Skip to Content

Unsecured Property Taxes

The Sonoma County Treasurer Tax-Collector is charged with collection of unsecured taxes. Unsecured property taxes are taxes on un-landed property such as:

  • Business Equipment and Leasehold Improvements
  • Mobile homes that are not attached to a foundation 
  • Aircraft and Vessels (including fishing vessels)
  • Cabins on leased or Publicly Owned Property
  • Leased Business Equipment
  • Possessory Interest (lessees of publicly owned properties such as marinas, airports, grazing rights, and housing on publicly owned lands)
  • Unsecured Supplemental (real estate tax billed to a former owner following the close of escrow, for differences in assessed value resulting in an additional tax computed for a prior period of ownership) 

Unsecured taxes are computed by the County Assessor, who determines the value of the property and transmits that information to the County Auditor. The Auditor computes the amount of tax (see Computation of Taxes, above) and transmits that information to the Tax Collector, who prepares the bill for the taxpayer and collects the tax. If you have questions regarding valuation of your unsecured property, please contact the Sonoma County Assessor's Office at (707) 565-1330.

Unsecured Property taxes are levied on property as it exists on January 1st at 12:01 AM. Tax bills are prepared and mailed in July of each year. Unsecured taxes must be paid on or before August 31st unless otherwise stated. The obligation to pay unsecured taxes rests with the assessed owner of record on the lien date (January, 12:01 AM.) The disposal of property AFTER the lien date does not relieve the assessed owner from the obligation to pay unsecured taxes. Delinquent unsecured taxes are subject to collection enforcement. The Tax Collector cannot pro-rate taxes.