LA County property tax assessment: how it works and how to fight it

Last updated 2026-07-09

How does LA County set your property tax assessment?

LA County values every taxable property in the county, about 2.6 million parcels in all ^[1]. The rule that governs almost all of it is Proposition 13, passed by California voters in 1978. Prop 13 caps your assessed value at the price you paid (your "base year value") and holds annual increases to no more than 2%, or the change in the California Consumer Price Index, whichever is lower ^[2].

So say you bought your house in 2015 for $800,000. Your assessed value today is probably somewhere around $900,000 to $950,000, depending on how the CPI factor landed each year. It is not what your neighbor just sold for. It is not a fresh market appraisal. That distinction matters more than almost anything else in this article, and plenty of homeowners never grasp it.

Your base year value resets only when a "change in ownership" or "new construction" triggers a reassessment ^[2]. A normal sale does it. Adding a room does it. Moving your house into certain trusts can do it too, which catches people off guard. After a trigger event, the Assessor sends a Notice of Supplemental Assessment, separate from your annual bill.

Even if you haven't sold, the Assessor still has to check whether market value has fallen below your Prop 13 value. California Revenue and Taxation Code Section 51 requires enrolling whichever is lower: the Prop 13 factored base year value or current market value ^[3]. This is the "decline in value" review, also called a Prop 8 reassessment. In a down market, you can ask for one.

What is the actual property tax rate in LA County?

Your bill is more than the 1% base rate. The 1% goes to the general fund, but the total effective rate in LA County usually lands between 1.2% and 1.3% of assessed value once you add voter-approved bonds, special assessments, and Mello-Roos community facilities district charges ^[4].

Here is how the pieces stack up:

Component	Typical Rate
General 1% levy (Prop 13 base)	1.000%
K-12 school bonds (varies by district)	0.05% to 0.15%
Community college bonds	0.02% to 0.08%
City/county debt service bonds	0.05% to 0.15%
Total effective rate (approximate)	1.18% to 1.30%

Mello-Roos CFD charges work differently. They're a flat dollar amount, not a percentage, and they show up as a line item on your bill. They're legal as long as the district existed before you bought. You can't fight them at the Assessment Appeals Board because they aren't ad valorem taxes.

Run the numbers on a $900,000 assessment at a 1.25% effective rate and you get about an $11,250 annual bill. That's before exemptions. The Homeowners' Exemption knocks $7,000 off your assessed value, worth roughly $70 a year ^[5]. Small. But it's free, and a lot of people never claim it.

When does LA County reassess your property?

Three things in California law send the Assessor back to reassess your property at current market value ^[2].

A change in ownership is the first. A sale is the obvious case. But partial transfers, adding a co-owner who isn't your spouse, moving title into an LLC, and certain trust changes all count. When a deed gets recorded, the Assessor mails a Preliminary Change of Ownership Report (PCOR). Fill it out correctly. Mistakes here follow you.

New construction is the second. A new structure or a substantial addition gets valued at its construction cost. The rest of the property keeps its old base year value, so only the new part gets reassessed. Add a $200,000 ADU and your assessed value climbs by roughly $200,000, not to the full current market value of everything you own.

The third is the annual CPI adjustment, applied every January 1 and capped at 2%. The 2024 factor was 1.02, because the underlying CPI change ran above the cap and got trimmed to the 2% ceiling ^[6]. The value on your bill reflects the previous January 1 lien date.

Here's the one people miss. Death of an owner can be a change-in-ownership event. Proposition 19, which passed in November 2020 and took effect February 16, 2021, tightened parent-to-child and grandparent-to-grandchild transfers hard ^[2]. If you inherited after that date, the property may have been reassessed to market value unless you moved in as your primary residence and met the other conditions.

How do you read your LA County assessment notice?

The Assessor mails annual assessment notices in the summer, usually July or August, and the clock to appeal a supplemental runs 60 days from the date on that notice ^[7]. The notice shows three numbers you should know how to read.

The "Prior Year Value" is what you were assessed at last year. The "Current Year Value" is the new figure, including the annual CPI bump. If a reassessment event happened (you bought, you built, or the Assessor caught a prior-year escape assessment), a third figure shows the new base year value.

The number that drives your tax bill is the "Net Assessed Value" after exemptions. For most homeowners that's the assessed value minus the $7,000 Homeowners' Exemption. Multiply what's left by roughly 1.25% and you're close to your annual tax.

