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Alameda County, CA,

General & Ownership Information
(510) 272-3787

Business Personal Property:
(510) 272-3836

Our business hours are from 8:30AM to 5:00PM Monday through Friday except for holidays


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Decline in Market Value

The Assessor's Office is required to lower the assessment of real property to the lesser of its current market value or the factored Proposition 13 base year value as of January 1 of each year. That value is surrendered to the Auditor by July 1 and becomes the basis of the annual property tax billed by the Tax Collector.

The Assessor makes every effort to consider declines in value and to assess all property at the lesser of market value or factored base year value each year without the need for individual owners making an informal request or filing a formal appeal. Informal requests for review are considered individually by certified appraisers and can be filed by the property owner for the current year or the upcoming year. For more information, call (510) 272-3787.

More information on Decline in Value assessments

How does this impact your property taxes? In 1978, California voters passed Proposition 8, a constitutional amendment that allows a temporary reduction in assessed value when a property suffers a decline in market value. For property tax purposes a decline in value occurs when the current market value of your property is less than the assessed value as of lien date, January 1 of each year.

To view your current assessed value click on the link and type in your parcel number or address

You may not need to request an informal review of your property's assessment. Alameda County has been and will continue to be proactive in reviewing assessed values to ascertain whether temporary reductions are warranted. The 2020-21 tax year review includes all properties that were granted a reduced assessment for 2019-20. Our review will also encompass properties where no reduction was made for 2019-20 but may need a decreased assessment for 2020-21. Sales of similar properties that sold near the lien date, January 1, 2020 will be analyzed and compared to the properties under review to determine market value.

After the review is completed in June, all taxpayers will be notified of their 2020 assessed value during the latter part of July. Once notified, if you agree with the value no action on your part will be necessary and the annual tax bill sent out in October will reflect that assessment. If you have questions please call this office at (510) 272-3787 or come in person. The Assessor's office is located at 1221 Oak St., Rm. 145, Oakland, CA 94612-4288. Knowledgeable staff is available to assist you with your concerns from 8:30 a.m. to 5:00 p.m., Monday through Friday.

If you believe your assessed value is greater than market value on January 1, 2020 and have information you’d like us to consider, you may file an Informal Request for Reassessment with our office and a certified appraiser will review the data.

Decline in Market Value 2020/21 Informal Request for Reassessment  (PDF - 267kb)*

Decline in Market Value Information Brochure  (PDF - 178kb)*

However if after contacting this office your value concerns are not resolved, you must file an Assessment Appeal Application with the Clerk, Assessments Appeals Board, P.O. Box 1499, Oakland, CA 94612-1499 to protect your formal appeal rights. For information on how to obtain and complete an application call (510) 272-6352 or visit the Clerk's website at The appeal application must be filed between July 2 and September 15, 2020.

  • Decline in Value Qualifying Examples
      Example 1
      • I purchased my home in the early 1990s
      • The assessed value on my property for 2017-18 is $454,082.
      • The market value of my property as of January 1, 2017 was $660,000
      • Your property in this example does not qualify for decline in value relief, as the assessed value is lower than the market value.

      Example 2
      • I purchased my home in May 2009 for $600,000.
      • The assessed value of my property for 2017-18 is $665,724 ($600,000 x 1.10954).
      • Similar model homes near in time to January 1, 2017 sold for $575,000.
      • Your property in this example qualifies for decline in value relief, as the sales of comparable properties indicate that the market value on January 1, 2017 is lower than the assessed value.

      Example 3
      • I purchased my home in September 2007 for $700,000.
      • As of January 1, 2016 comparable sales indicated a market value of $650,000.
      • I was provided a temporary reduction for the 2016-17 year because the market value was less than the assessed value.
      • As of January 1, 2017 comparable sales indicate a market value of $625,000. Since the property qualified for a temporary reduction for 2016-17, our office will automatically review the assessed value for 2017-18 and based on the indicated value the property qualifies for a further reduced assessment of $625,000.

* Portable Document Format (PDF) file requires the free Adobe Reader.

** To view Microsoft Office Word, Excel, or PowerPoint documents, you can download a free trial version of Office 365. Per Microsoft, you will be able to continue viewing files even after the trial has expired.

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