How to Get a ADU Permit in San Jose, CA (2026 Guide)
Everything you need to know about adu permits in San Jose, CA, local requirements, fees, timelines, and how to apply.
By Joey, Founder · Last updated May 15, 2026 · How we research →
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Free Permit Lookup →Do You Need a ADU Permit in San Jose?
Based on San Jose's local building codes, you'll need a permit when:
Detached ADUs (new separate structures) require full building permits including electrical, plumbing, and mechanical. California has state-level ADU preemption laws that may streamline the process.
Converting an existing space (garage, basement, or other area) to an ADU requires building, electrical, and plumbing permits. The conversion must meet all residential building code requirements for habitable space including egress, insulation, ceiling height, and ventilation.
Attached ADUs (additions to the existing house) require full building permits including all trades. This is treated as a room addition with the additional requirement of meeting ADU-specific zoning rules for independent living space.
Permit Fees in San Jose
Based on local San Jose permit data, fees for adu projects typically range:
Here's how fees break down by project scope nationally:
| Project Scope | Typical Permit Fee |
|---|---|
| Garage or basement conversion ADU | $500 – $3,000 |
| Attached ADU (addition) | $800 – $5,000 |
| Detached ADU (new construction) | $1,000 – $8,000+ |
| Impact fees (where applicable) | $0 – $10,000+ (waived in many states) |
| Utility connection fees | $1,000 – $5,000+ (for new water/sewer connections) |
| Architectural plans | $2,000 – $10,000 (separate from permit) |
Fees are typically calculated based on estimated project value. Contact Planning, Building and Code Enforcement — Building Division for exact amounts.
How Long Does It Take?
In San Jose, typical approval time for adu permits is about 6 weeks.
More complex projects requiring structural review or variances may take longer. Simple projects may qualify for expedited or over-the-counter review in some cases.
How to Apply for a ADU Permit in San Jose
- 1 Check requirements: Use our free lookup tool or contact Planning, Building and Code Enforcement — Building Division to confirm your project needs a permit.
- 2 Gather documents: Prepare your application, site plan, construction drawings, and any other required documents.
- 3 Submit online: San Jose accepts applications online at Planning, Building and Code Enforcement — Building Division.
- 4 Pay fees: Pay the applicable permit fees ($750 – $7,500).
- 5 Wait for approval: Your application will be reviewed by San Jose plan reviewers. Typical turnaround is about 6 weeks.
- 6 Begin work: Once approved, post your permit visibly at the job site before starting work.
- 7 Schedule inspections: Call Planning, Building and Code Enforcement — Building Division at (408) 535-3555 to schedule required inspections at each phase of the project.
San Jose Building Department Contact
Required Inspections in San Jose
Most adu projects in San Jose require inspections at each construction stage:
Foundation Inspection, Footing dimensions, depth below frost line, rebar placement, anchor bolt locations, soil bearing conditions, and compliance with structural engineering plans.
Framing Inspection, Wall framing, headers, connections to existing structure (for attached/conversions), fire separation between ADU and main house, egress windows/doors, ceiling height compliance, and overall structural integrity per approved plans.
Rough-In Trade Inspections, Electrical: circuits, GFCI/AFCI, panel capacity. Plumbing: DWV routing, supply lines, water heater, fixture connections. Mechanical: HVAC ductwork, ventilation, combustion air. All work must be visible.
Final Inspection, All fixtures operational, smoke and CO detectors, GFCI tested, kitchen appliances connected, egress windows functional, address numbers posted, and overall compliance with approved plans. Certificate of occupancy issued upon passing.
Schedule inspections with Planning, Building and Code Enforcement — Building Division at (408) 535-3555 at least 24–48 hours in advance.
Frequently Asked Questions
Whether you need a permit depends on the size and scope of your adu project. In San Jose, some smaller projects are exempt while larger ones require a permit. Use our free lookup tool to check your specific situation.
Permit fees for adu projects in San Jose typically range from $750 – $7,500. Fees are usually based on the estimated project value.
Typical approval time in San Jose is about 6 weeks. Complex projects requiring structural review may take longer.
In most cases, homeowners in San Jose can pull permits and perform work on their own primary residence as an owner-builder. You're still responsible for meeting all code requirements and passing inspections.
Working without a required permit in San Jose can result in fines, stop-work orders, required removal of completed work, and complications when selling your home.
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Free Permit Lookup →Other Permit Guides for San Jose, CA
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ADU Permits in Nearby Cities
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See Detailed ADU Rules for San Jose
View all local rules, exemptions, and fee details on the permit page.
ADU Permit Rules →