Last updated 2026-07-09
TL;DR
Alameda County (acgov.org) sets property taxes under California's Prop 13 framework: a 1% base rate plus local bonds and assessments, applied to your assessed value. Bills come out in October and are due in two installments, November 1 and February 1. You can appeal your assessed value to the Assessment Appeals Board, but the filing window is typically July 2 through November 30 each year.
What is the Alameda County property tax rate?
There is no single flat rate. Every parcel in Alameda County carries a base tax rate of 1% of assessed value, fixed by California's Proposition 13 (Article XIII A of the California Constitution). On top of that 1%, each parcel picks up charges for voter-approved general obligation bonds, special districts, and direct assessments. [1]
For most residential properties, the combined rate lands somewhere between 1.15% and 1.35% of assessed value. It varies by location. A home in Oakland Unified School District carries different bond charges than one in the Alameda Unified or San Leandro Unified districts. For the exact rate on your parcel, the Alameda County Auditor-Controller keeps a tax rate lookup tool on acgov.org. You enter your parcel number and it returns the full breakdown. [2]
Prop 13 also caps annual assessment increases at 2% per year unless the property changes ownership or gets new construction. That means a neighbor who bought in 1995 could be paying tax on a value that's a fraction of what yours reflects if you bought recently. Nobody set out to make the system feel unfair. That's how it works.
How is my Alameda County assessed value calculated?
California uses an acquisition-value system, not a market-value system. When you buy a property, the purchase price becomes your "base year value." The county assessor then adjusts that base by up to 2% per year under Prop 13 for as long as you own the property. [1]
The one big exception is a market-value decline. Under California Revenue and Taxation Code Section 51, the assessor must enroll the lower of (a) your Prop 13 adjusted base year value or (b) the property's current market value as of January 1. [3] When markets drop, the assessor is supposed to catch this and reduce your assessment automatically through what's called a "Prop 8" temporary reduction. In practice, the assessor does review values county-wide when markets fall, but individual properties sometimes slip through.
New construction adds to your base year value only for the part that's newly built. Put on a 500-square-foot addition and the assessor appraises just that addition at today's market value, then adds it to your existing base. The rest of the property keeps its old base year value. [1]
Your assessment notice arrives each spring, usually in late July for most property types. That notice is your starting point for deciding whether to appeal. Compare the assessed value on it to what you think you could actually sell the property for on January 1 of the tax year. If the assessed value is higher, you probably have a case.
When are Alameda County property tax bills due?
Alameda County splits annual property taxes into two installments. Here's the full calendar every owner should have memorized:
| Event | Date |
|---|---|
| Fiscal year begins | July 1 |
| Annual tax bills mailed | October (typically mid-month) |
| 1st installment due | November 1 |
| 1st installment delinquent | December 11 (10% penalty added) |
| 2nd installment due | February 1 |
| 2nd installment delinquent | April 11 (10% penalty + $10 fee) |
| Unpaid taxes become a lien | June 30 |
| Tax defaulted (5-year redemption period begins) | July 1 following delinquency |
The December and April delinquency dates are the ones people miss most. If December 10 falls on a weekend or holiday, the deadline shifts to the next business day, but don't count on that. [4]
One nuance for new buyers. If your lender collects taxes through an impound account, still verify the payment posts on time. Servicing transfers and escrow errors happen. You're the one who pays the penalty.
The county treasurer-tax collector takes payment online, by mail, and in person at 1221 Oak Street in Oakland. Online payments through ACH (echeck) have no fee. Credit card payments carry a service charge that usually runs around 2.5%, which adds up fast on a large bill. [4]
What exemptions can reduce my Alameda County property tax?
Several exemptions can cut your assessed value or your tax bill outright. The ones worth knowing:
Homeowners' Exemption. Any owner-occupied home qualifies for a $7,000 reduction in assessed value, saving roughly $70 per year (1% of $7,000). Small, but free. You file once and it auto-renews. The deadline to file for the first year is February 15 after you move in. [5]
Disabled Veterans' Exemption. Veterans with a service-connected disability rated 100% by the VA, or who are blind or have lost the use of two or more limbs, qualify for an exemption on the first $196,262 of assessed value (2024 figure, adjusted annually for the California CPI). Their surviving unremarried spouses also qualify. [5]
Senior Citizen Property Tax Postponement. This is a state program, not a county exemption, but Alameda residents use it. Homeowners 62 or older with household income under $45,810 (2024 threshold) can defer payment of their property taxes to the state, which places a lien on the property until it's sold or transferred. The state charges 7% annual interest on deferred amounts. [6]
Prop 19 Parent-Child and Grandparent-Grandchild Transfers. Under Proposition 19 (effective February 16, 2021), children who inherit a parent's primary residence can keep the parent's low assessed base value, but only if the child also makes it their primary residence within one year. The exclusion is capped: the assessed value transferred cannot exceed the parent's base year value plus $1,000,000 (2024 figure; adjusts with the California House Price Index). [7] This replaced the old Prop 58 rules, which were far more generous. If you inherited before February 16, 2021, Prop 58 still governs your transfer.
