This page helps with property tax tasks in Alameda County, California, including looking up secured, supplemental, and unsecured tax bills, reviewing due dates, and finding official payment or support channels.
The Alameda County Office of the Treasurer-Tax Collector provides the main property tax lookup and payment services, with separate online searches for real property and business or personal property taxes.
Alameda County property tax lookup
Use Alameda County’s online property tax system to look up or pay current property tax bills. Real property taxes are searched separately from unsecured taxes for boats, business personal property, and possessory interest.
- Property address or parcel number for secured and supplemental property taxes
- Assessee account number for unsecured supplemental property taxes
Choose the search that matches the type of bill you need.
- Open the secured and supplemental property tax search for real property bills.
- Enter the property address or parcel number as requested by the search page.
- Open the unsecured supplemental property tax search for business or personal property bills.
- Enter the assessee account number when searching unsecured taxes.
The parcel number should be entered as it appears on the tax bill, with dashes and no leading zeroes.
Secured and unsecured tax bill differences
Secured property taxes are taxes where the tax lien is against real property. The county’s real property option is used to pay, look up, or download secured or supplemental bills.
Unsecured property taxes apply to property that is not secured by a lien against real property sufficient to secure payment. Alameda County identifies examples such as office furniture, machinery, equipment, boats, airplanes, business personal property, and possessory interests.
For unsecured taxes, the online search uses the assessee account number rather than a property address or parcel number.
Property tax due dates and penalties
Current year secured property taxes are payable in two installments. Alameda County lists the following due and delinquency rules.
| Tax item | Due date | Delinquency rule |
|---|---|---|
| First secured installment | November 1 | Delinquent at 5:00 p.m. December 10, with a 10% penalty after that time |
| Second secured installment | February 1 of the following year | Delinquent at 5:00 p.m. April 10, with a 10% penalty and $10 cost after that time |
| Unsecured roll taxes as of July 31 | August 31 | Delinquent at 5:00 p.m., or close of business, on August 31 if unpaid, with a 10% penalty |
If December 10, April 10, or the applicable unsecured deadline falls on a Saturday, Sunday, or legal holiday, the penalty does not attach if payment is made by the stated deadline on the next business day.
Payment options and mailed payments
Alameda County states that paying online is the best way to pay property taxes and avoid late fees. Other payment methods include in person, by mail, by phone, and wire transfer.
Checks should be made payable to Treasurer Tax Collector, Alameda County. Mailed tax payments go to the Alameda County Treasurer-Tax Collector at the address listed in the contact section below.
Postmark notice: Alameda County states that USPS postmark regulations changed as of December 24, 2025. The postmark date is the date the item is first processed by automated processing equipment, not the date it is picked up from the mailbox. The Treasurer-Tax Collector encourages online e-check payment, which is free of charge.
Monthly payment considerations
Alameda County’s computer systems cannot accept more than the two annual secured property tax installments. The Treasurer-Tax Collector lists other options for taxpayers who need to plan monthly.
- Ask your lender about setting up an impound account so taxes are included in the monthly mortgage payment.
- Set aside funds monthly in a bank account for the property tax installments.
- Consider Easy Smart Pay for monthly secured property tax payments through an outside vendor.
Easy Smart Pay does not apply to supplemental property tax. Alameda County states that the service is endorsed by the county but is not affiliated with Alameda County, and the listed fee is 1.99%, subject to change.
Duplicate bills, address changes, and assessment questions
If you did not receive a secured or unsecured tax bill, Alameda County says you can order a duplicate bill by calling the Treasurer-Tax Collector, visiting the office, or using the county’s online property tax service.
Mailing address changes are handled through the Assessor’s Office. Alameda County states that a change of address cannot occur over the phone.
If you disagree with the assessed value on a secured tax bill, contact the Assessor’s Office for an informal assessment review. If you disagree with the assessed value on an unsecured tax bill based on an assigned valuation, contact the Assessor’s Office using the unsecured assessment phone line listed in the contact section.
Penalty waiver and delinquent tax forms
Alameda County provides application forms for specific property tax issues, including military property tax relief, installment plans for prior year secured property tax delinquencies, and an online penalty waiver form for late property tax payments.
The online penalty waiver form is for late property tax payments only. It is not for fees caused by returned checks from financial institutions. Alameda County states that penalties are imposed automatically by California law and may be canceled only under limited conditions.
For a penalty waiver request, have the tax bill available because the form requires information from the bill. The form also allows documentation uploads to support the request.
Property tax portal availability
The Alameda County property tax portal may be temporarily unavailable during maintenance and nightly processing. The listed maintenance windows are generally Sunday mornings from 7:00 to 9:00 a.m. and weeknights from 1:00 to 2:00 a.m.
The portal also allows users to subscribe for email reminders when important tax dates are approaching.
Property tax contacts
Use these Alameda County contacts for property tax payment, bill, assessment, and appeal questions.
-
Alameda County Property Tax Collection, 1221 Oak Street, Room 131, Oakland, CA 94612
Phone: (510) 272-6800
Fax: (510) 272-6807
Call Center Hours: 8:30 a.m. – 4:30 p.m.
Office Hours: 8:30 a.m. – 4:30 p.m. -
Assessor’s Office, 1221 Oak Street, Room 245, Oakland, California 94612-4288
Secured assessment review: (510) 272-3787
Unsecured assessment review: (510) 272-3836 -
Alameda County Assessment Appeals Board, County Administration Building, Room 536, 1221 Oak Street, Oakland, California 94612-4241
Secured assessment appeals: (510) 272-6347
Unsecured assessment appeals: (510) 272-6352
Common questions
Where can I search Alameda County secured property taxes?
Use the county’s real property tax search to look up secured and supplemental bills by property address or parcel number.
Where can I search Alameda County unsecured property taxes?
Use the unsecured supplemental property tax search when the bill is tied to an assessee account number.
When are Alameda County secured property taxes due?
The first installment is due November 1 and becomes delinquent after 5:00 p.m. December 10. The second installment is due February 1 and becomes delinquent after 5:00 p.m. April 10.
What should I do if I did not receive my tax bill?
You can order a duplicate tax bill by calling the Treasurer-Tax Collector at (510) 272-6800, visiting the office, or using the county’s online property tax service.
Can Alameda County accept monthly secured property tax payments?
The county’s systems cannot accept more than the two annual secured installments. The Treasurer-Tax Collector suggests lender impound accounts, a personal bank savings plan, or Easy Smart Pay as possible monthly planning options.
Who handles assessed value disagreements?
The Assessor’s Office handles informal assessment reviews. If the issue is not resolved, the Alameda County Assessment Appeals Board handles assessment appeal applications within the applicable filing period.