How to Appeal Property Taxes in California (2025 Guide)

Navigating the property tax appeal process can seem daunting. Many homeowners feel overwhelmed by the complexity of tax assessments, interacting with their local county government, and compiling the right information to win an appeal. However, as a homeowner, this is your right, and your local county has set up infrastructure to allow homeowners to ensure their properties are being fairly assessed and taxed.

Property taxes are based on assessed property values. However, these assessments may not always reflect the actual market value of a property. This discrepancy can lead to higher tax bills than necessary.

Appealing your property tax assessment is a legal right. It offers a chance to correct any errors and potentially lower your tax burden. The process involves gathering evidence and presenting a strong case to the county assessor.

Knowing the steps and deadlines is essential. With the right approach, you can successfully challenge your property tax assessment. This guide will help you navigate the process with confidence.

How California Property Tax Assessments Work Under Proposition 13

To arrive at your annual tax assessment, the county assessor assigns a “base-year value”—usually the price you paid when you bought the home. From that starting point, Proposition 13 allows the assessed value to rise only by 2% each year. The cap applies even if market prices skyrocket, which is why longtime owners often pay far less than recent buyers in similar homes.

Two common events can override the cap: (1) a change in ownership and (2) new construction or major additions. Either triggers a full reassessment of just the affected portion, setting a new base-year value that future 2 percent increases build on.

In practice, what this means is your property is typically assessed at the purchase price of the house, plus 2% for every year you have owned the property.

When Should You File a Property Tax Appeal?

To understand whether you should appeal your property tax bill, it is important to differentiate two key terms:

• Market value: The estimated price of your property if you were to sell it in an arms-length transaction.
• Assessed value: The value the assessor ascribes to your property, described above.

If the market value of the home is less than the assessed value, that means you are being overtaxed by the county. In those cases, you should appeal your property tax assessment to lower your property taxes.

Tip: Parcel can help you determine your market value and assessed value with a free evaluation of your property.

Challenging a property tax assessment can lead to significant savings. If the assessment is inaccurate, you might be paying more than necessary. Determining the validity of your assessment is crucial to avoid overpayment.

While a decline in market value is one of the primary reasons to appeal your taxes, there are a number of other reasons:

• Mistakes in property data used by the assessor.
• Discrepancies in comparisons with similar properties.
• The county inaccurately changed your base-year value, e.g. if you moved your property into a trust, this can inadvertently trigger a re-assessment

Step-by-Step Guide: Filing a California Property Tax Appeal

Appealing property taxes can seem daunting, but breaking it down into steps can simplify the process:

1. Submit an Application: First, you will need to submit an appeal application to your county. Those can be found on your local county's website. For instance, the San Francisco County appeal application can be found here. Information that needs to be included in the form includes the property you are appealing, your contact information, and what you believe the correct market value for the home is. Note that you must submit the application during the appeal window. Every county varies, but typically the appeal window opens on July 2nd, and ends between mid-September and the end of November.
2. Provide Evidence: Once the county receives your application, they will request supplementary evidence to support your appeal. This includes gathering recent sales data from similar homes, recent appraisals, or photographs showing property conditions. Compelling evidence strengthens your case and increases your chances of success.
3. Appeal Hearing: From there, the county will schedule a hearing. These can take place in-person or online, depending on the county. This hearing is an opportunity to present your evidence and argue your case to lower your assessment.
4. Decision: Following this hearing, an independent assessment appeals board will make a determination on the correct assessment value for your property for the year. The hearing can result in: 1) a decrease in assessment, 2) no change in assessment, or 3) an increase in assessment - so make sure the evidence you bring is compelling!

Gathering Evidence for a Successful Appeal

Gathering strong, relevant evidence is necessary to win your appeal. Start with recent home sale prices in your neighborhood. Look for homes similar in size and type. Make sure the comparables are also within a relevant time window. The assessor does not allow comparables past April 1 of the year you are contesting the property, and prefers them to be as close to January 1 (of the current tax year) as possible.

Here's a list of valuable evidence:

• Recent sales data for comparable properties
• Professional appraisal reports
• Photographs of property condition

Each piece of evidence builds a stronger case for your appeal. Typically, the assessor likes to see 3-5 comparables sales to justify your market value.

2025 Appeal Deadlines & Filing Requirements

Understanding deadlines is vital in the property tax appeal process. Missing a deadline can forfeit your right to appeal. Each county has its own timeline, so check local regulations. Some major county deadlines include:

• Alameda County: July 2 to September 15
• Los Angeles County: July 2 to November 30
• Santa Clara County: July 2 to September 15
• San Francisco County: July 2 to September 15
• San Mateo County: July 2 to November 30

Be aware of these common deadlines and requirements:

• Filing date for initial appeal
• Submission of supporting documents - the assessor typically gives you 30 days to respond to requests for evidence, which need to be mailed in
• Date for your hearing - the assessor will give you 60 days notice of the time / date of the hearing, but once it is set, you cannot move it

Make sure to submit all required documents accurately. Any issues with paperwork or timelines can delay or cancel your appeal.

Tips to Win Your Property Tax Appeal

According to the California State Board of Equalization, 38% of the assessment-appeal cases that county boards decided in fiscal-year 2023-24 resulted in a lower assessed value for the owner—meaning nearly four out of ten appellants walked away with a tax savings.

To put yourself in the strongest position, assemble evidence the assessor can verify quickly:

• Pull at least three recent, arms-length sales of truly comparable homes—similar square footage, bedroom count, lot size, and neighborhood—closed as close as possible to the January 1 lien date
• Print the full MLS sheets and highlight how each sale differs from your property, then adjust values (e.g., subtract for your home’s original kitchen or add for your extra bath) so the assessor sees an apples-to-apples comparison
• Bring photos that document any deferred maintenance—roof wear, foundation cracks, outdated HVAC—to justify a lower valuation, and include repair bids to attach dollar figures to those defects
• Double-check the assessor’s parcel record for clerical errors such as an overstated living area or an unpermitted addition
• File the appeal on time, keep copies of every form you submit, and during the hearing stick to facts and numbers, addressing objections calmly with the documentation in front of you.

Need Help Appealing Your Property Taxes?

If paperwork, deadlines, and valuation formulas feel like a full-time job, it may be worth bringing in specialists.

Parcel’s expert property-tax agents can manage the entire appeal for you—from gathering sales comps and completing county forms to negotiating with the assessor’s office and presenting your case at the hearing.

Our team has handled thousands of successful appeals across California and works on a contingency basis, so you pay nothing unless we lower your bill. To see how much you could save, schedule a free tax assessment or schedule a complementary 15-minute consultation.

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