Other exemptions cover churches, charitable nonprofits, and disabled persons. Filing deadlines vary by exemption type. Check the Alameda County Assessor's exemptions page directly rather than trusting secondhand summaries.
How do I appeal my Alameda County property tax assessment?
The appeal runs through the Assessment Appeals Board (AAB), which is independent of the assessor's office. Here's how it works in practice.
Step 1: Know your filing window. For most properties, the annual filing period is July 2 through November 30. That window applies to the regular assessment roll. If your assessment changed because of a calamity, new construction, or a change in ownership, different timelines apply, so confirm your specific deadline at the AAB office. [8]
Step 2: File your application. The Application for Changed Assessment (form BOE-305-AH, from the State Board of Equalization) goes to the Clerk of the Board, not the assessor. You can file in person at 1221 Oak Street, Oakland, or by mail. Online filing is also available through the county. The filing fee is $30 for most residential properties. [8]
Step 3: Get your evidence ready before you file. The burden of proof is on you, the taxpayer. You have to show the assessor's value exceeds the property's fair market value as of January 1 of the tax year. Strong evidence includes recent comparable sales (three to five sales of similar properties that closed close to January 1), a licensed appraisal, or documented physical condition problems the assessor missed.
Step 4: Informal review option. Before your formal hearing, you can ask for an informal review directly with the assessor's office. It costs nothing extra and sometimes gets you a reduced assessment without a hearing. It does not pause your appeal deadline, so file the application first.
Step 5: The hearing. AAB hearings are quasi-judicial proceedings. The board hears both sides. You present your evidence; the assessor's representative presents theirs. The board issues a written decision. Win, and the county issues a refund with interest (set at the rate in California Revenue and Taxation Code Section 5151). [3]
Want to handle this yourself without paying a contingency firm a slice of your savings? The TaxFightBack DIY appeal kit walks you through comp selection, the BOE-305-AH form, and how to structure your argument for an AAB hearing in plain language.
One realistic note: AAB hearing wait times in Alameda County have historically run 12 to 24 months after filing, especially for residential cases. Budget your expectations.
What evidence wins an Alameda County property tax appeal?
The state's standard is clear. California Revenue and Taxation Code Section 1611.5 states: "The applicant has the burden of proof that the value on the assessment roll is incorrect and what the correct value is." [3] You can't just say the assessor is wrong. You have to show what the right number is.
For most residential appeals, comparable sales carry the most weight. The AAB looks for sales of similar homes in your neighborhood that closed on or near January 1 of the tax year (the lien date). Ideal comps sit within half a mile, within 10% of your home's square footage, and sold within six months of January 1. Three strong comps beat ten weak ones.
You can pull comps yourself from public records through the Alameda County Assessor's parcel search, from Zillow's sold filter, or from Redfin. The county recorder also keeps a public sales database. [2] If your comps consistently show a market value below your assessed value, lay them out in a simple table: address, sale date, sale price, price per square foot, and any adjustments needed to compare fairly to your property.
A licensed appraisal beats comps you assembled yourself, but it costs $400 to $800 and isn't always necessary for straightforward residential cases. For high-value properties or cases where the assessed value sits far above market, the appraisal usually pays for itself.
Physical condition evidence matters too. Deferred maintenance, foundation issues, unpermitted work the assessor valued incorrectly, or flood or fire damage: document it with dated photos and repair estimates from licensed contractors. The assessor's field data card (available through the assessor's office via a public records request) shows what physical characteristics the assessor assumed for your property. If those assumptions are wrong, you have a factual error argument, which is often easier to win than a pure market-value fight.
For how similar processes play out in neighboring counties, the la county property tax and santa clara property tax guides cover comparable California appeal frameworks with their own timing quirks.
What happens after a successful Alameda County property tax appeal?
If the AAB rules in your favor, the outcome hinges on whether the board adjusts your base year value or grants a temporary Prop 8 reduction.
A base year value reduction is permanent (until the property changes ownership or new construction occurs). It lowers every future year's bill because future Prop 13 increases compound from the lower base. This applies when you're challenging the value set at the time of purchase or a change in ownership.
