How to Appeal Your Property Tax Assessment in LA County (Step-by-Step)
The complete homeowner's guide to challenging your LA County property tax assessment, from finding your assessed value to winning your hearing at the Assessment Appeals Board.
Every January 1, the LA County Assessor establishes the taxable value of your property. If that number is higher than what your home would actually sell for, you are overpaying your property taxes. In a county with 2.6 million parcels and an Assessor's office that processes assessments en masse, errors and overvaluations happen more often than most Pasadena and SGV homeowners realize.
I have helped clients across the San Gabriel Valley and Greater Pasadena area identify when their assessments were inflated, and more importantly, what to do about it. Whether you recently purchased a home in Arcadia and received a supplemental bill that seems too high, or you own a property in Alhambra that has declined in value since your base year, this guide walks you through every step of the appeal process.
The good news: filing a property tax appeal in LA County is free, the process is straightforward if you prepare properly, and your taxes cannot increase as a result of filing. The only risk is your time.
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- How LA County Property Taxes Actually Work (Prop 13)
- When You Should Appeal Your Assessment
- Critical Deadlines: The Filing Window
- Informal Review vs. Formal Appeal (Comparison)
- Step-by-Step: Filing Your Property Tax Appeal
- How to Gather Comparable Sales Evidence
- Prop 8 Temporary Reductions Explained
- How a Realtor's CMA Strengthens Your Case
- LA County Assessor Office Locations
- Frequently Asked Questions
How LA County Property Taxes Actually Work (Prop 13 Explained)
California's property tax system operates under Proposition 13, passed in 1978. Under Prop 13, your property is assessed at its base year value, which is the fair market value at the time of purchase or new construction. That base year value can increase by a maximum of 2% per year for inflation, regardless of how much the market actually moves.
This is why a homeowner who bought in South Pasadena in 1990 for $300,000 might have an assessed value around $600,000, even though their home is now worth $1.5 million. Their property tax is based on the adjusted base year value, not the current market value. This system protects long-term homeowners from being taxed out of their homes.
But the system works both ways. If property values decline below your factored base year value, you are still being taxed at the higher number unless you take action. The Assessor's office does review values proactively in some cases, but they process 2.6 million parcels. Many overassessments slip through.
Your base year value is established when you purchase or when new construction is completed. Each year, the Assessor adds up to 2% for the inflation factor (CPI, capped at 2%). The result is your "factored base year value." Your property tax is approximately 1% of this factored value, plus any voter-approved bonds and special assessments (which typically add 0.25% to 0.50%).
Not sure what your current assessed value is? We can look it up for you in 60 seconds.
💬 Text Your Address to (213) 262-5092When You Should Appeal Your Property Tax Assessment
Not every homeowner should file an appeal. You have valid grounds in three specific situations, and understanding which applies to you determines your strategy and evidence.
Situation 1: Decline in Value (Prop 8 Claim)
If your property's current fair market value has dropped below the factored base year value, you are overpaying. This commonly happens during market downturns, but it also occurs in localized situations. If your Monrovia home backs up to a new freeway sound wall, if there is environmental contamination near your Temple City property, or if your neighborhood has experienced a cluster of foreclosures or distressed sales, your market value may be below the assessed value.
Situation 2: Recent Purchase Overassessment
When you buy a home, the Assessor resets the base year value to your purchase price (or the market value, whichever is lower). But the Assessor also sends a supplemental assessment covering the difference between the previous owner's assessed value and the new base year. If the supplemental assessment is higher than your actual purchase price, or if you received seller concessions that were not reflected, you have grounds to appeal.
I see this frequently in the SGV. A buyer purchases a San Gabriel home for $850,000 with $15,000 in seller credits, but the supplemental assessment is based on $865,000. That $15,000 difference costs the buyer roughly $150 per year in excess taxes, every year, until corrected.
Situation 3: Assessor Error
The Assessor's records may contain incorrect property characteristics. Wrong square footage, incorrect lot size, phantom bedrooms, or a pool that does not exist. These errors inflate your assessed value. Check your property profile on assessor.lacounty.gov and compare every line item to reality.
