Oct 24, 2026 · By Oanh Nguyen · Broker & Loan Officer · Buying
Property tax is one of the biggest parts of owning a home. It also surprises a lot of buyers, especially first-time buyers.
I see the same questions over and over. How much will my taxes be? What is Prop 13? What is Mello-Roos? Why did I get a second tax bill after I bought?
In this post, I will walk you through the basics in plain English, using official sources. I will also show you how I check the taxes on a specific home.
One important note before I start. I am a real estate broker and loan officer, not a tax advisor. For your own situation, talk to a CPA, a tax attorney or the county assessor. This post is general information to help you ask the right questions.
Prop 13 in Plain English
California's Proposition 13 sets the ground rules for property taxes. According to the State Board of Equalization (Publication 29, March 2025):
- The general property tax is limited to 1% of a property's taxable value.
- Taxable value can generally rise no more than 2% a year.
- A property is reassessed to current market value when it changes ownership or when new construction is completed.
So when you buy, your home is generally reassessed based on its value at the time of your purchase. The seller's lower taxable value does not carry over to you.
That is why two similar homes on the same street can have very different tax bills. One owner may have bought many years ago. The other may have bought last year.
The 1% Is Not the Whole Bill
Many people hear "1%" and stop there. But your tax bill can include more than the 1% general levy.
Voter-approved debt. Local bonds approved by voters add to the rate. Alameda County's Auditor-Controller explains that these can push the total rate above 1%. These bonds often pay for things like schools or public projects.
Special assessments and fixed charges. Local districts can add these to your bill. They are not based on your home's value. They may cover services like sewer, lighting or other local programs. Alameda County says only the city or district that placed a charge can change it, and its contact is listed on the bill.
Special taxes, such as Mello-Roos. I cover these in their own section below.
What a Tax Rate Area Is
Every property sits in a "tax rate area." Each area has its own mix of voter-approved debt and local charges.
Two homes in the same city can have different total rates. Two homes in the same ZIP code can too. That is why I don't quote a single tax rate for a ZIP code or a city. I look at the actual bill for the actual home.
Alameda County notes that a property's tax rate area appears on that year's tax bill. You can find bills through the county's online property tax lookup.
Key Dates on the Tax Calendar
The State Board of Equalization lists these dates for the regular annual tax bill:
| Item | Date |
|---|---|
| Lien date | January 1 |
| First installment due | November 1 |
| First installment delinquent | December 10 |
| Second installment due | February 1 |
| Second installment delinquent | April 10 |
Source: California State Board of Equalization, Publication 29, March 2025.
If your lender collects taxes in an impound account, it usually pays these bills for you. Still, check that they were paid. If you pay your own taxes, put these dates on your calendar.
The Homeowners' Exemption
If the home will be your main residence, ask the county assessor about the homeowners' exemption.
According to the State Board of Equalization, the California Constitution requires a $7,000 reduction of taxable value for qualifying owner-occupied homes. The homeowner makes a simple one-time filing with the county assessor. Rentals and vacation homes do not qualify.
It is a small reduction, but it is easy to miss. Check with your county assessor on how and when to file.
Watch for the Supplemental Bill
After you buy, you may get a separate "supplemental" tax bill. It covers the difference between the old taxable value and your new one, for the rest of the tax year.
The Alameda County Assessor says:
- The increase starts the first day of the month after the transfer.
- The bill is prorated through June 30.
- There is no set deadline to send it, but most are mailed within 12 months.
- The owner is responsible for it, even if the lender pays the regular taxes from an impound account.
Plan for it. It catches many buyers off guard. Alameda County also offers an online supplemental tax estimator, linked below.
What Is Mello-Roos?
Mello-Roos is a special tax. It is set up under California's Mello-Roos Community Facilities Act. It usually helps pay for things like roads, schools or parks that serve a newer development.
A few things to know:
- It appears as a separate line on the tax bill.
- It can last for many years. The length depends on the district.
- The amount depends on the district's rules. It is not based on the 1% formula.
The seller's disclosures and the preliminary title report can show whether a property is subject to a Mello-Roos special tax. If you see one, contact the agency listed on the tax bill for details.
Not every newer home has Mello-Roos. Some older areas have other assessments. The only way to know is to check the specific property.
How I Check the Taxes on a Specific Home
Before my buyers remove contingencies, I help them review the taxes. Here is my process.
- Pull the current tax bill. I look at each line, not just the total.
- Separate the parts. The 1% general levy, voter-approved debt and any special taxes or charges.
- Read the preliminary title report. It can show special districts and assessments.
- Review the seller's disclosures. Including any Mello-Roos or special tax notice.
- Flag anything unclear. Then point you to the county or district listed on the bill.
How Taxes Fit Into Your Monthly Budget
When you compare homes, look at the full monthly cost, not just the price.
Property taxes, insurance, HOA dues and any special taxes all add up. Two homes with the same price can have very different monthly costs.