A Prop 8 temporary reduction applies only to a specific tax year when market values dipped below your Prop 13 base. The assessor reviews it annually and can restore the value as the market recovers. You may find yourself back near your old assessment within a few years if prices rebound.
Either way, you get a refund (or credit) for overpaid taxes going back to the start of the tax year you appealed, plus interest. The interest rate on refunds under California Revenue and Taxation Code Section 5151 is set at the county pool rate or 3% per year, whichever is less. [3] That's not exciting interest, but it's something.
The refund check comes from the Alameda County Auditor-Controller, usually within 60 to 90 days of the board's decision becoming final. If you had an impound account, the refund may go to your lender first, who should then credit your escrow account.
How do I pay my Alameda County property tax bill?
The Alameda County Treasurer-Tax Collector handles all payments. You have several options:
Online: The county's secure payment portal at acgov.org takes e-checks (free) and credit or debit cards (fee of roughly 2.34% as of recent years, charged by the payment processor). Enter your parcel number or assessment number to pull up your bill. [4]
By mail: Make checks payable to "Treasurer-Tax Collector, County of Alameda" and mail to P.O. Box 1888, Oakland, CA 94604-1888. Your postmark must be on or before the delinquency date.
In person: 1221 Oak Street, Room 131, Oakland, CA 94612. Hours are typically Monday through Friday, 8:30 a.m. to 5:00 p.m. Cash, check, and money orders accepted.
Drop box: A 24-hour drop box sits outside 1221 Oak Street.
For background on how online payment options work across counties, see our piece on online tax payment for property.
One thing most people don't know: you can pay future installments early. The tax collector will accept your February installment in November if you want to simplify your finances or lock in a payment before year-end. This used to help with federal income tax deduction timing before the SALT cap changed the math for many people.
If you can't pay and delinquency is coming, contact the tax collector's office early. There's no formal payment plan statute for current-year taxes, but the office sometimes works with taxpayers in genuine hardship to avoid the full penalty cascade.
What is Prop 19 and how does it affect Alameda County property tax transfers?
Proposition 19 is the biggest structural change to California property tax transfers since Prop 13 itself. It passed in November 2020 and took effect February 16, 2021. [7]
For Alameda County homeowners 55 or older, severely disabled, or who lost a home to wildfire or disaster, Prop 19 expanded the ability to transfer your existing assessed base value to a replacement home anywhere in California, up to three times in your lifetime (before, most transfers were limited to the same county or a handful of participating counties). The replacement home's value can exceed your original home's value, and the base carries over with an adjustment for the difference. [7]
For inherited property, Prop 19 sharply narrowed the parent-child exclusion compared to old Prop 58. Under current rules, children must use an inherited home as their primary residence within one year to preserve the parent's base year value, and even then the exclusion has a $1,000,000 cap above the parent's assessed value. Rental properties, vacation homes, and commercial properties inherited from parents are now reassessed at market value at the time of transfer. This caught a lot of Alameda County families off guard and has driven dramatically higher tax bills on inherited investment properties.
If you inherited Alameda County property after February 16, 2021, and didn't file a claim for the exclusion within three years of the transfer date, you likely lost the chance for good. The Alameda County Assessor's office handles exclusion claims; the form is BOE-19-B (parent-to-child) or BOE-19-G (grandparent-to-grandchild). [7]
How does the Alameda County Assessor's office work and who should I contact?
Three separate offices handle property tax in Alameda County, and calling the wrong one wastes your afternoon.
Assessor's Office (assesses the value of your property): 1221 Oak Street, Suite 145, Oakland. Phone: (510) 272-3787. Website: acgov.org/assessor. Go here to correct errors in your property's physical description, apply for exemptions, or request your property record card. [9]
Treasurer-Tax Collector (sends bills and collects payments): 1221 Oak Street, Room 131, Oakland. Phone: (510) 272-6800. Website: acgov.org/treasurer. For payment questions, refunds, and delinquency concerns.
Clerk of the Assessment Appeals Board (manages appeal hearings): 1221 Oak Street, Room 536, Oakland. Phone: (510) 272-6352. Website: acgov.org/gsa/boards. For filing applications, hearing schedules, and appeal status. [8]
All three offices sit in the same building, which is handy. The assessor's office has an online parcel viewer where you can look up your parcel's assessed value, current ownership, and assessment history without making a call. That's usually your first stop before doing anything else.
What are common mistakes Alameda County homeowners make with property taxes?
