Hi Alshesa. This may be a case of Supplemental Taxes.
A law was enacted to require the assessor to appraise property on the date a change in ownership occurs or new construction is completed. Taxes are computed from the 1st of the month following the change to the end of the fiscal year. In most cases, this assessment results in one or possibly two supplemental tax bills being sent to the property owner in addition to the regular secured property tax bill that is mailed annually.
The Assessor appraises the property to determine the new base year value as of the date of the change of ownership or completion of new construction. The Assessor then calculates the difference between the new base year value and the existing roll value. The result is the new Supplemental Assessment. The Assessor will send you a "NOTICE OF SUPPLEMENTAL ASSESSMENT AND IMPENDING TAX BILL".
This reassessment usually results in an increase in property value, in which case your supplemental taxes will be calculated by the Auditor-Controller based on the change in value, and one or possibly two supplemental tax bills will be created and mailed to you by the Tax Collector. However, in some instances the reassessment results in a reduction in value, in which case a refund will be prepared by the Auditor-Controller and mailed to you. A reduction in value WILL NOT reduce the amount due on the annual tax bill. The annual tax bill must be paid in the amount originally billed.
Hope this helps.