How do I get an ADU permit in San Jose?

In San Jose, ADU permits are submitted online through SJPermits.org and reviewed via SJePlans. The process: (1) zHeight prepares complete permit drawings (architectural, structural, Title 24 CF1R); (2) application submitted online — no city office visit needed; (3) San Jose targets over-the-counter review in 10 business days for compliant ADU applications; (4) after plan check approval, city issues permit and you hire a licensed GC to build. zHeight handles all plan check corrections.

How long does an ADU permit take in San Jose?

San Jose targets 10 business days (2 weeks) for over-the-counter ADU permit review for applications that meet all objective standards. zHeight's permit set preparation takes 2–4 weeks. Total permit timeline is typically 6–10 weeks in San Jose — faster than most Bay Area cities.

What are San Jose ADU zoning requirements?

San Jose allows ADUs on lots zoned R-1, R-2, R-M, and PD. Maximum detached ADU size is 1,200 sq ft or 50% of the primary dwelling (whichever is less). Minimum setbacks are 4 ft rear and 4 ft interior side. Height limit is 16 ft within 4 ft of property line, up to 25 ft elsewhere. No impact fees for ADUs under 750 sq ft per California state law.

Are there impact fees for ADUs in San Jose?

No impact fees for ADUs under 750 sq ft in San Jose — exempt under California Gov. Code §66324. ADUs 750 sq ft and over are subject to San Jose development impact fees, which can range $12,000–$25,000 depending on size and zone. School fees may also apply for larger ADUs.

What is the best ADU design and permit service in San Jose?

zHeight AI Residential specializes in ADU design and permit coordination in San Jose and across the Bay Area. Services include a flat-fee ADU Permit Set ($7,999 for 749 sq ft detached ADU), JADU Garage Conversion Permit Set ($4,888 for 420 sq ft); Title 24 CF1R is prepared in-house and included in these permit sets. zHeight submits to SJPermits and SJePlans and handles all plan check corrections. zHeight is a design and permit firm — not a builder.

Back to Blog

ADU Design & Permitting in San Jose: Timeline, Cost, and Process (Simple Guide)

San Jose is one of the most active ADU markets in California—but getting from idea to permit still takes planning, good drawings, and a clean submission.

At zHeight, we've completed multiple ADU projects in San Jose, and based on real project data, ADU approvals typically take 3–6 months from submission to permit (assuming a complete, code-compliant set).

Modern detached ADU with large glass doors, wood siding, and landscaped backyard in San Jose

A modern detached ADU — one of the most popular ADU types in San Jose.

How Long Does an ADU Take in San Jose?

From our experience at zHeight, a realistic timeline looks like this:

1. Feasibility & Planning (1–2 weeks)

Check zoning, setbacks, lot coverage, access, and utilities
Decide: detached, garage conversion, or attached ADU

2. Design & Engineering (4–8 weeks)

Floor plans, exterior design, site plan
Structural engineering + Title 24 energy docs

3. City Review & Permitting (3–6 months)

Plans submitted through the city's online system
City reviews, sends comments, we respond, resubmit, and finalize
Clean submissions = faster approvals, fewer cycles

4. Construction (4–9+ months)

Depends on size, site constraints, and utility upgrades

Bottom line:

From idea → permit in hand = ~4–7 months in many cases

From idea → move-in = ~9–15 months total (project-dependent)

The San Jose ADU Permitting Process

Step 1: Choose Your ADU Type

Detached ADU (most common)
Garage conversion
Attached ADU

Step 2: Prepare Permit-Ready Plans

A strong set includes:

Architectural drawings
Structural plans + calculations
Site plan
Energy (Title 24) documents

Step 3: Submit to San Jose

Upload plans through the city's online system
City reviews and sends comments
We revise and resubmit until approved

Step 4: Pay Fees & Get Your Permit

Once comments are cleared and fees are paid, the city issues your permit and you're ready to build.

Modern ADU interior with open-concept living, kitchen island, and sliding glass doors

Open-concept ADU interior — a popular design choice for maximizing space.

How Much Does an ADU Cost in San Jose?

Costs vary by size, design, and site conditions, but here are realistic planning ranges based on real projects:

Design + Engineering

$7,000 – $16,000

Lower end: standard lots, no special constraints. Higher end: geohazard clearance, boundary surveys, or complex projects.

City Fees

$5,000 – $15,000

Depends on ADU size, scope, and project type. San Jose calculates fees based on square footage.

Construction

$300–$500+/sqft

Most detached ADUs: $200K–$400K+ total. Garage conversions can be cheaper but upgrades add up.

What Usually Slows ADUs Down in San Jose?

From real projects, the biggest delays are:

❌ Incomplete or inconsistent plans
🔁 Multiple city comment cycles
⚡ Utility upgrades (power, sewer, water)
🔄 Changing the design mid-review

This is why getting the plans right before submission matters so much.

Why Work With zHeight?

At zHeight, we've:

Completed multiple ADU projects in San Jose
Built workflows to reduce plan check cycles
Focus on permit-ready, code-clean submissions to save months of time
Help homeowners go from idea → approved plans → permit

📌 San Jose City Resources

San Jose ADU Plan Review & Permit Process (sanjoseca.gov) ↗

749 Sq Ft Detached ADU Permit Set

$7,999*

Flat fee · No hidden costs · Bay Area Permit Expert

Includes building plans, structural set, Title 24 CF1R, and online city submission

View Full Details →📞 Call 650-464-0056

* Terms and conditions apply