Sonoma County, CA Sign Regulations: Political Signs (2026)

Sonoma County's Registrar of Voters campaign guidance states that, in the unincorporated county, campaign signs shall not be erected earlier than 90 days prior to the election and must be removed entirely within 20 days of the close of the campaign. The guidance directs sign-makers to Article 84 (Sign Regulations) of the Sonoma County Zoning Ordinance (Chapter 26) for applicable design standards and notes that a zoning permit may be required through Permit Sonoma (PRMD) for certain signs. Signs supporting a candidate who advances from a primary may be retained through the general election if properly maintained. Campaign signs must be placed on private property only, with the owner's permission, and may not be posted on public property, utility poles, or within highway rights-of-way. Independently, California's Outdoor Advertising Act (Business and Professions Code Sec. 5405.3) governs temporary political signs along state highways: such signs may be no larger than 32 square feet, may be placed no sooner than 90 days before the election, must be removed within 10 days after the election, and require an on-file statement of responsibility for their removal. Signs are also barred within highway rights-of-way and within 660 feet of landscaped freeways where visible. Property owners should follow whichever timeline is stricter and avoid public rights-of-way entirely.