If you just bought and the value on the notice is higher than your purchase price, dig into it. The Assessor is supposed to enroll your purchase price as the base year value. These discrepancies happen when a sale isn't recorded cleanly or when the PCOR was filed wrong. You can contact the Assessor's Change of Ownership unit and fix a factual error without filing a formal appeal at all.

What are the grounds to appeal your LA County assessment?

There are three main grounds for an appeal to the LA County Assessment Appeals Board ^[7].

The first, and the most common for recent buyers, is that your property's market value on January 1 (the lien date) was lower than the assessed value. You need sales comps from that lien date, not today's sales. The Board looks at similar closed sales from roughly October through April around that date.

The second is a base year value error. If the Assessor recorded the wrong purchase price, treated a transfer as a change of ownership when it wasn't, or used the wrong valuation method, you can challenge the base year itself. These are more technical and sometimes call for professional help, but they win on the facts.

The third is a new construction valuation dispute. If the Assessor's estimate of your addition is off, fight it with contractor invoices, permits, and comparable construction costs.

Decline in value (Prop 8) claims are the practical target for most homeowners. If comparable homes in your neighborhood sold for less than your current assessed value between October and April, you have a case worth pursuing. The Assessor's data is public, and you can pull it yourself.

One thing worth knowing: you can file a decline in value review straight with the Assessor's Office, no formal appeal required. If they agree and cut your value, you're done. If they don't, the formal appeal is still there as a backstop, as long as you filed it before the deadline.

What is the LA County assessment appeal deadline and process?

The regular filing window for most residential property opens July 2 and closes November 30 each year ^[7]. This is the standard period for non-unique property. You file with the LA County Assessment Appeals Board, not the Assessor.

There's a separate window for supplemental and calamity relief. If the Assessor mails you a Supplemental Assessment Notice (from a sale or new construction), you have 60 days from the notice date to appeal, no matter where you are in the July-to-November window.

The filing fee is $30 per parcel for residential property ^[7]. You submit the application online or by mail to the Assessment Appeals Board. Once it's filed, the Board schedules a hearing, and in LA County that can take 12 to 24 months given the caseload. Your appeal sits pending the whole time. Win it, and any overpaid taxes come back to you with interest.

At the hearing you present evidence, the Assessor's representative presents theirs, and a three-member panel decides. Represent yourself if you want. The rules are laid out in the California State Board of Equalization's Publication 30, which explains the process in plain language ^[8].

A practical tip: the Assessor often agrees to a stipulated value before the hearing. Filing the appeal starts that conversation. Many cases settle before anyone sits in a hearing room. That's no reason to skimp on evidence, though. The Assessor's staff reads exactly what you filed, and a weak package invites a lowball counter.

Want to do this yourself and skip the contingency firms that charge 25% to 50% of your first year's savings? A structured DIY approach handles straightforward residential cases fine. The TaxFightBack DIY appeal kit walks you through pulling comps, filling out the application, and building your hearing presentation, and you keep every dollar you save.

What exemptions can reduce your LA County property taxes?

Several exemptions matter, and most of them make you apply.

The Homeowners' Exemption takes $7,000 off assessed value (about $70 a year) and applies to your primary residence once you file the first claim ^[5]. File it once and it renews on its own. If you moved and never updated it, check whether it's still stuck on your old address.

The Disabled Veterans' Exemption is the big one. A veteran with a 100% service-connected disability can exempt up to $161,083 of assessed value (the 2024 figure, indexed each year), and the low-income version reaches up to $241,627 ^[9]. That's real money, $2,000 to $3,000 or more a year, and hardly anyone who qualifies claims it.

California's Property Tax Postponement program lets qualifying seniors (62 or older, household income under $49,017) defer property taxes at 7% annual interest, repaid when the home sells or transfers ^[10]. It's a loan from the state, not a reduction, but it keeps someone on a fixed income from getting forced out.

Church, nonprofit, and welfare exemptions exist for qualifying organizations. If part of your home serves a qualifying purpose, read the Assessor's guidance before you assume you don't qualify.

Proposition 60/90 used to let seniors carry their base year value to a replacement home. Prop 19 replaced it for transfers after April 1, 2021. Now seniors 55 or older, severely disabled persons, and disaster victims can move their base year value to a new home anywhere in California, up to three times, with an upward adjustment if the new home costs more than the old one ^[2]. Planning to downsize or relocate? Understand this before you close.

