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Frequently Asked Questions

This page is for General Questions and they are listed below. FAQs for specific sections are on their own page, and those links are provided below as well.

General Questions

General Questions:
  • Q: What do I do if I believe that my assessed value should be reduced or that my property taxes are too high? 

    A: This tax year, the Assessor’s Office reviewed the assessed value of all properties in the county for which a reduction in assessed value had been made due to the decline in market value for last year’s tax roll . By law the date of valuation, or lien date, for property tax purposes is January 1st. When estimating the fair market value of a property, comparable sales occurring more than 90 days after the lien date, that is, after March 31st, may not be considered. Therefore, current sales may not be used to estimate the assessed value of a property for the tax year. 

    If you have evidence that your assessed value is significantly greater than its market value on January1, of this year, you may file an appeal with the Clerk of the Board.  The deadline to file an appeal is November 30.

  • Q: My lender has notified me that my payment is being increased and/or they require an estimated tax bill to reduce my payment, will the Assessor’s office correct this or provide an estimated tax bill?

    A. The Tax Collector’s Office issues the regular secured property tax bills in October. Those bills are based on the value shown on the assessor’s records the preceding January first. If you bought your property after January first, an adjustment will be made on the supplemental roll. However, the regular bill will be due and payable as issued.

    If the assessed value is significantly greater than your purchase price, and you have an impound account, your impound account may not have enough money in it to cover the entire bill. In that case, lenders typically will pay the bill, then bill you for the shortage. Borrowers usually are given the option of sending in the total shortfall or of spreading out the amount over the next year in the form of an increased monthly payment.

    When we process your deed, we will send you a Notice of Supplemental Assessment that will show you the value on this year’s regular roll, as well as your new base year value. The difference between those two amounts is the supplemental assessment shown on the Notice.

    If the supplemental assessment is a negative amount, you will receive a supplemental refund. Refunds are issued by the Auditor/Controller’s Office. The time from the date of your Notice of Supplemental Assessment and the refund date is usually at least 90 days.

    If you are due a supplemental refund, after receiving your Notice of Supplemental Assessment you may want to contact your lender to see if you should send them a copy of the Notice. You might want to discuss with your lender the possibility of sending them the supplemental refund in order to reduce your monthly liability.

    A revised regular bill will not be issued. The Assessor’s Office is unable to provide estimated bills and any negotiations regarding impound payments are between you and your lender. Calculation of property tax bills is the responsibility of the San Joaquin County Auditor Controller’s Office. You may contact them for an estimated tax bill at 468-3925.

  • Q. What is a Notice of Supplemental Assessment?

    A. Under the provisions of Proposition 13, property must be reassessed at market value whenever there is a change in ownership or new construction is completed. A new Base Year Value is established and a supplemental assessment is created.

    The new base year value must be the Fair Market Value of the property on the date of the change. If a property has sold, and the purchase price is the same as the market value, then the reported purchase price is enrolled as the new base year value. But if the purchase price is significantly higher or lower than the Market Value of the property on the change date, the assessor is required by law to enroll the Market Value. Market Value is determined by doing an appraisal.

    A supplemental assessment is the difference between the new base year value and the value on the assessor’s records for the affected tax year or years. Changes that occur between January and May will create two supplemental assessments; changes occurring between June and December will create one supplemental assessment. The regular tax bill will not be changed or re-issued.

    Supplemental assessments are effective the first day of the month following the month in which the change occurs. Supplemental assessments that happen because of an increase in assessed value result in supplemental property tax bills. Supplemental assessments that happen because of a decrease in assessed value result in supplemental refunds being issued. The amount of the supplemental bill or refund is calculated by multiplying the tax rate times the supplemental assessment. Both supplemental bills and supplemental refunds are then pro-rated to cover only the time during the tax year that someone owns a property. Multiple activities during a tax year will result in multiple supplemental assessments; each bill or refund will be pro-rated to cover an assessee’s period of ownership.

    The supplemental roll is completely separate from the regular roll. The regular roll is prepared once a year. It is effective January 1st and is delivered to the Auditor’s Office each year on July 1st. The supplemental roll is created throughout the year as changes are processed, and it is delivered periodically through the year.

    Supplemental bills or refunds are always mailed directly to the property owner.

  • Q: Are there special programs available for Senior Citizens?

    A: The State Controller's Property Tax Postponement Program allows qualified homeowners who are seniors (at least 62 years of age), are blind, or have a disability to defer payment of property taxes on their principal residence. For more information, you can contact the State Controller’s Office at 1-800-952-5661 or go to their website


  • Q: If I give property to my children, will it be reassessed?

    A: Legislation was passed in 1986 excluding from reassessment transfers between parents and children of the principal residence and 1 million assessed value of other property. A claim form must be timely filed with the Assessor’s Office to qualify. For additional information regarding this exclusion, contact our office at 209-468-2658.

    This form is available online. Click here for the form.

  • Q: I am over 55 and wish to move to a smaller home. Will my taxes go up?  

    A: Legislation was passed in 1986 allowing those 55 and over to transfer the assessed value of their principal residence to a replacement residence in the same county if the value of the new residence is equal to or less than that of the original residence when sold. A claim form must be timely filed with the Assessor’s Office to qualify. San Joaquin County does not accept transfers from other counties. For additional information regarding this exclusion, contact our office at 209-468-2658.

    This form is available online. Click here for the form.  

  • Q: If I have an addition to my home, will you reappraise the entire property?

    A: No. Only the value of your new addition will be added to your current assessed value.

  • Q: If I do the work myself, will I only be assessed on the cost of the materials?

    A: No. New construction is assessed at the market value added to the property.

  • Q: If I add my spouse on the deed to my property , will it be reappraised?

    A: No. Transfers between spouses do not constitute a reappraisal event.

  • Q: Is property assessed at the price paid?

    A: Not always. Real property is valued at its current market value at the time it changes ownership. In a majority of cases, the sales price equals market value, but not always.