Resources for Property Owners

The Alameda County Assessor’s Office provides information and resources to help property owners understand their assessments, exemptions, and rights. Below you will find helpful links organized by topic.

General Information for Property Owners

• The Property Tax System – Learn how property taxes are calculated in Alameda County.
• Proposition 13 – Understand how Prop 13 limits the tax rate and assessed value increases.
• Proposition 19 – Information about the transfer of base year values for eligible homeowners.
• Change in Ownership Reappraisal – What triggers a reassessment when property changes hands.
• New Construction Reappraisal – How new construction or improvements affect your assessed value.
• Supplemental Assessment – Learn about supplemental tax bills resulting from changes in ownership or new construction.
• Supplemental Tax Estimator – Estimate your supplemental taxes online.
• Property Ownership Information – Access property ownership records and details.
• Manufactured Homes – Assessment information specific to manufactured and mobile homes.
• Possessory Interests – Information about possessory interest assessments on government-owned property.

Lower Your Assessment

• Decline in Market Value – Request a review if you believe your property’s market value has declined below its assessed value.
• Why Assessed Value May Increase More than 2% – Understand the circumstances under which your assessed value may rise beyond the standard 2% annual increase.
• Exemptions – Learn about the Homeowners’ Exemption, Disabled Veterans’ Exemption, and other available exemptions.
• Exclusions from Reassessment – Find out if you qualify for exclusions from reassessment, including parent-child and grandparent-grandchild transfers.
• Assessment Appeals – Learn how to file a formal appeal if you disagree with your property’s assessed value.

Tax Bill Information

• Pay My Tax Bill – Visit the Alameda County Treasurer-Tax Collector’s Office to view and pay your property tax bill online.
• Supplemental Tax Bills – Understand supplemental tax bills and when they are issued.
• Supplemental Tax Estimator – Calculate your estimated supplemental tax amount.

Forms, Records & Maps

• Assessor Forms – Download forms for exemptions, exclusions, address changes, and more.
• Assessor’s Records – Access public assessment records.
• Assessor’s Maps – View and download parcel maps.
• Parcel Viewer – Look up a parcel using the interactive map.
• Data for Sale Fee Schedule – Request assessment data and view associated fees.

Important Dates & Resources

• Calendar & Important Dates – View key dates in the annual assessment cycle.
• Glossary – Definitions of common property tax and assessment terms.
• Change Mailing Address – Update the mailing address on file for your property.

Death-Related Property Information

• Navigating Loss: Death of a Property Owner – Information about reassessment, exclusions, and required filings when a property owner passes away.

Business & Special Property

• Business Personal Property – Filing requirements for businesses operating in Alameda County.
• Escape Assessments – Learn about assessments issued for prior-year corrections.

No Charge to File

There is no charge to file for a Homeowners’ Exemption, request an informal review of your assessed value, or file an Assessment Appeal. Beware of any company that charges a fee for these free services.

Contact Us

If you have questions, please visit our Visit or Contact Us page or call (510) 272-3787.