Real Property Assessments
The California Constitution requires that all property be taxed, unless otherwise exempted under the California Constitution or United States Constitution. Article XIII-A of the California Constitution requires that real property be reappraised only when such property undergoes a change in ownership or has new construction (per Proposition 13).
The assessment roll and tax bill show land values and improvement values. "Improvements" include buildings or anything of a structural nature (such as swimming pools, paving, etc.). When you have an "improvement" value, it doesn't usually mean that you have recently "improved" your property.
Regular tax roll assessments are made for a Fiscal Year that runs from July 1 to June 30 the following year. Although the two installments are paid in different calendar years, the annual tax bill is for this time period.
The date on which taxes become a lien on the property, referred to as the Lien Date, is the January 1st of the calender year that the fiscal year starts. Therefore, each assessment for any fiscal year reflects the property, any improvements, and any ownership activities that have occurred up to January 1st of that year.
Example: Fiscal Year 2013-2014 runs from July 1, 2013 to June 30, 2014. The tax bill for this fiscal year is mailed out near the end of year 2013 with the first installment due November 1, 2013 and the second installment due March 1, 2014. The Lien Date is January 1, 2013, therefore the assessment on this tax bill reflects the property as it stood, and any ownership interests in it, up to January 1, 2013.
Real Property Supplemental Assessment
A Supplemental Assessment is designed to pick up changes in assessed value, either increases or decreases, that occur in the middle of a fiscal year. Taxes based on these value changes are prorated from the time of the change to the end of the fiscal year.
As the regular tax roll assessment does not reflect any change in the value of a property caused by any activity after January 1st. The Supplemental Assessment is this change in value and produces a Supplemental Tax Bill for increases and a refund for reductions.
The sum of the assessed value on the regular tax roll and the Supplemental Roll equals the total assessed value for the parcel.
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