What is a supplemental tax?/Why did I receive two supplemental assessments?

A supplemental assessment is created each time property is revalued by the Assessor due to a change in ownership or completion of new construction. The date either of these occurs is called the “date of event.” Supplemental taxes are calculated for the portion of the fiscal year for which the change in value applies. A factor based on the date of event is set by state law and this factor is applied to the tax rate calculation. The Auditor issues refunds when supplemental assessments result in a decreased value.

The value of a supplemental assessment is the difference between the prior and the new assessed values. The taxes are prorated based on the date of event on which the change of ownership occurred or the new construction was completed to the end of the fiscal year on June 30th. Depending on the date of event, either one or two supplemental assessments may be generated. If the event date was between January 1st and June 30th, there are two supplemental assessments because two different tax years are affected. The following show examples of how two assessments might occur. Please remember that taxable property is assessed by the Assessor each year as of the January 1st lien date to generate tax revenue for the fiscal year that begins on the upcoming July 1st.

  • If property was purchased in February, 2011, then one assessment is for the value difference for the remainder of the 2010 to 2010 fiscal year. The other assessment is for the value difference for the 2011 to 2012 fiscal year since the event occurred after the January 1, 2011 lien date for the 2011 to 2012 secured roll. This value difference will not be picked up on the annual secured roll until the January 1, 2012 lien date, which is for the 2012 to 2013 tax roll.
  • Multiple “Supplement Events” occurred (such as a change in ownership followed by completion of new construction or multiple completions of new construction) within a fairly short time span. A separate assessment will be calculated for each Supplemental Event.

Additional Information

For additional information on the assessing of supplemental values, contact the Placer County Assessor. For additional information on paying supplemental taxes, contact the Placer County Treasurer-Tax Collector.

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1. What is a supplemental tax?/Why did I receive two supplemental assessments?
2. How are my taxes calculated?