Understanding Supplemental Property Taxes in California

The Supplemental Real Property Tax Law was signed by the Governor in July of 1983 as part of an effort to aid California's schools. If you buy new property or complete new construction, you will be required to pay a supplemental property tax which becomes a lien against your property as of the date of ownership change or the date of completion of new construction.

When and how will you be billed? Timing is unpredictable — you could be billed in as few as three weeks or it could take over six months, depending on the workload of the County Assessor, County Controller/Auditor, and County Tax Collector. The assessor will appraise your property, advise you of the new supplemental assessment amount, and inform you of your right to file an Assessment Appeal. You may also apply for a Homeowner's Exemption at this time.

How is the amount determined? The total supplemental assessment is prorated based on the number of months remaining until the end of the tax year (June 30). The supplemental tax becomes effective on the first day of the month following the month in which the change of ownership occurred. Proration factors range from 92¢ on the dollar (effective August 1) down to 8¢ (effective June 1). For example: if supplemental taxes on your home would be $1,000 for a full year and the change of ownership took place September 15 (effective date October 1), the proration factor is .75, making your supplemental tax $750.

Can you pay in installments? Yes — all supplemental taxes on the secure roll are payable in two equal installments. If the bill is mailed July through October, the first installment becomes delinquent December 10 and the second installment becomes delinquent April 10 of the next year. If mailed November through June, the first installment becomes delinquent on the last day of the month following the mailing, and the second installment becomes delinquent on the last day of the fourth month after the first installment's delinquency date.

Important: unlike regular annual taxes, supplemental tax is NOT prorated in escrow. It is a one-time tax entirely the obligation of the property owner, dating from the date of ownership until the end of the tax year on June 30. Team Goeglein at Fidelity National Title ensures buyers understand supplemental tax obligations on every South Bay and Westside LA transaction.