Article XIII-A of the California Constitution (Proposition 13) requires that real property be reappraised whenever a change in ownership occurs. When a transfer occurs, the Assessor receives a copy of the deed and an appraisal is made to determine the new market value of the property. The property owner is then notified of the new assessment, and has the right to appeal the value if he does not agree with it.
The amount of the supplemental assessment is the difference between the prior assessed value and the new assessment on the property. This value is pro rated, based on the number of months remaining in the fiscal year. Thereafter the new owner pays the full tax based on the new assessed value. The previous owner is liable for the tax due up to the date of sale; the new owner is responsible for the tax after the date of sale.