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: size varies by zoning — see official source (max height: varies — see official source). Attached ADU: size varies by zoning — see official source. Junior ADU (JADU): up to 500 sq ft — must be within the existing primary dwelling or accessory structure.
| Type | Max Size | Max Height |
|---|---|---|
| Detached ADU | See official source | See official source |
| Attached ADU | See official source | See official source |
| JADU | 500 sq ft · Verified May 22, 2026 · Source | 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: Impact fees waived for ADUs under 750 sqft per Government Code §66311.5(c)(1) (formerly §66324).. School fees: School developer fees exempt for ADUs under 500 sqft per California Government Code §66311.5(c)(3) and Education Code §17620. ADUs 500+ sqft subject to school developer fees.. Total estimated permit cost: Varies.
| 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 | Impact fees waived for ADUs under 750 sqft per Government Code §66311.5(c)(1) (formerly §66324). |
| School Fees | School developer fees exempt for ADUs under 500 sqft per California Government Code §66311.5(c)(3) and Education Code §17620. ADUs 500+ sqft subject to school developer fees. |
| Total Estimate | See official source |
Permit Timeline
San Diego ADU Permit Timeline: The permitting agency shall either approve or deny the application to create or serve an accessory dwelling unit within 60 days from the date the permitting agency receives a completed application if there is an existing single-family or multifamily dwelling on the lot. Note: SD DSD ADU permit typically 3-6 weeks for plan check; standard plan program available at https://www.sandiego.gov/development-services/permits (operational, not codified). 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: follows zone standard. Side setback: no minimum. Rear setback: no minimum.
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 §66322(a)(1).
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 Urban Lot Split per Gov Code §66411.7)
- 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 §66323(a)(3). Urban Lot Split (Gov Code §66411.7) permits up to 4 units on qualifying single-family lots in urbanized areas. San Diego adopted Urban Lot Split 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 §66323(a)(3)
Statewide Preemption
ADU Preemption
California state law preempts local ADU rules — local governments cannot impose stricter standards.
View California preemption detailsState Law & Preemption
State Preemption: California Government Code Chapter 13 (§§66314–66333, effective January 1, 2025 per Stats. 2024 Ch. 7, SB 477) preempts San Diego's local ADU restrictions. San Diego must permit ADUs by-right on all 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. Owner-occupancy requirement eliminated per §66315 (AB 68, 2019; Stats. 2024 Ch. 7 §20).
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 The permitting agency shall either approve or deny the application to create or serve an accessory dwelling unit within 60 days from the date the permitting agency receives a completed application if there is an existing single-family or multifamily dwelling on the lot. Note: SD DSD ADU permit typically 3-6 weeks for plan check; standard plan program available at https://www.sandiego.gov/development-services/permits (operational, not codified).. 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?
San Diego parking rules for ADUs: 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 §66322(a)(1).
Do I have to live on-site to have an ADU in San Diego?
Owner-occupancy requirement in San Diego: No additional standards, other than those provided in Section 66314, shall be used or imposed, including an owner-occupant requirement, except that a local agency may require that the property may be used for rentals of terms 30 days or longer.
Source: San Diego Land Development Code Section 141.0302; California Government Code Chapter 13 §§66314–66333 (Stats. 2024 Ch. 7 §20). Last verified April 5, 2026. View source