Missing the appeal deadline is the most expensive mistake. November 30 is hard. There's no grace period and the AAB has no discretion to accept a late application for a regular roll appeal. [8] Mark it the day your assessment notice arrives.
Not checking your property record card is the second most common miss. The assessor's data on your home's square footage, bedroom count, bathroom count, and lot size may be wrong. If the assessor thinks you have a finished basement you don't, or 2,400 square feet when you have 2,000, you're paying tax on space that doesn't exist. Request your property record card, compare it to reality, and report any errors to the assessor right away. This kind of factual correction doesn't require a formal appeal in most cases.
Confusing assessed value with market value trips people up constantly. Your assessed value under Prop 13 isn't what the county thinks your home would sell for today. It's a historical number adjusted annually. If you're comparing your assessed value to your neighbor's Zillow estimate to decide whether to appeal, you're looking at the wrong number. The right question is whether your assessed value exceeds what your home would actually sell for on January 1 of the current tax year.
Forgetting supplemental tax bills catches new buyers off guard. When you buy, Alameda County issues a supplemental assessment reflecting the difference between the seller's old assessed value and your new purchase price. That generates a supplemental tax bill, separate from the regular annual bill. It can arrive months after closing, and it isn't collected through your impound account the same way. Many new owners simply don't expect it. [9]
For a broader grounding in how property tax systems work before digging into Alameda County specifics, the property tax taxation overview is a solid starting point.
How does Alameda County compare to other large California counties on property tax rates?
The 1% Prop 13 base rate is identical across every California county. The differences come from local bonds and assessments voted in by residents. Alameda County tends to carry higher total effective rates than some neighbors because its cities and school districts have passed a lot of bond measures over the years.
Here's a rough comparison of typical total effective rates for single-family homes (these are averages across all parcels in each county; your individual parcel will differ based on your district's bonds):
| County | Approximate average effective rate | Notes |
|---|---|---|
| Alameda | 1.20% to 1.35% | Multiple school and city bonds |
| Contra Costa | 1.15% to 1.30% | Similar bond structure |
| Santa Clara | 1.10% to 1.25% | Varies significantly by city |
| San Francisco | 1.15% to 1.20% | Fewer district-level bonds |
| Los Angeles | 1.15% to 1.30% | Wide variation by city and district |
These figures come from the California Board of Equalization's county-level data and individual county auditor reports. [10] The honest caveat: nobody publishes a single clean average effective rate that accounts for all direct assessments. The numbers above represent the range you see across typical residential parcels, not a precise statewide calculation.
One number that is precise: Alameda County collected roughly $2.7 billion in property tax revenue in fiscal year 2022-23, putting it among the top-five property tax revenue counties in California. [11]
Frequently asked questions
What is the Alameda County property tax rate for 2024?
There is no single rate. Every parcel in Alameda County carries California's fixed 1% base rate under Prop 13, plus local voter-approved bonds and direct assessments that vary by location. For most residential properties, the combined rate falls between 1.15% and 1.35%. To find your exact rate, use the parcel tax rate lookup on acgov.org and enter your assessor parcel number.
When are Alameda County property taxes due in 2024-2025?
The first installment is due November 1 and becomes delinquent on December 10 (a 10% penalty applies after that date). The second installment is due February 1 and becomes delinquent on April 10 (10% penalty plus a $10 cost fee). If either date falls on a weekend or holiday, the deadline shifts to the next business day. Bills are mailed in October.
How do I appeal my Alameda County property tax assessment?
File form BOE-305-AH with the Clerk of the Assessment Appeals Board by November 30. The filing fee is $30 for most residential properties. You then gather evidence showing your property's fair market value as of January 1 was below the assessed value on your notice. Evidence typically includes comparable sales and, for larger properties, a licensed appraisal. The board schedules a hearing and issues a written decision.
What is the deadline to file an Alameda County property tax appeal?
For the regular assessment roll, the filing window is July 2 through November 30 each year. That window is hard: there is no grace period. Different deadlines apply for supplemental assessments (after a purchase or new construction), so confirm your specific deadline with the AAB Clerk's office at (510) 272-6352 based on the assessment notice you received.
How do I apply for the Alameda County homeowners' exemption?
Owner-occupants file a one-time application with the Alameda County Assessor's office. The exemption reduces assessed value by $7,000, saving roughly $70 per year. The first-year filing deadline is February 15 following the year you moved in. Once granted, it renews automatically as long as you continue to occupy the property as your primary residence. The form is available at acgov.org/assessor.
What does Prop 13 mean for my Alameda County property tax?
