Sonoma County · ADU permit data · Updated 2026-10-20
6.4months median, application to building permit, 2023–2025
That is about the same as the Bay Area median of 6.0 months. One in four applicants waited more than 10.2 months.
ADUs permitted in 2023–2025, 89 matched on parcel number. Includes time owners spent revising plans.
Source: California HCD Annual Progress Reports, filed by the City of Santa Rosa
Fast quarter, median and slow quarter, in months
Santa Rosa 3.6–10.2 mo
Sonoma County
Bay Area 3.8–10.5 mo
Median Fast quarter to slow quarter
Median wait
Where Santa Rosa sits among 52 ranked cities
Santa Rosa Other ranked cities Bay Area 6.0
Santa Rosa
6.4months
median wait, 2023–2025
State law gives the city 60 days to act once an application is complete. Counted from first submission, this share of ADUs took longer. Ask for the completeness letter, which is due within 15 business days, and keep its date.
Source: HCD Annual Progress Reports, 2023–2025; Gov. Code 66317
Santa Rosa
91%
of matched ADUs
One applicant in four took longer than this. Plan on it if the city sends your plans back for another round of corrections.
Source: HCD Annual Progress Reports, 2023–2025, 75th percentile
Santa Rosa
10.2months
One applicant in four had a building permit within this time from first submission.
Source: HCD Annual Progress Reports, 2023–2025, 25th percentile
Santa Rosa
3.6months
Source: units by calendar year, as reported by the City of Santa Rosa to California HCD
Santa Rosa, units per year
ADU permits a year, 2023–2025 average
ADU permits a year per 1,000 houses, 109 places
Santa Rosa Other Bay Area places
Santa Rosa
79a year
ADU permits, 2023–2025 average
Of every home Santa Rosa permitted in 2023–2025, this share was an ADU.
Source: HCD Annual Progress Reports, 2023–2025
Santa Rosa
13%
Permits a year for every 1,000 detached houses, so small and large cities can be compared.
Source: HCD Annual Progress Reports; DOF housing estimates
Santa Rosa
1.9
rank 71 of 92
Yearly ADU permits in 2023–2025, up 20% from 2019–2021.
Source: HCD Annual Progress Reports
Santa Rosa
+20%
Median time from building permit to certificate of occupancy for ADUs finished in 2023–2025. Add it to the permit wait for a full timeline.
Source: HCD Annual Progress Reports, 2023–2025
Santa Rosa
12.5months
median of 44
One ADU in four took longer than this to reach a certificate of occupancy after the permit.
Source: HCD Annual Progress Reports, 2023–2025, 75th percentile
Santa Rosa
19.8months
Median Fast quarter to slow quarter Bay Area median, 6.0 months Number is the rank out of 52 cities
Every page in Sonoma County: median wait where we can measure it, otherwise ADU permits a year
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Source: Bay Area ADU Permit Clock 2026, our analysis of the California HCD Housing Element Annual Progress Reports (data.ca.gov) filed by the City of Santa Rosa, and DOF housing estimates. Wait times are matched on parcel number and include applicant revision time. The 60-day rule is in Government Code section 66317. How we measured it · See all 109 jurisdictions
For ADUs permitted in 2023–2025, the median time from application to building permit in Santa Rosa was 6.4 months (194 days), based on 89 permits we could match. A quarter took longer than 10.2 months.
Santa Rosa issued 238 ADU building permits in 2023–2025, about 79 a year. ADUs were 13% of all new homes permitted there.
The median time from building permit to certificate of occupancy was 12.5 months for ADUs completed in 2023–2025.