Quick Answer: The ADU permit process in San Jose takes 4–8 weeks for standard ADUs and 2–4 weeks for pre-approved ADU plans. Steps: pre-application, plan submittal, plan check, permit issuance, inspections, final approval. ADU permit fees in San Jose run $3,000–$8,000 depending on size and type.
ADU Permit Process in San Jose 2025
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Getting an ADU permit in San Jose is now faster than ever, thanks to California’s 2020 ADU reform laws (SB 9, AB 68, AB 3182) that streamlined the process. Here’s a complete step-by-step guide to the San Jose ADU permit process for 2025.
Step 1: Pre-Application Research
Before submitting plans, determine: (1) What type of ADU you can build (attached, detached, garage conversion, JADU); (2) Maximum size allowed (San Jose allows up to 1,200 sq ft for detached ADUs, 50% of primary dwelling size for attached); (3) Setback requirements (4 ft from side/rear for detached); (4) Height limits (16 ft for single-story, 24 ft for two-story in some zones).
Step 2: Hire a Designer or Use Pre-Approved Plans
San Jose offers a Pre-Approved ADU Plans Program — select from 14 pre-approved ADU designs (400–1,200 sq ft) that skip the full plan check process. Using a pre-approved plan can cut 4–8 weeks from the permit timeline. Alternatively, hire an architect to design custom plans ($5,000–$15,000).
Step 3: Submit Plans to San Jose DSP
Submit your ADU permit application online through San Jose’s Development Services Portal (DSP) at sjpermits.org. Upload: site plan, floor plan, elevations, title 24 energy calculations (if new construction), and structural calculations. Pay the plan check fee at submission ($1,500–$4,000 depending on project value).
Step 4: Plan Check (2–8 Weeks)
San Jose’s plan check team reviews your plans for zoning compliance, building code compliance, and structural adequacy. California law requires ADU applications to be approved or denied within 60 days of submission. For pre-approved plans, San Jose must approve within 30 days. Expect 1–2 rounds of corrections (“plan check comments”) before approval.
Step 5: Permit Issuance & Construction
Once plans are approved, pay the building permit fee ($1,500–$4,000) and receive your permit. Construction can begin immediately. Typical ADU construction timeline: 3–6 months for detached ADUs, 2–4 months for garage conversions.
Step 6: Inspections
Schedule required inspections through San Jose DSP: foundation, framing, rough electrical/plumbing/HVAC, insulation, drywall, and final inspection. Schedule each inspection online — San Jose typically provides next-day inspection availability.
ADU Permit Costs in San Jose 2025
| Fee Type | Estimated Cost |
|---|---|
| Plan check fee | $1,500–$4,000 |
| Building permit fee | $1,500–$4,000 |
| Utilities connection fees | $3,000–$8,000 |
| School impact fee | $3.79–$4.25/sq ft |
| Total permit costs | $8,000–$20,000 |
Quartz Construction manages the complete ADU permit and construction process in San Jose. CSLB #1003436 | BBB A+ | 4.9⭐ (65+ reviews). Call (650) 749-7436 for a free ADU site assessment.
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