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Sonoma County, CA Home Business: Signage Rules (2026)

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

Key Facts

Code section
Sonoma County Zoning Code 26-88-121
Number of signs
One (1) only
Maximum size
2 square feet
Mounting
Attached (not freestanding)
Illumination
Not permitted

Summary

Sonoma County Zoning Code Section 26-88-121 limits a home occupation to one attached, non-illuminated sign no larger than 2 square feet in the unincorporated County. Larger, freestanding, or illuminated business signs are not allowed for home occupations.

City-specific rules exist: Petaluma, and Santa Rosa have their own signage 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.

A home occupation shall be limited to one (1) attached, non-illuminated, two (2) square-foot sign. The home occupation shall not require any change of the residential character or the outside appearance of the dwelling, either by the use of colors, materials, lighting, noise, or signs other than signage permitted by this section.

Full Breakdown

Signage for a home occupation in unincorporated Sonoma County is tightly restricted under Section 26-88-121 of the County Zoning Code. The rule limits a home occupation to 'one (1) attached, non-illuminated, two (2) square-foot sign.' That means the sign must be attached to the structure (not freestanding or pole-mounted), cannot be lit, and cannot exceed 2 square feet in area. This is consistent with the broader home-occupation standard that the business must not change the residential character or outside appearance of the dwelling, and must not create offsite glare or light. Any larger sign, an illuminated sign, an additional sign, or off-premises advertising would exceed what the home-occupation provision allows and would require a different land-use approval. Because the home occupation cannot alter the dwelling's exterior appearance, signage is intended to be minimal and unobtrusive. Operators should treat the single 2-square-foot attached sign as the maximum permitted identification for the business at the residence.

Violations & Fines

Posting a sign larger than 2 square feet, an illuminated sign, or more than one sign for a home occupation violates Zoning Code Section 26-88-121 and the no-exterior-change standard. Permit Sonoma code enforcement can require removal of non-compliant signs and may treat repeated violations as zoning nuisances subject to abatement.

Frequently Asked Questions

Can I put a lit business sign in my yard for a home occupation?
No. Section 26-88-121 allows only one attached, non-illuminated sign of 2 square feet or less. Freestanding yard signs and illuminated signs are not permitted for a home occupation in the unincorporated County.
How big can my home business sign be?
No larger than 2 square feet, and there can be only one such sign, attached to the structure and not illuminated, per Sonoma County Zoning Code Section 26-88-121.

Sources & Official References

Other rules in Sonoma County

All Sonoma County rules

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