If your home's current market value is above your factored base year value, an appeal will not help. Prop 13 is already capping your taxes below market value. An appeal can only bring your assessment down to current market value, not below it. If your Pasadena bungalow is assessed at $650,000 but worth $1.1 million, Prop 13 is already saving you thousands. Do not file.
Critical Deadlines: The Filing Window You Cannot Miss
LA County has strict filing deadlines for property tax appeals. Miss them and you forfeit your right to appeal for that entire tax year. No exceptions.
The Assessment Appeals Board receives tens of thousands of applications. If you file close to the November 30 deadline and your application has any errors or missing information, there is no time to correct and refile. File in July or August. Give yourself a cushion. Late filings are rejected without review.
For supplemental assessments (the bill you receive after buying or completing new construction), the filing deadline is 60 days from the date printed on the supplemental assessment notice. This is separate from the annual filing window. Many first-time buyers in Alhambra and Pasadena miss this 60-day window because they do not realize the supplemental bill is appealable.
Set a reminder or text us now. We will flag your filing deadline and send you a reminder.
💬 Text "Deadline Reminder" to (213) 262-5092Informal Review vs. Formal Appeal: Which Path to Take
You have two options when challenging your assessment. Most homeowners do not realize the informal review exists, and it can save you months of waiting.
| Factor | Informal Review | Formal Appeal (AAB) |
|---|---|---|
| Who Decides | LA County Assessor's staff | Assessment Appeals Board panel |
| Filing Required | No formal filing needed | Application for Changed Assessment |
| Cost | Free | Free |
| Timeline | 30-90 days | 12-24 months |
| Evidence Needed | Comparable sales, photos | Comparable sales, photos, formal presentation |
| Hearing | Informal meeting or phone call | Formal hearing before a panel |
| Binding Decision | No — Assessor can decline | Yes — legally binding |
| If Denied | You can still file formal appeal | You can file judicial appeal (Superior Court) |
| Best For | Clear errors, obvious overvaluation | Disputed values, large reductions |
My recommendation: always try the informal review first. If the Assessor agrees your value is too high, you get a reduction in 30 to 90 days without a hearing. If they decline or offer a reduction you consider insufficient, file the formal appeal before the November 30 deadline. You lose nothing by trying the informal route first.
There is nothing preventing you from requesting an informal review AND filing a formal appeal at the same time. File the formal appeal early in the July-November window to preserve your rights, then pursue the informal review. If the informal review resolves the issue, you can withdraw your formal appeal. If not, your formal appeal is already in the queue.
Step-by-Step: Filing Your Property Tax Appeal
Here is the exact process, from identifying the problem to receiving your refund. I have walked dozens of clients in Pasadena, the SGV, and Greater LA through this process.
Look Up Your Current Assessed Value
Visit assessor.lacounty.gov and search by your property address or Assessor's Parcel Number (APN). Note your current assessed value, the base year, and the factored base year value. Compare this to what comparable homes are actually selling for in your neighborhood.
Determine Your Grounds for Appeal
Is your current market value below the assessed value (decline in value)? Was your supplemental assessment higher than your purchase price? Did the Assessor record incorrect property characteristics? Your grounds determine the type of evidence you need.
Gather Your Evidence
Pull three to five comparable sales within a half-mile radius that closed within six months of the January 1 lien date. Take photos of any deferred maintenance, damage, or negative conditions affecting your property. Get a CMA from your realtor or hire an appraiser. The stronger your evidence, the stronger your case.
Need comparable sales data? We pull CMAs from the MLS for free. Public sites miss half the picture.
💬 Text "CMA Request" to (213) 262-5092Request an Informal Review (Optional but Recommended)
Contact the LA County Assessor's office and request an informal review. Bring your comparable sales, photos, and documentation. Present your case clearly and factually. If the Assessor agrees, your reduction is processed without a formal hearing. If denied, move to Step 5.
File the Application for Changed Assessment
Complete the Application for Changed Assessment and file it with the LA County Clerk of the Board / Assessment Appeals Board. You can file online, by mail, or in person. The filing window is July 2 through November 30. For supplemental assessments, file within 60 days of the notice date. There is no filing fee.
Wait for Your Hearing Date
After filing, the Assessment Appeals Board assigns a hearing date. Expect a 12 to 24 month wait in LA County due to the backlog. During this time, continue paying your current tax bill. Do not skip payments. If your appeal succeeds, you will receive a refund for the overpayment period.
