Zoning & Size Limits
| Requirement | Berkeley, CA | San Jose, CA |
|---|
| Allowed Zones | Any lot zoned to allow residential use with an existing or p | All residential zones (R-1, R-2, R-M, R-MH) |
| Max Size (Detached) | 1,200 sq ft outside the Hillside Overlay; 850 sq ft (studio/1-bedroom) or 1,000 sq ft (2+ bedrooms) within the Hillside Overlay | 1,200 sq ft |
| Max Size (Attached) | Same limits as detached (1,200 sq ft outside Hillside Overlay); conversions of existing space have no size cap | 1,200 sq ft or 50% of primary dwelling |
| Max Height | Detached new construction: 25 ft (20 ft within Hil | 25 ft for detached |
| Parking Required | None required for ADUs or JADUs; displaced garage parking do | No parking required |
| Owner Occupancy | Not required for ADUs. JADUs with separate sanitation facili | Not required |
Setback Requirements
| Setback | Berkeley, CA | San Jose, CA |
|---|
| Rear Setback | 4 ft minimum | 4 ft |
| Side Setback | 4 ft minimum (interior or street side); architectural features may project 2 ft if 2 ft remains to the property line | 4 ft |
| Front Setback | ADUs may be placed within the front setback | Per underlying zone |
Permits & Timeline
| Detail | Berkeley, CA | San Jose, CA |
|---|
| Permit Timeline | 60-day ministerial review; deemed approved if the city fails to act within 60 days (SB 543, eff. Jan 1, 2026) | 60 days |
| Permit Fees | $250 zoning plan check + $500 neighbor noticing fee at submittal + $250 address assignment; building permit fees based on project valuation (city fee estimator tool available) | $4,000-$14,000 |
| Impact Fees | Land Use Planning assesses no impact fees. Berkeley Unified | Waived for units under 750 sq ft |
| Pre-Approved Plans | Yes — the city points applicants to pre-approved A | Limited pre-approved options available |
Construction Costs
| Cost | Berkeley, CA | San Jose, CA |
|---|
| Avg Build Cost | $250,000-$500,000 | $180,000-$400,000 |
| Cost Per Sq Ft | $400-$700 | $250-$450 |
| Garage Conversion | $120,000-$250,000 | $100,000-$220,000 |
| Prefab ADU | $250,000-$320,000 | $130,000-$300,000 |
Rental Income Potential
| Rental | Berkeley, CA | San Jose, CA |
|---|
| 1BR Avg Rent | $2,300-$2,900/mo | $2,000-$2,800/mo |
| 2BR Avg Rent | $3,000-$3,900/mo | $2,500-$3,500/mo |
| Short-Term Rentals | No — recorded deed restriction prohibits short-term rental o | Restricted; requires transient occupancy tax registration |
| Est. ROI | 4-7% annual return | 5-9% annual return |
Which City Is Better for ADUs?
Berkeley scores 9/10 while San Jose scores 8/10 on our ADU-friendliness index.
Berkeley edges ahead overall. Both cities offer viable ADU development opportunities — the best choice depends on your specific property, budget, and goals.
Finance Your ADU Project
Most ADU projects are funded through HELOCs, construction loans, or cash-out refinancing. Compare rates from top lenders.
Some links on this page are affiliate links. We may earn a commission at no extra cost to you. Learn more
Get Quotes in Your City
Connect with licensed ADU contractors and get free quotes for your project.