Supplemental Assessments

A supplemental tax bill is generated whenever a property is reassessed due to a change in ownership (a sale, transfer, or transfer of fractional interest), or undergoes new construction. The supplemental tax bill reflects any increase or decrease in property tax generated by the supplemental event.

It is important to understand that supplemental tax bills are in addition to the regular annual tax bill and are mailed directly to the owner of the property. These bills are the responsibility of the owner even if the property taxes are normally paid by a lender through an impound account. You may need to discuss the matter carefully with your lender. In any case, do not presume that your lender will automatically pay these types of bills.

A History of Supplemental Assessments

On July 1, 1983, Senate Bill 813 amended the state Revenue and Taxation Code to create what are known as "Supplemental Assessments." This new law changed the manner in which changes in assessed value were billed by requiring that any increase or decrease in taxes due to a change in ownership or completed new construction became effective as of the first day of the month following the date of change in ownership or the date new construction was completed rather than on the next annual tax bill. Supplemental assessments result in tax bills that are "in addition to" (that is, supplemental to) the annual property tax bill sent to property owners in October. Changes in ownership or completed new construction that trigger supplemental assessments are referred to as "supplemental events."

Important

Depending on the date of the supplemental event, either one or two supplemental tax bills will be produced. If the date is:

• June 1 to December 31: You will receive 1 supplemental assessment prorated from your date of event to the following June 30^th.
• January 1 to May 31: You will receive 2 supplemental assessments. The first will be prorated from your date of event to the following June 30^th. The second will be for the entire subsequent assessment year from July 1 to June 30^th.

Estimate Your Supplemental Taxes

This search tool is maintained by an independent data service. You can view property information and estimate supplemental taxes.

Supplemental Tax Estimator: After searching and selecting a parcel number, click on the Supplemental Tax Estimator Tab to see an estimate of your supplemental tax.

To estimate your supplemental tax, click here. 

Related Information

• California State Board of Equalization - Supplemental Assessment
• California State Board of Equalization - Supplemental Assessment FAQ's

Questions

If you have any questions, please contact our office.