San Jose ADU Permits & Requirements
Fees $500–$5,000 · 4–12 weeks timeline · Up to 1,200 sf
Quick Answer
San Jose ADUs: $200K–$400K
Permits: $500–$5,000 · Updated April 2026
Permit Fees Breakdown
| Fee Type | Cost |
|---|---|
| Building Permit | $500–$3,000 |
| Plan Review | $200–$1,000 |
| School Impact Fee | Waived for ADUs under 750 sf |
| Utility Connections | $500–$2,500 |
Permit Process Timeline
ADU Ally Pre-Check
1–2 weeksUse San Jose's ADU Ally program for free feasibility check
Plan Preparation
2–4 weeksArchitectural plans (or use pre-approved plans from ADU Ally)
Permit Review
4–8 weeksCity review — fast-tracked for pre-approved plan sets
Construction
4–8 monthsBuild phase with required inspections
Final Inspection & CO
1–2 weeksFinal inspection and Certificate of Occupancy
Track Every Dollar of Your ADU Build
TerraLine is the construction finance cockpit that shows your loan balance, budget burn, and forecast at completion — all on one screen. No more spreadsheets.
Zoning & Requirements
Max ADU Size
1,200 sf
Height Limit
16 ft (detached)
Setbacks
4 ft side/rear (detached)
Parking
None required (CA law)
Key Regulations
- California AB 68/SB 13 allows ADUs by right on most residential lots
- Max ADU size: 1,200 sf for detached; 50% of primary for attached
- Both an ADU and a JADU allowed on the same lot — maximize rental income
- Impact fees waived for ADUs under 750 sf statewide
- No parking required per California state law
- San Jose ADU Ally program provides free pre-approved plans — saves $5K–$15K in design costs
Climate & Construction Notes
San Jose's mild Mediterranean climate is ideal for ADU construction year-round. Seismic design requirements add to cost but are well-established in local building practices.
Frequently Asked Questions
How long does it take to get an ADU permit in San Jose?
The typical permit timeline is 4–12 weeks from application to approval. Total project time including design and construction is usually 6–12 months.
What types of ADUs are allowed in San Jose?
San Jose allows detached, attached, garage conversion, jadu. Maximum size is 1,200 sf with a height limit of 16 ft (detached).
Do I need to live on the property to build an ADU in San Jose?
JADU only (owner must occupy primary or JADU). Check with San Jose's planning department for the most current requirements.
More San Jose ADU Resources
Ready to Start Your ADU Project?
Join hundreds of homeowners who used our guides to navigate their ADU build successfully.
✓ Free comprehensive guide ✓ Vetted contractor list ✓ No credit card needed