How does LA County compare to other California and national counties?

Prop 13 keeps LA County assessed values well below market in a lot of neighborhoods, which is both the appeal and the headache. Somebody who bought in 1995 might sit at a $300,000 assessed value on a house worth $1.5 million today. Their annual bill runs around $3,750. A neighbor who bought last year pays about $18,750 on the same kind of house. That gap is baked into California law, and the Assessment Appeals Board can't touch it.

Orange County runs on the same Prop 13 rules. If you're comparing your case to OC property tax, the mechanics are identical, though the Assessor and the appeals board are separate offices.

Oregon works differently. Multnomah County (Portland) assesses at market value with a 3% annual cap on assessed value growth under Measure 50. Its effective rates are lower, roughly 0.85% to 1.05%, but the assessed value sits much closer to market, so the actual bill often ends up near LA's. Clark County property tax in Nevada also uses market-value assessments under a different cap structure.

Pennsylvania's Luzerne County bases assessments on a fixed base year and has gone long stretches without reassessing. That creates the same drift from market value that Prop 13 does, but without a legal cap on how much values jump when a reassessment finally happens. Different risk entirely for owners.

The short version: Prop 13 shields long-term LA owners from runaway bills but does almost nothing for recent buyers, who are already at market value and are the ones most exposed to an over-assessment.

What evidence do you need to win an LA County assessment appeal?

The heart of a residential appeal is comparable sales, and you want to present them the way an appraiser would: similar size, age, condition, and location, sold within about six months of the January 1 lien date you're disputing.

Pull your comps from the LA County Assessor's parcel data, the State Board of Equalization's sales data, or a public real estate database. Three to five strong comps beat ten weak ones. Each comp should list the address, sale date, sale price, square footage, lot size, and condition. Adjust for differences (your house has a pool, the comp doesn't). The Board expects that.

Beyond comps, you can bring a full appraisal from a licensed California appraiser. One runs $400 to $800 for a typical single-family home and carries real weight with the Board. On a high-value property where the potential savings are large, it's almost always worth it. On a median LA County home the math is tighter, but a good appraisal still beats a stack of printed Zillow pages.

For a new construction dispute, use contractor invoices, building permits, and photos of the actual condition. If the Assessor pegged your ADU at $250,000 and your contractor billed $180,000, that gap is your case.

For a base year value dispute, your purchase contract, your ALTA or HUD-1 settlement statement, and the recorded deed are the core documents. If the sale had a non-arm's-length element (related party, foreclosure), document it, because it changes how the Assessor should treat the price.

Presentation counts. Board members hear dozens of cases a day. A one-page summary with the assessed value, your estimated market value, and your top three comps in a table gets you further than a rambling story. See our values assessment guide and the property assessment value overview for how boards weigh evidence.

How do I look up my LA County property assessment records?

The LA County Assessor runs a public portal (assessorportal.assessor.lacounty.gov) where you can pull any parcel by address or APN, the Assessor Parcel Number ^[1]. You'll see the current assessed value, the base year value, any exemptions applied, and the ownership history.

The APN is the key to everything in the appeals process. It's on your tax bill, your assessment notice, and the portal. Keep it somewhere you can find it.

For comps, the Assessor also publishes sales transaction data that beats consumer sites in one way: it includes all recorded deeds, more than MLS listings. The State Board of Equalization publishes county-level assessment ratio studies too, if you want to see how far assessed values drift from market in specific areas ^[8].

Your actual bill comes from the LA County Treasurer and Tax Collector, a separate office from the Assessor. The Assessor sets the value. The Treasurer-Tax Collector calculates the bill and collects the money. Payment question or need a duplicate bill? Go to the Treasurer-Tax Collector. Valuation question? Go to the Assessor.

For a general starting point on pulling records in any county, the property tax lookup guide and our property tax records overview walk through it step by step.

What happens after you file an LA County assessment appeal?

After you file, you get a confirmation, and eventually a notice scheduling your hearing. The Assessment Appeals Board handles thousands of cases a year, so a 12 to 24 month wait is normal ^[7]. During that stretch, pay your tax bill on time. The appeal does not suspend what you owe. A late payment picks up a 10% penalty, and that penalty stings whether you win the appeal or not.

Before the hearing, the Assessor's staff reviews your application. Often they'll reach out about a stipulated (agreed) value. If you're within reasonable range of their number, a stipulation saves everybody time. Accept it or decline it and go to hearing. Your call.