Under Proposition 13, the assessed value of your property is set at the purchase price (the "base year value") and can increase by no more than 2% per year as long as you own it. When the property sells or major new construction occurs, it is reassessed at current market value. This means long-time owners often pay taxes on values far below current market prices, while recent buyers pay on full purchase price.
Does Alameda County have a senior property tax exemption or freeze?
Alameda County itself does not freeze assessed values for seniors. However, California's state Senior Citizen Property Tax Postponement program allows homeowners 62 or older with household income under $45,810 (2024) to defer property tax payments to the state. The state charges 7% annual interest and places a lien on the property. Applications go through the California State Controller's Office, not the county.
How do I find my Alameda County parcel number?
Your assessor parcel number (APN) appears on your property tax bill and on your deed. If you do not have either handy, search for your property by address on the Alameda County Assessor's online parcel viewer at acgov.org/assessor. The parcel viewer also shows your current assessed value, ownership history, and basic property characteristics without any login.
What happens if I miss the Alameda County property tax deadline?
A 10% penalty is added to the unpaid installment the day after the delinquency date (December 10 for the first installment, April 10 for the second). The second installment also gets a $10 fee. If taxes remain unpaid through June 30, the property becomes tax-defaulted and a 1.5% per month penalty begins accruing. After five years of default, the county can initiate a tax sale.
How do supplemental property tax bills work in Alameda County?
When a property changes ownership or undergoes new construction, the Alameda County Assessor issues a supplemental assessment reflecting the change in value from the prior assessment to the new one. This generates a separate supplemental tax bill, prorated for the remaining portion of the fiscal year. New buyers often receive this bill months after closing; it is not typically included in your regular impound account.
Can I get a property tax reduction if my home's value dropped?
Yes. Under California Revenue and Taxation Code Section 51, the assessor must enroll the lower of your Prop 13 adjusted base year value or current market value as of January 1. If your market value dropped below your base, you can request a temporary Prop 8 reduction by contacting the assessor's office or filing an appeal with the AAB by November 30. The reduction lasts only until market values recover.
How does Prop 19 affect inheriting Alameda County property?
Under Prop 19 (effective February 16, 2021), children who inherit a parent's primary residence can keep the parent's low assessed base value only if they also use the home as their primary residence within one year. The exclusion is capped at $1,000,000 above the parent's base assessed value. Inherited rental or commercial properties are now reassessed at market value at transfer. The old Prop 58 unlimited exclusion no longer applies.
What is the Alameda County Assessment Appeals Board and how independent is it?
The Assessment Appeals Board is a quasi-judicial body appointed by the Alameda County Board of Supervisors, separate from the Assessor's office. It hears disputes between taxpayers and the assessor about assessed values. The board follows California state law and Board of Equalization guidelines. It can accept, reduce, or (rarely) increase an assessed value. Its decisions are binding on the assessor for the tax year appealed.
Sources
- Alameda County Assessor's Office, Property Search and Parcel Viewer: The Alameda County Assessor provides an online parcel viewer with assessed value, ownership history, and property characteristics by parcel number.
- California Revenue and Taxation Code, Division 1, Part 0.5 (Sections 51, 1611.5, 5151): R&TC Section 51 requires enrollment of the lower of base year value or market value; Section 1611.5 places the burden of proof on the taxpayer; Section 5151 sets the interest rate on refunds.
- Alameda County Assessor's Office, Exemptions: Homeowners' exemption reduces assessed value by $7,000; Disabled Veterans' exemption applies to assessed value up to $196,262 for qualifying veterans.
- California State Controller's Office, Senior Citizen Property Tax Postponement Program: Homeowners 62 or older with household income under $45,810 (2024) can defer property taxes at 7% annual interest; the state places a lien on the property.
- Alameda County Assessment Appeals Board, How to Appeal Your Property Assessment: The regular appeal filing window is July 2 through November 30; the $30 filing fee applies to most residential applications; the BOE-305-AH form is filed with the Clerk of the Board.
- Alameda County Assessor's Office, Supplemental Assessments: When a property changes ownership or undergoes new construction, the assessor issues a supplemental assessment prorated to the remaining fiscal year, generating a separate supplemental tax bill.
- California State Board of Equalization, Annual Report: Property Tax Data: County-level data shows average effective rates for California counties; Alameda County's combined rate for residential properties typically falls between 1.20% and 1.35% when bond and assessment charges are included.
- Alameda County Auditor-Controller Agency, Annual Comprehensive Financial Report FY 2022-23: Alameda County collected approximately $2.7 billion in property tax revenue in fiscal year 2022-23.