Prepare and Attend Your Hearing
When your hearing date arrives, prepare a clear, organized presentation. Bring printed copies of your comparable sales, photos, and any expert opinions. The Assessor's representative will present their evidence supporting the current assessment. Stay factual, avoid emotion, and present your comparable sales methodically. The panel issues a written decision.
How to Gather Comparable Sales Evidence That Wins
The quality of your comparable sales evidence is the single biggest factor in whether your appeal succeeds or fails. The Assessment Appeals Board has seen thousands of cases. Weak comps get dismissed. Here is what makes comps strong.
The Comparable Sales Selection Criteria
- Location: Within a half-mile radius of your property. Same neighborhood or tract preferred. Cross-freeway comps are weak.
- Recency: Closed within six months of the January 1 lien date. Sales closer to the lien date carry more weight.
- Similarity: Match square footage (within 15%), lot size, bedroom/bathroom count, year built, and overall condition as closely as possible.
- Arm's length: The sale must be between unrelated parties at market terms. Foreclosures, short sales, and REOs may be included if they represent a significant portion of your local market.
- Adjustments: If your comps are not identical (they never are), explain the differences. "Comp 1 has a pool, adding approximately $25,000 in value compared to my property which does not."
Automated valuations from Zillow, Redfin, and similar sites are not accepted as credible evidence by the Assessment Appeals Board. They use algorithms, not actual property inspections. An agent's CMA using closed MLS data or a licensed appraiser's report carries real weight. Online estimates carry none.
We pull MLS comparable sales with full detail: closed price, days on market, seller concessions, condition notes. Free for LA County homeowners.
💬 Text "Property Tax Comps" to (213) 262-5092Include your address and we will send your CMA within 24 hours.
What's Your Home Worth Right Now?
Appealing your property tax? A current market valuation strengthens your case.
Get Your Free Home ValueProp 8 Temporary Reductions: How They Work and When They Reset
Proposition 8, passed in 1978 alongside Prop 13, allows the Assessor to temporarily reduce your assessed value below the Prop 13 factored base year value when the current market value drops below it. This is a temporary reduction, and understanding the "temporary" part is critical.
How Prop 8 Works
Each January 1, the Assessor evaluates your property's current market value. If the market value is below your factored base year value, the Assessor should reduce your assessment to the lower market value. In practice, the Assessor's office does not catch every property that qualifies. This is where filing an appeal comes in.
Prop 8 Example: Arcadia Home
An Arcadia homeowner purchased in 2006 for $900,000 (base year value). With 2% annual increases, the factored base year value by 2026 is approximately $1,330,000. But a localized market downturn has reduced the home's fair market value to $1,150,000. The homeowner is being taxed on $1,330,000 when the property is worth $1,150,000. A Prop 8 decline-in-value claim would reduce the assessed value to $1,150,000, saving roughly $2,160 per year in property taxes.
The Reset: When Your Value Goes Back Up
Prop 8 reductions are not permanent. The Assessor reviews your property's value every January 1. As the market recovers, the Assessor will restore the assessed value, up to (but never exceeding) your original Prop 13 factored base year value. The restoration can happen in one year or gradually over several years, depending on how quickly the market rebounds.
Prop 8 Advantages
- Immediate property tax savings during a downturn
- No cost to file
- No risk (taxes cannot increase from filing)
- Applies to all property types in LA County
- Assessor sometimes applies proactively
Prop 8 Limitations
- Reduction is temporary, not permanent
- Value restored as market recovers
- Assessor can restore in a single year
- You must prove market value is below assessed
- Does not change your base year value
How a Realtor's CMA Strengthens Your Property Tax Appeal
A Comparative Market Analysis from a licensed real estate agent is one of the strongest pieces of evidence you can bring to a property tax appeal. Here is why it outperforms everything else you can find online.
