How California Property Tax Assessments Work - and How to Appeal If You Think Yours Is Wrong
How does Proposition 13 limit my California property taxes?
Under Proposition 13, California assesses your property at its purchase price and caps annual increases in that assessed value at 2 percent, regardless of the real estate market. Your base property tax rate is 1 percent of that assessed value, plus any local voter-approved levies. The cap resets to market value when the property changes ownership or undergoes new construction.
How do I appeal my property tax assessment in California?
To appeal a California property tax assessment, file an Application for Changed Assessment with your county's Assessment Appeals Board before the applicable deadline - typically 60 days from a reassessment notice or by November 30 of the assessment year for routine annual assessments, though exact deadlines vary by county. You'll need comparable sales data or an appraisal supporting your claimed value.
Can my California property tax assessment go down if home values drop?
Yes. Under Proposition 8, if your home's current market value falls below its Proposition 13 assessed value, you can request a temporary reduction from your county assessor. If the market later recovers, the assessor can restore the value, but only up to the Prop 13 base - not above what it would have been under the normal 2 percent annual cap.
What is the California homeowner's exemption and how do I get it?
The California homeowner's exemption reduces your property's assessed value by approximately $7,000, lowering your annual tax bill by roughly $70 at the base 1 percent rate. It applies to owner-occupied primary residences. You apply through your county assessor's office, typically after you purchase a home. The exemption is not automatic - you must file, though you only need to do so once as long as you continue to occupy the property.
What happens to my property tax assessment when I buy a home in California?
When you buy a home in California, the county assessor resets the assessed value to your purchase price - this is called a change-in-ownership reassessment. From that point, annual increases are capped at 2 percent under Proposition 13. This means your tax bill is based on what you paid, not the home's current market value, as long as you own it.
California's property tax system works nothing like most states - thanks to Proposition 13, your tax bill is tied to what you paid for your home, not what it's worth today. That's a genuine protection for long-term homeowners, but it also creates real confusion when a new assessment arrives and doesn't match what you expected. Here's how the system actually works, and what to do if you think your county got the number wrong.
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What Proposition 13 Actually Does to Your Tax Bill
Under Proposition 13, which California voters passed in 1978, your property is assessed at its purchase price when you buy it. After that, annual increases in assessed value are capped at 2 percent per year, regardless of what's happening in the real estate market. That cap holds until the property changes hands or undergoes new construction.
Your annual property tax bill is calculated at 1 percent of that assessed value, plus any voter-approved local levies - bonds for schools, community college districts, and similar measures - that stack on top of the base rate. The total effective rate varies by county and even by parcel, so two houses on the same block can carry meaningfully different bills if they were purchased in different years at different prices.
When you buy a home, the county assessor resets the assessed value to your purchase price. That's called a "change in ownership" reassessment. From that point forward, your base can rise by no more than 2 percent annually under Prop 13, which means a homeowner who bought in 2010 and a buyer who bought the same house last year can face very different tax bills even if the homes are now worth the same amount on the open market.
When Your Assessment Can Go Up - Or Down - Outside the Normal Cycle
Beyond the annual 2 percent cap, assessors can reassess a property upward after a change in ownership or completion of new construction. Significant remodeling, an addition, or a permitted accessory dwelling unit are all examples of new construction that can trigger a partial reassessment of the improved portion of the property.
Less commonly discussed: assessed values can also go down. Under the Proposition 8 provisions passed in 1978 alongside the original measure, if your home's current market value falls below its Prop 13 assessed value, you can request a temporary reduction. This was widely used after the 2008 housing collapse. If the market recovers, the assessor can restore the value back up - but only to the Prop 13 base, not above it.
Assessors in California conduct these reviews annually, and some counties proactively reduce assessments during market downturns. But in a rising market, most homeowners won't see a Prop 8 reduction; their Prop 13 base will simply sit well below actual market value.
How to Read Your Assessment Notice
County assessors typically mail annual assessment notices in the spring or summer. The notice lists your property's assessed value for the coming tax year, broken into land value and improvement (structure) value. It is not a tax bill - the actual bill comes from the county tax collector, usually in the fall.
If there's been a reassessment event, the notice will explain why: a change in ownership, new construction, a Prop 8 value adjustment, or a correction. Read this carefully. The assessment notice is also what starts the clock on your window to appeal, which makes the mailing date the most important date in the process.
How to Appeal Your Property Tax Assessment in California
Every California county has an Assessment Appeals Board - an independent local body, not part of the assessor's office - that hears challenges from property owners. The process is governed by the California State Board of Equalization, and the general framework is the same statewide, though procedures and fees vary by county.
The appeal window is typically either 60 days from the date a reassessment notice is mailed or through November 30 of the assessment year for regular annual assessments, whichever applies to your situation. This is a firm deadline in most counties - missing it generally means waiting until the next assessment year. Check your county assessor's or assessment appeals board website for the exact deadline that applies to your notice, because the calculation differs depending on whether you received a formal reassessment notice or are challenging a routine annual value.
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To file, you submit an Application for Changed Assessment to your county's Clerk of the Board of Supervisors or Assessment Appeals Board. Most counties have this form online. You'll typically need to state the value you believe is correct and provide supporting evidence - recent comparable sales in your neighborhood, a licensed appraisal, photos documenting condition problems, or documentation of an error in the property's recorded characteristics (wrong square footage, wrong number of bathrooms, etc.).
After you file, the board schedules a hearing. You present your case, the assessor's office presents theirs, and the board issues a decision. If the board rules in your favor, your assessed value is adjusted and any overpayment is refunded with interest. You do not need an attorney to appeal, though some homeowners hire a property tax consultant, who typically works on a contingency basis for residential appeals.
What the State Board of Equalization's Role Is
The California State Board of Equalization oversees the standards county assessors use and publishes detailed guidance on assessment practices, property tax exemptions (including the homeowner's exemption worth around $7,000 off assessed value, which reduces your bill by roughly $70 per year at the base rate), and the appeals process. The Board of Equalization does not hear individual residential appeals - those stay at the county level - but its publications are the clearest plain-language explanations of how the system works.
If you believe your county assessor is systematically misassessing properties in a way that affects a class of taxpayers, the Board of Equalization can investigate, but that's a separate and far more complex process than a routine individual appeal.
This is general information, not legal or financial advice. Property tax deadlines, fees, and procedures vary by county and change over time. Verify current appeal deadlines, exemption rules, and assessment practices with your county assessor's office or the California State Board of Equalization at boe.ca.gov.