At the hearing you carry the burden of proof on market value appeals. On base year value disputes, the burden flips to the Assessor once you show the enrolled value is wrong. The panel can take your value, the Assessor's value, or anything in between.

Win, and the Assessor adjusts the roll while the Treasurer-Tax Collector refunds any overpayment with interest at the county pool rate (roughly 0.5% to 1% a year lately). Lose, and you can appeal to Superior Court under California Revenue and Taxation Code Section 5140, though that rarely pays off on a residential case because legal costs run past the savings.

For what to do once you have a result, see property tax explained: how it's set and how to appeal it.

Should you hire a property tax agent or appeal yourself in LA County?

Contingency firms in LA County usually charge 25% to 50% of your first year's tax savings. On a $2,000 saving, that's $500 to $1,000 in fees, and some contracts auto-renew year after year.

For a straightforward residential appeal where your evidence is solid comps and your case is a clean market value decline, there's no reason you can't run it yourself. The Board allows self-representation. The filing isn't complicated. The evidence standard is well within reach of anyone who can read a real estate listing.

Bring in help for the hard cases: complex business entities, income-producing commercial property, or a base year dispute with legal wrinkles (a trust transfer that may or may not be a change of ownership). Those have more moving parts and higher stakes, and a licensed property tax agent or a real estate attorney who works this area regularly earns the fee.

My honest read on contingency firms: they make sense when you truly don't have the time, the property value is very high, or the legal complexity is beyond a non-specialist. For a typical LA County single-family home, you can match their result in a few hours and keep 100% of the savings.

The TaxFightBack DIY appeal kit is built for exactly that homeowner, the one who got a bad assessment and doesn't want to hand 30% of the savings to a firm. It includes comp-pulling templates, a walkthrough of the appeal application, and a hearing prep guide written for California's rules.

Frequently asked questions

What is the deadline to appeal my LA County property tax assessment?

For most residential property, the annual window runs July 2 through November 30. If you got a Supplemental Assessment Notice (from a sale or new construction), you have 60 days from the date on that specific notice, regardless of the annual window. The filing fee is $30 per parcel. Miss the deadline and you wait for the next filing period.

How do I file an assessment appeal in LA County?

Submit an Assessment Appeal Application to the LA County Assessment Appeals Board, online through their portal or by mail to 500 W. Temple Street, Los Angeles. Include your APN, the value you believe is correct, and a short explanation of your grounds. No attorney required. The $30 fee applies to residential parcels. The Assessor's staff reviews your filing before any hearing gets scheduled.

Can I appeal if my house hasn't been recently sold?

Yes. You can appeal on decline in value (Prop 8) grounds if the current market value of your property on January 1 is lower than your current assessed value. You provide comparable sales showing what similar homes sold for around that date. This route is open every year, more than after a purchase.

How does Proposition 13 affect my LA County assessment?

Prop 13 caps your assessed value at your purchase price (the base year value) and limits annual increases to the lesser of 2% or the California CPI change. Your value resets to market only when you sell, finish new construction, or trigger a change in ownership. It protects long-term owners from rising markets but leaves recent buyers assessed at full purchase price right away.

What is the Homeowners' Exemption and how do I claim it?

The Homeowners' Exemption cuts your assessed value by $7,000, worth about $70 a year, and it applies to your primary residence. File a claim with the LA County Assessor once and it renews automatically. If you moved and didn't update it, it may still be sitting on your old address. Check the Assessor's portal to confirm it's on your current property.

How long does an LA County assessment appeal take?

Expect 12 to 24 months from filing to hearing, given the Assessment Appeals Board's caseload. Keep paying your tax bill on time while the appeal is pending. If you win, you get a refund with interest on the overpaid amount. Many cases settle by stipulation before the hearing, which can shorten the timeline considerably.

What comparable sales evidence should I bring to my appeal hearing?

Bring three to five closed sales of properties like yours in size, age, condition, and location, sold within about six months of the January 1 lien date. Each comp should show address, sale date, price, square footage, and lot size. Note any material differences between your property and the comps. A licensed California appraisal carries real weight and runs $400 to $800.

Does a new ADU or room addition trigger a reassessment in LA County?

Yes, new construction triggers a supplemental reassessment. But only the value of the new construction gets added to your roll. Your existing structure keeps its current base year value. Add a $200,000 ADU and your assessed value rises by roughly $200,000, not to the full market value of the whole property. You can appeal the Assessor's construction valuation within 60 days of the supplemental notice.

