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Sonoma County, CA Building Setbacks & Zoning: Setback Rules (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

Key Facts

R1 front yard
Min. 20 ft; no structure within 45 ft of road centerline (Sec. 26-20-030(f))
R1 side yard
Min. 5 ft (equals front yard where it abuts a street)
R1 rear yard
Min. 20 ft
Projections
Eaves/bay windows 2 ft; uncovered porches 6 ft front/rear, 3 ft side
Varies by zone
AR, RR and resource districts have different/larger setbacks
Ag buffer
Parcels adjoining AR/ag land subject to buffer (Sec. 26-88-040)

Summary

Building setbacks in unincorporated Sonoma County are set by each zoning district in Chapter 26. In the R1 Low Density Residential district, the front yard must be at least 20 feet (and no structure closer than 45 feet to a road centerline), side yards at least 5 feet, and rear yards at least 20 feet. Other districts have different yards.

City-specific rules exist: Petaluma, and Santa Rosa have their own setback rules rules that differ from Sonoma County's county-level regulations. If you live in one of those cities, check the city-specific page instead.

Sec. 26-20-030. - Permitted residential density and development criteria.

(f) Yard Requirements.

(1) Front Yard. Not less than twenty feet (20); provided, however, that no structure shall be located closer than forty-five feet (45) to the centerline of any public road, street or highway.

(2) Side Yard. Not less than five feet (5) except where the side yard abuts a street in which case such yard shall be the same as the front yard.

(3) Rear Yard. Not less than twenty feet (20).

Source: Sonoma County Zoning Code Ch. 26, §26-20-030 (Municode)View official code

Full Breakdown

Sonoma County's Zoning Code (Chapter 26) sets minimum yard (setback) requirements separately for each zoning district, so the exact numbers depend on your parcel's zone. For the R1 Low Density Residential district, Section 26-20-030(f) requires a front yard of not less than twenty feet (20'), provided that no structure may be located closer than forty-five feet (45') to the centerline of any public road, street or highway; side yards of not less than five feet (5'), except where a side yard abuts a street, in which case it must equal the front yard; and a rear yard of not less than twenty feet (20').

Garages and carports with openings facing the street must be at least 20 feet from the exterior property line, though this can be reduced to as little as 10 feet where most of the block is already improved. Limited architectural projections are allowed: cornices, eaves, bay windows and similar features may extend 2 feet into a required yard, and uncovered porches may extend 6 feet into a front or rear yard and 3 feet into a side yard. Accessory buildings may be placed in required yards on the rear half of the lot subject to limits.

Agricultural, rural-residential and resource districts have their own (often larger) setbacks, and parcels adjoining AR or agricultural land are subject to additional buffer requirements. Always confirm your zoning district and any recorded setback lines with Permit Sonoma.

Violations & Fines

Building within a required yard, too close to a road centerline, or in violation of recorded setback lines can result in a code-enforcement notice, denial or revocation of permits, fines, and an order to remove or relocate the structure. A variance is required to legally reduce a required setback.

Frequently Asked Questions

What are the setbacks for a house in unincorporated Sonoma County?
It depends on your zoning district. In the common R1 Low Density Residential district (Section 26-20-030(f)), the front yard must be at least 20 feet (and nothing closer than 45 feet to a road centerline), side yards at least 5 feet, and the rear yard at least 20 feet. Agricultural and rural-residential zones have different, often larger, setbacks - confirm your zone with Permit Sonoma.
Can eaves or a porch extend into the setback?
Yes, within limits. In R1, cornices, eaves, bay windows and similar architectural features may project up to 2 feet into a required yard, and uncovered porches, fire escapes or landings may extend 6 feet into a front or rear yard and 3 feet into a side yard. The projection generally cannot occupy more than one-third of the wall length.

Sources & Official References

Other rules in Sonoma County

All Sonoma County rules

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