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Supplemental Property Taxes

Supplemental assessment provisions were first enacted in 1983. This legislation subjects new construction and most changes in ownership of real property occurring on or after July 1, 1983 to immediate reassessment.

Supplemental taxes result from assessments adjusting taxes when new taxable values are determined following change of ownership of locally assessed property or completion of new construction on locally-assessed real property. The additional tax is owed because the County Assessor is required to immediately adjust the assessed value to reflect the new value of the property. Adjusted for the number of months left in the fiscal year, the Supplemental Tax Bill represents the tax due on the difference between the old and the new values.

Supplemental Tax Bills are separate from the regular property tax bill. It is the owner's responsibility to ensure payment of Supplemental Taxes as they cannot be billed to a lending agency.

Assessment Review and Appeals

You have the right to appeal the Supplemental Assessment within 60 days of the date of the Notice of Supplemental Assessment was mailed and before the tax bill was issued.
You may contact the Assessor Department through their website, by phone at (714) 834-2727 or at

Orange County Assessor Department
P.O. Box 149
Santa Ana, CA 92702

Assessment Appeals forms and instructions may be obtained from your local library, on the Internet at, or in person at the

Office of the Clerk of the Board of Supervisors
Assessment Appeals Division
400 W. Civic Center Drive, 6th Floor
Santa Ana, CA 92701

Note: If you have filed an appeal, you are still responsible for the payment of taxes.

Penalties for Secured Supplemental

If your first installment amount is unpaid after the first installment due date, a 10% penalty is added to the first installment amount due. If your second installment amount is unpaid after the second installment due date, a 10% penalty plus a $23.00 cost fee is added to the second installment amount due. After June 30, a $15 redemption fee and penalty in the amount of 1.5% per month will be added to the unpaid taxes and penalties listed on the bill.

Penalties for Unsecured Supplemental

If the amount due is unpaid after the delinquent date, a 10% penalty is added to the amount due. After 5 p.m. of the last day of the next succeeding month after the 10% penalty is added, a lien is recorded and penalty in the amount of 1.5% per month will be added to the unpaid taxes listed on the bill. A fee of $14 will be charged for releasing the lien.

Pay by Mail

IMPORTANT: Mail your payment(s) at least 3 days prior to delinquent date.

Pursuant to Revenue & Taxation Code Sec. 2512, to avoid penalties, payments must be postmarked on or before last payment date as State Law requires it to be treated as if it had been received on the date shown by the post office cancellation mark stamped on the envelope. Only U.S. Postal Service postmarks will be accepted. Office machine cancellation marks will not be accepted. When remitting payment, checks must be paid in U.S. Currency and drawn on a U.S. Bank. Our office will not pay for collection fees, conversion fees or any miscellaneous charges incurred for processing payment. If the Bank imposes a fee, the tax payment will be cancelled and delinquent fees and penalties will apply. Payments should be made payable to “County of Orange” and mailed to:


P.O. BOX 1438
SANTA ANA, CA 92702-1438

Pay by Credit Card

You may pay your tax bill by credit card for amounts up to $99,999 using your touch-tone telephone and dialing (714) 834-3411 or via the Internet. Acceptable credit cards over the phone and Internet are: Visa, MasterCard, Discover and American Express. Please note that a 2.29% service fee (with a minimum charge of $1.95) will be charged for this service.

Pay by ACH

Effective January 1, 1995, all taxpayers whose tax payments equal or exceed $25,000 per installment, are required to pay by ACH Credit. If your payment is less than $25,000, you may voluntarily make direct electronic payments of your taxes using ACH (Automated Clearinghouse) Debit.
When you use ACH Debit, you authorize the county to take the funds for your tax payment directly from your bank account on the day you initiate the transaction. When you use ACH Credit, you tell your bank how much and when to send money to the county to pay your taxes.

To sign up for ACH Credit contact your banking institution.

To pay by ACH Debit, please click here to pay by ACH Debit.

Pay in Person

The Office of Treasurer-Tax Collector is located at 601 North Ross Street, in Santa Ana, CA. We also have an easily accessible property tax payment drop box for your convenience located on the Ross Street side of the County Administration South Building located at 601 N. Ross St. Please do not deposit cash in the drop box.

Get a list of important tax dates.
Click on this link to estimate your supplemental taxes