Annual Report
State of ADU in California: 2026
Aggregated data from 100 California cities. Build costs, permit fees, rental income, and regulatory trends — all from official planning department sources.
Data compiled March 2026. Updated annually.
Cities Tracked
100
across California
Avg Build Cost
$241k
statewide average
Avg Rental/mo
$2,174
estimated monthly
Avg Permit Fees
$11k
mid-range estimate
Regulatory Landscape
How California Cities Approach ADUs
Cities with no owner-occupancy requirement
100 of 100
State law suspended this requirement through 2025; many cities have permanently removed it.
Cities allowing 2+ ADUs per lot
100 of 100
Includes cities permitting both a detached ADU and a JADU on a single lot.
Average max detached ADU size
1,200 sq ft
State law sets a 1,200 sq ft floor — most cities honor exactly this limit.
City with highest allowed ADU size
Los Angeles: 1,200 sq ft
Some cities allow larger ADUs based on lot-size formulas or local ordinances.
Build Costs
Most and Least Expensive Cities
Based on the midpoint of each city's reported build cost range.
Most Affordable
- $85,000 – $190,000
- $90,000 – $195,000
- $90,000 – $200,000
- $90,000 – $200,000
- $100,000 – $220,000
Most Expensive
- $250,000 – $700,000
- $200,000 – $600,000
- $200,000 – $550,000
- $200,000 – $550,000
- $230,000 – $450,000
Geography
Cities Tracked by County
Key Findings: 2026
- ›The statewide average ADU build cost is approximately $241k, up from prior years due to material and labor cost pressures in coastal markets.
- ›100 of 100 tracked cities (100%) have removed or suspended owner-occupancy requirements, making rental-focused ADU investment more accessible.
- ›100 cities allow 2 or more ADUs per lot, meaning a homeowner can potentially build both a detached ADU and a JADU on a single property.
- ›Permit fees range from under $5,000 in smaller inland cities to over $30,000 in some coastal metros — a 6x spread that meaningfully affects project economics.
- ›Impact fee waivers for ADUs under 750 sq ft remain in effect statewide, saving owners an estimated $5,000–$30,000 depending on city.
California ADU Questions Answered
How many cities in California allow ADUs?
All California cities must allow ADUs under state law (AB 68, SB 13, AB 881, and subsequent legislation). ADUByCity tracks detailed regulations for 100 California cities covering the vast majority of the state's population.
What is the average cost to build an ADU in California?
Across 100 California cities, typical ADU build costs range from around $150,000 for modest garage conversions in inland cities to $500,000+ for new detached ADUs in coastal metros. The statewide average sits around $250,000–$350,000 depending on ADU type and location.
Which California cities have changed their ADU rules most recently?
ADU regulations change frequently as cities implement state mandates. All data on ADUByCity is verified against official planning department sources. Each city page shows a last-verified date so you can see how current the information is.
How much rental income can I earn from a California ADU?
California ADU rents vary significantly. Coastal cities average $2,500–$4,500/mo while inland cities typically range $1,200–$2,500/mo. Rental income depends on ADU size, location, quality of finish, and local market conditions.
Methodology: All data is sourced from official city planning department publications, municipal codes, and ADU-specific program pages. Cost ranges represent contractor estimates and publicly available project data for each city. Permit fee ranges are sourced from city fee schedules. Rental estimates reflect local market data. All figures are estimates and may vary based on specific project details. Last updated March 2026.