: up to 1200 sq ft (max height: 16 feet). Attached ADU: 50% of primary dwelling up to 1200 sqft. Junior ADU (JADU): up to 500 sq ft — must be within the existing primary dwelling or accessory structure. Detached ADU maximum 1,200 sqft per California Gov Code 65852.2(c)(2)(B). JADU up to 500 sqft within existing residential structure. San Diego LDC Section 141.0302 provides local ADU standards consistent with state law.
| Type | Max Size | Max Height |
|---|---|---|
| Detached ADU | 1200 sq ft | 16 feet |
| Attached ADU | 50% of primary dwelling up to 1200 sqft | Same as primary dwelling height limit per zone |
| JADU | 500 sq ft | Within existing structure |
Permit Fees
ADU Permit Fees in San Diego: Plan check fee: Varies — typically $600–$2,500 for standard ADU based on project valuation. Building permit fee: Varies by valuation — typically $1,500–$5,500. Impact fees: None. School fees: Exempt for ADUs under 750 sqft per Gov Code 65852.2(f)(3). ADUs 750+ sqft subject to school developer fees.. Total estimated permit cost: $2,500–$9,000 total permit fees depending on size and scope. Impact fees waived for ADUs under 750 sqft. DSD fee schedule: https://www.sandiego.gov/development-services/news-programs-and-resources/fee-schedule. San Diego also offers Standard ADU Plan Program for reduced plan check time.
| Fee Type | Amount |
|---|---|
| Plan Check | Varies — typically $600–$2,500 for standard ADU based on project valuation |
| Building Permit | Varies by valuation — typically $1,500–$5,500 |
| Impact Fees | None |
| School Fees | Exempt for ADUs under 750 sqft per Gov Code 65852.2(f)(3). ADUs 750+ sqft subject to school developer fees. |
| Total Estimate | $2,500–$9,000 total permit fees depending on size and scope |
Permit Timeline
San Diego ADU Permit Timeline: Ministerial approval within 60 days per Gov Code 65852.2(a)(3). San Diego Development Services Department (DSD) ADU permit typically 3-6 weeks for plan check. Standard plan program available at: https://www.sandiego.gov/development-services/news-programs-and-resources/programs/adu Apply through the San Diego Development Services Department (DSD) online permit portal. Phone: (619) 446-5000.
Setback Requirements
ADU Setback Requirements in San Diego: Front setback: Same as zone standard. Side setback: 4 feet. Rear setback: 4 feet. 4-foot side and rear setbacks required for new detached ADUs per Gov Code 65852.2(c)(2)(E). No setback required for ADU replacing structure in same footprint. Front setback follows applicable LDC zone standards. Canyon and coastal overlay zones may have additional setback requirements.
Parking Requirements
Parking Requirements: No additional parking required for ADUs within one-half mile of transit or when garage/carport is converted to ADU. San Diego MTS and NCTD transit networks cover much of the city. Per California Gov Code 65852.2(d)(1)(A).
Restrictions & Requirements
- ADU must comply with objective LDC standards
- Canyon-edge development restrictions may apply in hillside areas
- Coastal Zone ADUs subject to California Coastal Commission requirements
- ADU cannot be sold separately from primary dwelling (except under SB 9)
- ADU must have permanent foundation
- Fire sprinkler requirements vary by project scope
How Many ADUs Are Allowed?
Number of ADUs Allowed in San Diego: Single-family lots: 1 ADU + 1 JADU per single-family lot. Multifamily properties: Up to 25% of existing units (minimum 2) as detached ADUs; 1 ADU per existing unit for internal conversions per Gov Code 65852.2(e). SB 9 Urban Lot Split permits up to 4 units on qualifying single-family lots in urbanized areas. San Diego adopted SB 9 ministerial approval per state mandate.
Single-Family Lots
1 ADU + 1 JADU per single-family lot
Multifamily Properties
Up to 25% of existing units (minimum 2) as detached ADUs; 1 ADU per existing unit for internal conversions per Gov Code 65852.2(e)
State Law & Preemption
State Preemption: California Government Code Section 65852.2 preempts local ADU restrictions. San Diego must permit ADUs by-right on all single-family and multifamily residential lots. San Diego also adopted its own ADU ordinance (LDC Article 1, Division 1) that layers additional local facilitation on top of state requirements.
Historic District Considerations
Historic District Requirements: San Diego has 8 historic districts where additional design review may be required for ADU construction. Design review approval is required before obtaining a building permit for properties in historic overlay zones. San Diego has 8 designated historic districts including: Barrio Logan, Heritage Park Victorian Village, Mission Hills, Normal Heights/Kensington Craftsman, North Park, Old Town San Diego, Spruce Street Suspension Bridge area, and University Heights. Individually designated Historic Resources also exist. Design review required for exterior alterations visible from public right-of-way. SD Historical Resources Board oversees review. Look up historic district boundaries at: https://www.sandiego.gov/planning/programs/historical
Frequently Asked Questions
Can I build an ADU in San Diego?
Yes. San Diego, CA allows accessory dwelling units. On a single-family lot you can build 1 ADU + 1 JADU per single-family lot.
How big can an ADU be in San Diego?
The maximum size for a detached ADU in San Diego is 1,200 square feet. A Junior ADU (JADU) can be up to 500 square feet.
How long does it take to get an ADU permit in San Diego?
The typical ADU permit timeline in San Diego is Ministerial approval within 60 days per Gov Code 65852.2(a)(3). San Diego Development Services Department (DSD) ADU permit typically 3-6 weeks for plan check. Standard plan program available at: https://www.sandiego.gov/development-services/news-programs-and-resources/programs/adu. Total estimated permit fees are $2,500–$9,000 total permit fees depending on size and scope.
Do I need extra parking for an ADU in San Diego?
No, San Diego does not require additional parking for ADUs.
Do I have to live on-site to have an ADU in San Diego?
No, owner-occupancy is not required for ADUs in San Diego.
Source: San Diego Land Development Code Section 141.0302; California Government Code Section 65852.2. Last verified April 5, 2026. View source