Since July of 1983, whenever there is a change in ownership or completion of a new construction, the Assessor shall reappraise the property at its full cash value (unless there is a qualifying exclusion or exemption from reassessment). The appraised value then becomes the new base year value of the property.
The Assessor then makes a supplemental assessment which reflects the difference between the prior assessed value and the new assessed value. The value difference is prorated based on the number of months remaining in the fiscal year ending June 30. A supplemental assessment is in addition to and separate from the regular/annual tax bill.