If you are getting a loan, your lender will include an estimate of property taxes when it reviews what you can afford. As a loan officer, I build these into the numbers from the start. I always encourage buyers to confirm tax details with the county or a CPA.
What Happens If You Remodel Later
Many of my clients plan to update a home after they buy. I hear questions about this often.
Remember the Board of Equalization's rule: a property can be reassessed when new construction is completed. That means some projects, like an addition, may raise your taxable value. Other work may not.
How a specific project is treated is up to the county assessor. Before a big remodel, ask the assessor's office how it may affect your taxes. A CPA can help you plan.
Common Property Tax Mistakes I See
These are the mistakes that cost buyers the most stress. All of them are avoidable.
Using the seller's tax bill as your budget. The seller's bill reflects the seller's taxable value. Yours will likely be different after the sale.
Forgetting the supplemental bill. It can arrive months after closing. Set money aside for it.
Assuming every home in a city has the same rate. Tax rate areas and special charges vary from one property to the next.
Skipping the line items. Special taxes and fixed charges can be a real part of the bill. Read every line.
Not filing for the homeowners' exemption. If you qualify, it is a simple one-time filing.
Missing a due date. If you pay your own taxes, mark the installment dates on your calendar.
A Hypothetical Example
This example is made up to show the process. It is not based on any real home.
A buyer compares two homes with similar prices. The first is an older home. Its bill shows the 1% levy, some voter-approved debt and a few small fixed charges.
The second is in a newer development. Its bill shows the same kinds of items, plus a separate special tax line.
The buyer asks the district listed on the second bill how long the special tax lasts and how it is calculated. With the answers, they compare the full monthly cost of both homes.
Frequently Asked Questions
What is the property tax rate in San Jose or the East Bay?
There isn't one rate. The general levy is limited to 1% of taxable value, but voter-approved debt and local charges are added, and these vary by tax rate area. Check the actual bill for the home.
Will my taxes be based on what I paid?
Generally, a home is reassessed when it changes ownership. Ask the county assessor how this applies to your purchase.
Can my taxes go up every year?
Under Prop 13, taxable value can generally rise no more than 2% a year. Voter-approved debt and local charges can also change.
What is a supplemental tax bill?
It is a separate bill for the difference between the old taxable value and the new one, for the rest of the tax year. The owner is responsible for it, even with an impound account.
How do I know if a home has Mello-Roos?
Look at the current tax bill, the preliminary title report and the seller's disclosures. Then confirm with the agency listed on the bill.
Can I lower my property taxes?
Ask the county assessor about the homeowners' exemption if the home is your main residence. If you think the value is wrong, the assessor's office can explain your options. A CPA or tax attorney can advise you.
How are taxes split with the seller at closing?
Property taxes are often prorated between buyer and seller in escrow, based on the purchase contract. Your escrow officer will show the details on your closing statement. Ask them to walk you through it.
Who do I call with tax questions?
For value and exemptions, the county assessor. For bills and payments, the county tax collector. For a special tax or charge, the agency listed on the bill. For advice, a CPA or tax attorney.
The Bottom Line
California property taxes start with Prop 13's 1% limit, but the full bill usually includes more. Voter-approved debt, local charges and special taxes like Mello-Roos can all add to it.
When you buy, plan for a reassessment and a supplemental bill. If the home is your main residence, ask about the homeowners' exemption.
Never estimate taxes from a rule of thumb. Look at the actual bill for the actual home. Then have a CPA, a tax attorney or the county confirm what applies to you. I will help you find the information and ask the right questions.
Official Places to Look
- Santa Clara County Assessor: https://asr.santaclaracounty.gov/home
- Alameda County Assessor, supplemental assessments: https://www.acassessor.org/homeowners/supplemental-assessment/
- Alameda County supplemental tax estimator: https://propinfo.acgov.org/SubTaxesCalculator/TaxCalculator.html
- Alameda County property tax FAQ: https://auditor.alamedacountyca.gov/tax-faqs/
Sources
- California State Board of Equalization, California Property Tax: An Overview, Publication 29, March 2025: https://www.boe.ca.gov/proptaxes/pdf/pub29.pdf
- Alameda County Auditor-Controller, Property Tax FAQs (accessed October 26, 2026): https://auditor.alamedacountyca.gov/tax-faqs/
- Alameda County Assessor, Supplemental Assessment (accessed October 26, 2026): https://www.acassessor.org/homeowners/supplemental-assessment/
Want help reading a tax bill on a home you like? Call or text me at 408-780-1188, or email onrealtygroup@gmail.com.
Oanh Nguyen · Broker & Loan Officer · On Realty Group, brokered by LPT Realty · BRE #02133991 · NMLS 2020335
Equal Housing Opportunity.
Disclaimer: This post is general information only, not legal, tax, financial or investment advice; consult a CPA, attorney or the county assessor about your situation.