What is Proposition 19 and how does it affect inherited property in LA County?

Prop 19 took effect February 16, 2021, and tightened parent-to-child transfer exclusions. Now an inherited property avoids reassessment only if the heir moves in as a primary residence within one year and claims the Homeowners' Exemption, and the exclusion is capped at $1 million over the property's assessed value. Transfers that miss these requirements get reassessed to current market value.

Can seniors transfer their low property tax base to a new home in California?

Yes. Under Prop 19, homeowners 55 or older, severely disabled persons, and victims of declared disasters can transfer their base year value to a replacement home anywhere in California, up to three times in their lifetime. If the replacement costs more than the original, the base year value adjusts upward by the difference. That can save real money when downsizing in a high-value market like LA.

How is the LA County property tax assessment different from Multnomah County or Luzerne County?

Multnomah County (Oregon) assesses at market value with a 3% annual cap under Measure 50, so values track closer to market but rates are lower. Luzerne County (Pennsylvania) uses periodic reassessments with no continuous cap, which creates drift between cycles. LA County's Prop 13 pegs value to purchase price indefinitely, producing the largest gap between assessed and market value of any major California county over time.

What is a supplemental assessment and why did I get one?

A supplemental assessment reflects a mid-year change in your base year value, usually from a sale or new construction. The Assessor calculates the difference between the old and new assessed values, prorates it for the remaining fiscal year, and mails a supplemental bill. You have 60 days from the notice date to appeal. Supplemental bills come separately from your regular annual tax bill.

What is the Senior Citizens' Property Tax Postponement program in California?

California's Property Tax Postponement program lets homeowners 62 or older with household income below $49,017 defer property taxes while they live in the home. The state pays the taxes and records a lien; the deferred amount plus 7% annual interest is repaid when the home sells or transfers. It doesn't reduce your tax, but it prevents a forced sale for someone who can't cover the current bill.

Is it worth hiring a property tax agent or contingency firm for an LA County appeal?

For a standard residential appeal with a clear market value argument, you can likely handle it yourself and keep 100% of the savings instead of paying a firm 25% to 50% of the first year's reduction. Contingency firms make more sense for high-value commercial property, base year disputes with legal complexity, or when you genuinely lack the time to pull and analyze comps. For most single-family homeowners, the DIY math is strongly in your favor.

Sources

1. LA County Assessor's Office, About the Office: The LA County Assessor is responsible for valuing approximately 2.6 million taxable parcels in LA County.
2. California State Board of Equalization, Proposition 13 Overview: Prop 13 caps assessed value at purchase price with a 2% or CPI annual limit; reassessment triggers include change in ownership and new construction; Prop 19 replaced Prop 58 for parent-child transfers effective February 16, 2021.
3. California Revenue and Taxation Code Section 51, Decline in Value: R&T Code Section 51 requires the Assessor to enroll the lesser of the Prop 13 factored base year value or current market value each year.
4. LA County Treasurer and Tax Collector, Understanding Your Property Tax Bill: The total effective property tax rate in LA County typically runs 1.18% to 1.30% when voter-approved bonds and special assessments are included above the 1% base.
5. LA County Assessor's Office, Homeowners' Exemption: The Homeowners' Exemption reduces assessed value by $7,000, saving approximately $70 per year, and is available to owner-occupied primary residences.
6. California State Board of Equalization, CPI Adjustment Factors: The Prop 13 annual inflation factor is capped at a 2% maximum increase when the underlying CPI change exceeds that ceiling.
7. LA County Assessment Appeals Board, Filing Information: The regular appeal filing period runs July 2 through November 30; supplemental notices carry a 60-day appeal deadline; the residential filing fee is $30 per parcel.
8. California State Board of Equalization, Publication 30: Residential Property Assessment Appeals: Publication 30 explains the procedures, burden of proof, and evidence standards for California assessment appeal hearings.
9. LA County Assessor's Office, Disabled Veterans' Exemption: Veterans with 100% service-connected disability can exempt up to $161,083 of assessed value as of 2024 (indexed annually); low-income variant can exempt up to $241,627.
10. California State Controller's Office, Property Tax Postponement Program: California's Property Tax Postponement program allows homeowners 62 or older with income below $49,017 to defer property taxes at 7% annual interest, repaid upon sale or transfer.