Tax assessed value is what your local government decides your property is worth for tax purposes — and it is usually lower than what you could sell it for

When you own a home or land, your local assessor assigns it a dollar value. That value is not what a real estate agent would list it at, and it is not what you paid for it. It is the value the government uses to calculate your property tax bill. If your assessed value is $300,000, your property tax is a percentage of that $300,000, not of the actual market price.

The assessed value matters because it directly determines how much you owe in property taxes each year. A higher assessed value means a higher tax bill. A lower one means you pay less. Understanding how assessors arrive at that number — and whether you can challenge it — can save you hundreds of dollars annually.

Key Takeaways

  • Tax assessed value is set by your local assessor and is used to calculate property taxes, not to reflect what your home would sell for today.
  • Assessors typically use comparable sales, income approach, or cost approach to estimate value, depending on the property type and local practice.
  • Assessed values are usually lower than market value because many states cap how much the assessment can increase each year, even if the market rises.
  • You can challenge your assessed value through a formal appeal process in your county or municipality, usually with a important date in spring or early summer.
  • Errors in property records — wrong square footage, missing improvements, or incorrect lot size — are common reasons assessments are too high.

How assessors decide what your property is worth

Your local assessor's office uses three main methods to estimate value. The sales comparison approach looks at what similar homes in your area sold for recently. If three comparable homes sold for $320,000, $310,000, and $330,000 in the past year, your home might be assessed at $320,000. This method works best for residential properties where sales data is plentiful.

The cost approach adds up what it would cost to rebuild your home from scratch, then subtracts depreciation for age and wear. An assessor might estimate the land is worth $80,000, the structure would cost $250,000 to rebuild new, subtract $30,000 for age and condition, and arrive at $300,000. This method is common for newer homes or properties where sales comparables are scarce.

The income approach applies mainly to rental properties and commercial real estate. An assessor estimates how much rent the property could generate annually, then calculates what that income stream is worth. A building that rents for $24,000 per year might be assessed at $300,000 if the local market values rental income at a 8 percent return.

Most assessors use a combination of these methods and update assessments every one to four years, depending on your state and county. Some jurisdictions reassess annually; others do it every three years. The frequency varies widely.

Why assessed value is usually lower than what your home would sell for

In many states, the law limits how fast an assessed value can rise each year, even if the housing market is booming. California's Proposition 13, for example, caps annual increases at 2 percent unless the property changes hands. If your home was assessed at $250,000 five years ago, it might still be assessed at $275,000 today even though comparable homes now sell for $350,000. The assessed value lags behind market reality.

Other states use a lower assessment ratio — they assess all properties at a percentage of market value rather than full value. A state might assess residential property at 50 percent of market value, so a home worth $400,000 on the market gets assessed at $200,000 for tax purposes. This keeps tax bills manageable but means the assessed value will always be lower than what you could sell the home for.

Some jurisdictions also explore different assessment ratios to different property types. Agricultural land might be assessed at 30 percent of market value while residential land is assessed at 60 percent. These policies vary by state and sometimes by county within a state.

How to find your property's assessed value

Your assessed value is public record. The easiest way to find it is to visit your county assessor's website — search "[your county] assessor" plus "property search" or "assessment records." Most counties now offer free online lookup tools where you enter your address and see the assessed value, property description, and recent assessment history.

If your county does not have an online tool, you can visit the assessor's office in person or call them. Bring your address and property identification number if you have it. The assessor's office will give you a copy of your assessment record, which shows the assessed value, the land value, the building value, and notes about the property's features.

You can also request a formal assessment notice, which your county mails to property owners periodically — often every two to four years. This notice shows the new assessed value and usually includes information about how to appeal if you disagree.

Common errors that make assessed values too high

Assessors work from public records that are sometimes outdated or wrong. A property record might list your home as 2,500 square feet when it is actually 2,200. It might show four bedrooms when you have three. It might not reflect a major renovation or addition you made. These errors directly inflate the assessed value.

Another common mistake is the assessor recording the wrong lot size or missing a boundary line correction. If your lot is listed as 0.5 acres when it is actually 0.35 acres, the assessment will be higher than it should be. Zoning errors — the property marked as commercial when it is residential — can also skew the value significantly.

Some assessments include improvements that no longer exist or that were never actually built. A deck or garage listed in the records but not present on the property will inflate the value. Checking your assessment record against what actually exists on your land is the first step in spotting these errors.

How to challenge your assessed value

Most counties have a formal appeal process, usually called an assessment appeal, property tax appeal, or assessment review. The process typically starts with filing a written objection with your county assessor or a board of review. You will need to submit this objection by a specific important date — often in spring or early summer, though dates vary by county. Missing the important date usually means you cannot appeal that year.

To make your case, gather evidence. Bring a copy of your assessment record, photos of your property, documentation of any errors in the records, and comparable sales data if you have it. If your assessed value is $320,000 but three nearly identical homes in your neighborhood sold for $280,000, $285,000, and $290,000 in the past year, that is strong evidence the assessment is too high.

Some counties allow you to present your case in writing; others require an in-person hearing. If you attend a hearing, bring your evidence and be prepared to explain why you believe the assessment is wrong. You do not need a lawyer, though some people hire a property tax consultant or attorney if the stakes are high.

If the assessor or board denies your appeal, many states allow a second level of appeal to a state tax court or similar body. The process and timeline for this second appeal vary by state. Check your county assessor's website or call their office for the specific steps in your jurisdiction.

What happens after your assessment is changed

If your appeal succeeds and your assessed value is lowered, your property tax bill will drop the following year. The reduction applies to the next tax year's bill, not retroactively to past years. If you were overcharged in previous years, you may be able to request a refund, but this depends on your state's rules and how far back you can appeal. Some states allow refunds for the current year only; others allow three to five years back.

A successful appeal does not protect you permanently. Your assessed value can be reassessed and potentially raised again in future years, especially if the housing market rises significantly or if your county conducts a full reassessment cycle. However, if the error was in the property records themselves — wrong square footage or missing boundary line — correcting it should prevent the same mistake from happening again.

Frequently Asked Questions

Is assessed value the same as appraised value?

No. An appraisal is done by a licensed appraiser, usually for a mortgage lender, and estimates what the home would sell for. An assessed value is set by the government for tax purposes and is often lower. You might have an appraisal of $350,000 for a mortgage but an assessed value of $280,000 for taxes.

Can I lower my assessed value by doing nothing to my property?

No. Assessed values are based on what the property is worth, not on how well you maintain it. However, if your property has genuine damage — a roof that needs replacement, a foundation problem — you can document this and use it as evidence in an appeal that the current assessment is too high.

What if I just bought my home — will the assessed value change?

Possibly. Many states reassess property after a sale to reflect the new purchase price. Some states use the sale price as the new assessed value; others use it as one data point. Check your county's reassessment policy. If you bought at a price lower than the previous assessment, you may have grounds to appeal the new assessment.

Do I have to pay property taxes based on the assessed value even if I disagree with it?

Yes, you must pay your property tax bill on time. If you believe the assessment is wrong, you file an appeal to challenge it. Paying the bill does not waive your right to appeal, and a successful appeal can result in a refund for overcharged taxes.

How often should I check my assessed value?

Check it whenever you receive an assessment notice from your county, which is usually every two to four years. You can also check it annually online if your county offers that tool. Catching errors early gives you more time to file an appeal before the important date.