ADU and casita permits in unincorporated Sonoma County, CA

How these numbers are made

Source: Sonoma County Open Data, Sonoma County Construction Permits (Socrata dataset 88ms-k5e7), read 23 Oct 2026. We count permits issued June 2023 through May 2025; denied and withdrawn permits are left out.

Building, solar and demolition permits Permit Sonoma issues for unincorporated Sonoma County only (Sonoma Valley, Guerneville and the Russian River, Glen Ellen, Larkfield-Wikiup, Bodega Bay, Penngrove and other rural areas). Santa Rosa, Petaluma, Rohnert Park, Windsor, Healdsburg, Sonoma, Cotati, Sebastopol and Cloverdale run their own building departments and are not in this file. Encroachment, septic, well, grading and sewer permits are left out.

• The county's file names no contractor, so there are no contractor lists, rankings or firm pages for Sonoma County.
• The county's open file holds only permits started from October 23, 2022 to May 30, 2025 and has not added newer permits since, so these pages end with May 2025. The window starts in June 2023 because permits applied for before the file begins and issued later are missing, which undercounts the first months.
• Finished means the county's status is Finaled. Expired permits lapsed without a final; denied and cancelled permits are not counted. The file has no final date, so we show no time to final.
• Permit Sonoma files most work under two broad types (with or without plan check), so the kind of work is read from the permit description: solar, reroofs, furnaces and heat pumps, water heaters, panels and so on. Permits with no description count as other.
• The file can't reliably tell homes from other property, and it has no declared value on most permits and no ZIP code, so there are no homes figures, costs or ZIP pages.

Counts are permits, not jobs: one job can need several permits. Nobody paid to be on this page and nobody can. Sources and definitions →