What a CMA Includes That Public Sites Do Not
- Actual closed sale prices from the MLS (not estimates or asking prices)
- Days on market showing how long properties sat before selling (longer = weaker market)
- Price reductions documenting how far sellers dropped from original list price
- Seller concessions such as credits for repairs, closing costs, or rate buydowns that reduce the effective sale price
- Property condition notes from agent remarks that public sites do not display
- Adjustments for differences in square footage, lot size, upgrades, and condition
When I prepare a CMA for a client's property tax appeal in the SGV, I am pulling data that the Assessor's office may not have. The MLS contains seller concession details, repair credits, and agent notes about property condition that the Assessor's automated systems miss entirely. A home that closed at $950,000 with $30,000 in seller credits has an effective sale price of $920,000. The Assessor sees $950,000. I see $920,000.
In my experience, homeowners who present a professional CMA or appraisal at their hearing achieve favorable outcomes at a significantly higher rate than those who walk in with Zillow printouts. The Assessment Appeals Board wants to see MLS data, not algorithms. A realtor's CMA gives you the same quality of data the Assessor's own staff uses.
We prepare property tax appeal CMAs at no charge for LA County homeowners. We want you paying the right amount, not a dollar more.
💬 Text "Tax Appeal CMA" to (213) 262-5092Include your property address. We will pull the comps within 24 hours.
LA County Assessor Office Locations for Property Tax Appeals
If you prefer to handle your informal review in person or file your Application for Changed Assessment at a physical office, here are the key LA County Assessor locations serving the San Gabriel Valley, Pasadena, and Greater LA area.
Los Angeles, CA 90012
Check assessor.lacounty.gov for current satellite hours
Available 24/7 during the filing window
You can also file by mail: LA County Clerk of the Board, Assessment Appeals, 500 W Temple Street, Room 383, Los Angeles, CA 90012. If mailing, send via certified mail with return receipt to prove your filing date. The postmark date counts as the filing date.
💬 Need Help Finding the Right Office? Text UsQuick Reference: Property Tax Appeal Cheat Sheet
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Appealing your property tax? A current market valuation strengthens your case.
Get Your Free Home ValueFrequently Asked Questions
What is the deadline to appeal my property tax assessment in LA County?
The annual filing window runs from July 2 through November 30. For supplemental assessments (received after a purchase or new construction), you have 60 days from the date on the supplemental notice. Missing either deadline forfeits your right to appeal for that tax year.
What is a Prop 8 temporary reduction?
Proposition 8 allows the Assessor to temporarily reduce your assessed value below the Prop 13 base year value when your property's current market value drops below it. The reduction is reviewed annually and restored as the market recovers, up to your original factored base year value.
What is the difference between an informal review and a formal appeal?
An informal review is a direct conversation with the Assessor's office. No hearing, no formal record. A formal appeal is filed with the Assessment Appeals Board, guarantees a hearing before a panel, and results in a binding decision. The informal review is faster but the Assessor can decline with no recourse.
How much does it cost to file a property tax appeal?
Filing is free. There is no fee to submit an Application for Changed Assessment. If you hire a property tax appeal firm, they typically charge 25 to 40 percent of the first year's tax savings, paid only if the appeal succeeds. If you gather your own evidence or use a realtor's CMA, the entire process costs nothing.
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💬 Text Your Question to (213) 262-5092Can a realtor help me appeal my property tax assessment?
Yes. A realtor provides a Comparative Market Analysis with MLS closed sale data, days on market, seller concessions, and property condition notes. This is one of the strongest types of evidence the Assessment Appeals Board accepts and far more credible than online estimates from Zillow or Redfin.
What evidence do I need for a property tax appeal?
The strongest evidence includes three to five comparable sales within a half-mile that closed within six months of the January 1 lien date, photos of deferred maintenance or damage, a realtor CMA or professional appraisal, and records of environmental issues. Comps should match your property in square footage, lot size, bedrooms, and condition.
What happens if I lose my property tax appeal?
Your assessed value stays the same. Your taxes do not increase as a result of filing. There is no penalty. You can file again the following year. You also have the option to file a judicial appeal in Superior Court within six months, though this is rarely cost-effective for residential properties.
How long does the LA County property tax appeal process take?
The formal appeal process takes 12 to 24 months after filing due to the LA County backlog. During this time, you pay your current bill and receive a refund if the appeal succeeds. The informal review process is much faster, typically resolved within 30 to 90 days.
Related Homeowner Resources
Stop Overpaying Your Property Taxes
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