City Spotlight: Comparing ADU Permit Rules in SF, Oakland, and San Jose

Table of Contents

1. What is an ADU?

2. Benefits of Building a Permitted ADU

3. Comparing ADU Permit Rules in SF, Oakland, and San Jose

4. Key Differences

5. Permit Process in Each City

6. Common ADU Mistakes to Avoid

7. FAQ

What is an ADU?

An Accessory Dwelling Unit (ADU) is a secondary residential unit built on the same lot as a primary home. These units—also called secondary suites, granny flats, in-law units, or backyard homes—can be detached, attached, or converted from an existing space like a garage.

Thanks to California’s pro-housing laws, cities like San Francisco, Oakland, and San Jose have streamlined ADU permitting. However, local zoning rules still vary, making it essential for homeowners to understand city-specific differences.

✅ Benefits of Building a Permitted ADU

Building a permitted ADU in the Bay Area offers long-term financial, personal, and community benefits:

📈 Increase Property Value
A legal ADU significantly boosts home resale and equity.
💸 Earn Rental Income
Rent out your ADU for consistent cash flow, legally.
🏡 Flexible Living Arrangements
Perfect for multigenerational households, live-in caregivers, or aging in place.
⚖️ Stay Legal & Compliant
Avoid fines, red tags, and potential demolition by following local permitting rules.

🏙️ Comparing ADU Permit Rules in SF, Oakland, and San Jose

Below is a side-by-side breakdown of how ADU rules differ in San Francisco, Oakland, and San Jose:

Feature	San Francisco	Oakland	San Jose
Max ADU Size	Up to 1,200 sq. ft.	Up to 1,200 sq. ft.	Up to 1,200 sq. ft.
Setback Requirements	4 ft. rear/side for detached units	4 ft. rear/side	4 ft. rear/side (less in some zones)
Height Limit	16–20 ft. depending on lot configuration	16–20 ft.	Up to 24 ft. in some zones
Owner-Occupancy	Not required for ADUs (until 2025)	Not required	Not required for ADUs
Parking Requirements	Waived if near transit	Waived if near transit	Waived if within ½ mile of public transit
Permit Timeline	4–6 months (60-day law applies)	3–5 months	2–4 months with fast-track options
JADU Allowed?	Yes (must be within existing structure)	Yes	Yes

Key Differences:

San Francisco is stricter on design and historic district approvals, especially in older neighborhoods.
Oakland offers generous incentives for converting existing garages and basements.
San Jose has the fastest permitting system and offers pre-approved ADU plans to speed up the process.

🔨 Permit Process in Each City

San Francisco ADU Permit Process

Additional scrutiny if located in historic or RH zoning.
Must consult the Planning Department before building.
More complex plan review process due to design overlays.

Oakland ADU Permit Process

Streamlined via the Planning & Building Department.
Garage conversions and basement units are especially favored.
Easier if you’re not in hillside zones.

San Jose ADU Permit Process

Offers pre-approved ADU plans.
Online permit submittal and virtual inspections.
Fast-track options for detached units under 800 sq. ft.

⚠️ Common ADU Mistakes to Avoid

Ignoring city-specific zoning overlays or design requirements.

Building without permits, risking red-tag violations.
Misunderstanding lot size restrictions or easements.
Overlooking utility hookup or fire safety rules.

Learn more about How to Get an ADU Permit in California

FAQ

Can I build more than one ADU in these cities?

Yes. California ADU law allows one ADU and one Junior ADU (JADU) per residential lot. All three cities follow this.

Do I need to notify neighbors before building?

Usually not unless a variance is required. Always check with the city’s Planning Department.

Can I build an ADU on a multifamily property?

Yes. All three cities allow multiple ADUs on multifamily lots under state law, often in converted non-livable areas.

Do these cities have impact fees?

Impact fees are waived for units under 750 sq. ft. in all three cities.

Can I rent out my ADU short-term?

No. Short-term rentals (e.g., Airbnb) are typically not allowed in ADUs unless you follow additional city-specific requirements (and most cities restrict them heavily).