Sonoma County, California Building Permit Guide

Permit Sonoma reviews, permits and inspects virtually all land development and construction in the unincorporated area of Sonoma County, outside the nine incorporated cities. The Permit Center is at 2550 Ventura Avenue, Santa Rosa, CA 95403, (707) 565-1900. In-person and phone hours are Monday, Tuesday and Thursday 8:00 AM - 4:00 PM and Wednesday 10:30 AM - 4:00 PM; the center is closed on Fridays. Remote queuing lets customers join the line or book appointments.

This guide covers unincorporated Sonoma County and Santa Rosa, the county seat. Fees for Fiscal Year 2026-2027 were set by Ordinance 6554 (adopted April 14, 2026, effective July 1, 2026); this guide gives no fee amounts, so use Permit Sonoma’s published fee schedules.

Who handles permitting in Sonoma County?

Census estimates list nine incorporated cities and towns, which run their own permitting: Santa Rosa, Petaluma, Rohnert Park, Windsor, Healdsburg, Sonoma, Cloverdale, Sebastopol and Cotati. Elsewhere, Permit Sonoma handles building, septic, wells and the right of way.

Septic systems and wells in Sonoma County

Septic, water well and graywater permits are issued by Permit Sonoma’s Well & Septic Division, not a separate health department. Permits to drill, abandon or deepen wells can only be issued to licensed C-57 well drilling contractors. Well and septic applications received since May 17, 2023 are valid for one year; the County’s COVID-era two-year extension no longer applies.

Sonoma County permit costs and fees

Residential plan check is valuation-based. What a building permit costs also depends on whether the structure is served by well and septic or by sewer and water; whether an encroachment permit, fire fees or drainage review are needed; and on district-based school and traffic mitigation fees. An Affordable Housing fee may apply to new residential and non-residential square footage.

Encroachment permits in Sonoma County

Placing or building anything in, under or over the public right of way in unincorporated Sonoma County needs an encroachment permit from Permit Sonoma: driveway entrance upgrades, dumpsters, fencing, utility work and trenching, for example.

How to get a building permit in Sonoma County

A building permit carries a validity period and can expire if work does not start or stalls between inspections; confirm the expiry with Permit Sonoma on phased or delayed work. Permit validity in California

Inspections in Sonoma County

The inspection request tool is available 24 hours a day; requests must be made before midnight for a next-business-day inspection, although next-day slots may not be available. As of September 02, 2026, Permit Sonoma reported an 8-9 day delay in scheduling building inspections. When the next opening is more than seven days away, the Selectron phone system cannot take the request, so book on the Permits Online portal, which needs no account. VuSpex video inspections are being enabled for water heaters, furnaces, solar and energy storage.

Building permits in Santa Rosa

The City of Santa Rosa’s Building Division takes questions and appointment requests at (707) 543-3200. Planning entitlements such as Design Review or a Conditional Use Permit must be approved before the building permit application unless concurrent review is approved. Since July 6, 2026 the City has used an enhanced Accela Citizen Access portal to apply, upload plans, check status, schedule inspections and pay fees.

Official Sonoma County permitting resources

These are the primary sources behind this guide. Codes, fee schedules and procedures change — confirm the position for your filing date.

• Permit Sonoma
• Permit Sonoma business hours
• Building inspection delay notice
• Permit Sonoma fee schedules
• Well and septic permits
• Encroachment permits
• Santa Rosa Building Division

Frequently asked questions

Is the Permit Sonoma office open on Fridays?

No. The Business Hours page lists Monday, Tuesday and Thursday 8:00 AM - 4:00 PM and Wednesday 10:30 AM - 4:00 PM, with the center closed on Fridays.

Who issues septic and well permits in Sonoma County?

Permit Sonoma’s Well & Septic Division. Well permits can only be issued to licensed C-57 well drilling contractors.

Why can’t I book my inspection by phone?

When the next opening is more than seven days away, the Selectron phone system cannot take the request; book on the Permits Online portal instead.

Simplify Sonoma County permitting with Alliance Permitting

• Check whether the parcel is in a city or on county land, and which county offices beyond Building must sign off
• Line up septic, well, encroachment and fire approvals so they do not hold up the building permit
• File in the county portal, track review rounds and book inspections against the county’s cut-off times

Alliance Permitting is a permit documentation and submission company in California. We prepare your paperwork, file it correctly and coordinate with the permitting authority through issuance. We are not a contractor and we do not perform licensed plan review or inspections; that work stays with your licensed team and the jurisdiction.

This guide is provided by Alliance Permitting for general information about Sonoma County permitting. Requirements, fees, and procedures change; confirm details with the permitting authority before relying on them.