ADU Rules in San Jose, CA (2026)
ADU rules, permit requirements, size limits, and fees for San Jose, CA. Source-cited from official municipal code.
Yes, ADUs are allowed in San Jose, CA.
San Jose, 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 Jose, the San Jose Department of Planning, Building and Code Enforcement (PBCE) — Building Division handles ADU permit applications. Below you will find the current size limits, setbacks, fees, and timeline for building an ADU in San Jose.
ADU Size Limits
ADU Size Limits in San Jose: 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 §66314(d)(5). JADU up to 500 sqft within existing residential structure or garage. Garage conversion ADUs limited to existing footprint plus 150 sqft for ingress/egress. San Jose Municipal Code Title 20 governs locally.
| Type | Max Size | Max Height |
|---|---|---|
| Detached ADU | 1200 sq ft · Verified May 25, 2026 · 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 Jose: Plan check fee: Varies — typically $700–$2,800 for standard ADU based on valuation. Building permit fee: Varies by valuation — typically $1,800–$5,500. Impact fees: None. School fees: Exempt for ADUs under 750 sqft per California ADU fee exemption framework (§§66314–66333; school fee exemption codified in Health and Safety Code). ADUs 750+ sqft subject to school developer fees at applicable school district rates.. Total estimated permit cost: $2,500–$8,500 total permit fees depending on size and scope. Impact fees waived for ADUs under 750 sqft per California ADU framework (§§66314–66333; school/impact fee exemptions in H&S Code). San Jose PBCE fee schedule: https://www.sanjoseca.gov/your-government/departments-offices/planning-building-code-enforcement/building/fee-schedule
| Fee Type | Amount |
|---|---|
| Plan Check | Varies — typically $700–$2,800 for standard ADU based on valuation |
| Building Permit | Varies by valuation — typically $1,800–$5,500 |
| Impact Fees | None |
| School Fees | Exempt for ADUs under 750 sqft per California ADU fee exemption framework (§§66314–66333; school fee exemption codified in Health and Safety Code). ADUs 750+ sqft subject to school developer fees at applicable school district rates. |
| Total Estimate | See official source |
Permit Timeline
San Jose 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: SJ PBCE ADU permits typically 3-6 weeks plan check; portal: https://www.sanjoseca.gov/your-government/departments-offices/planning-building-code-enforcement/building (operational, not codified). Apply through the San Jose Department of Planning, Building and Code Enforcement (PBCE) — Building Division online permit portal. Phone: (408) 535-3555.
Setback Requirements
ADU Setback Requirements in San Jose: 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 §66314(d)(7). No setback for ADU replacing existing structure in same footprint. Front setback follows applicable zone standards. San Jose Municipal Code Title 20.
Parking Requirements
Parking Requirements: No additional parking required for ADUs within one-half mile of VTA or BART transit stations. Garage/carport conversion ADUs require no replacement parking. Per California Gov Code §66322(a)(1).
Restrictions & Requirements
- ADU must comply with objective Municipal Code zoning standards
- ADU cannot be sold separately from primary dwelling (except under Urban Lot Split per Gov Code §66411.7)
- ADU must have permanent foundation
- Hillside and Alquist-Priolo Fault Zone areas have additional structural requirements
- Fire sprinkler requirements apply for new ADU construction above certain thresholds
How Many ADUs Are Allowed?
Number of ADUs Allowed in San Jose: 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 Jose adopted Urban Lot Split ministerial approval per state mandate.
Single-Family Lots
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)
State Law & Preemption
State Preemption: California Government Code Chapter 13 (§§66314–66333, effective January 1, 2025 per Stats. 2024 Ch. 7, SB 477) preempts San Jose's local ADU restrictions. San Jose must permit ADUs by-right on all residential lots. Owner-occupancy requirement eliminated per §66315 (AB 68, 2019; Stats. 2024 Ch. 7 §20). San Jose adopted local ADU ordinance consistent with state law requirements. State preemption is now codified in Chapter 13 (Stats. 2024 Ch. 7 §20).
Historic District Considerations
Historic District Requirements: San Jose has 5 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 Jose has several historic districts including: Naglee Park, Willow Glen, Rose Garden, Vendome, and St. Leo's/Sacred Heart. Individually designated Historic Landmarks also exist (San Jose City Hall, Egyptian Theatre, Dr. Martin Luther King Jr. Library, etc.). Design review required for exterior modifications to designated structures or properties in historic districts. San Jose Historic Landmarks Commission oversees review. Look up historic district boundaries at: https://www.sanjoseca.gov/your-government/departments/planning-building-code-enforcement/planning/historic-preservation
Frequently Asked Questions
Can I build an ADU in San Jose?
Yes. San Jose, 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 Jose?
The maximum size for a detached ADU in San Jose 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 Jose?
The typical ADU permit timeline in San Jose 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: SJ PBCE ADU permits typically 3-6 weeks plan check; portal: https://www.sanjoseca.gov/your-government/departments-offices/planning-building-code-enforcement/building (operational, not codified).. Total estimated permit fees are $2,500–$8,500 total permit fees depending on size and scope.
Do I need extra parking for an ADU in San Jose?
San Jose parking rules for ADUs: No additional parking required for ADUs within one-half mile of VTA or BART transit stations. Garage/carport conversion ADUs require no replacement parking. Per California Gov Code §66322(a)(1).
Do I have to live on-site to have an ADU in San Jose?
Owner-occupancy requirement in San Jose: 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 Jose Municipal Code Title 20; California Government Code Chapter 13 §§66314–66333 (Stats. 2024 Ch. 7 §20). Last verified April 5, 2026. View source