How Property Tax Assessments Work

What do the key property tax terms mean?

The property tax system uses a consistent set of terms that are important to understand before examining your tax bill or considering an appeal. The following table defines the core concepts and their relationship to your annual property tax bill.

Step 1: Property Valuation, How Assessors Determine Market Value

County assessors are responsible for establishing the market value of every property in their jurisdiction. For residential properties, they primarily use three valuation approaches:

• Sales Comparison Approach: The most common method for residential properties. The assessor identifies recent sales of comparable properties ("comps") - similar size, age, condition, and location, and adjusts for differences. This approach relies on actual market transactions and is the most direct reflection of fair market value.
• Cost Approach: Estimates the cost to replace or reproduce the property's structures from scratch, then subtracts depreciation. This approach is most reliable for newer construction and unique properties where comparable sales are limited. It accounts for land value separately from building value.
• Income Approach: Used primarily for income-producing properties (apartments, commercial). The assessor capitalizes the property's net operating income into a value estimate. For residential properties, this approach is rarely primary but may factor into multi-family assessments.

Most mass appraisal systems use statistical models that analyze hundreds of sales across a jurisdiction to develop valuation formulas that can be applied consistently to all properties. These models are updated with each assessment cycle.

You can review your property record card, typically available from your county assessor's website, to see the data used in your valuation: recorded square footage, bedroom count, bathroom count, year built, condition rating, and any improvements on record.

Step 2: Assessment Ratios, From Market Value to Assessed Value

Once market value is established, many states apply an assessment ratio to determine the assessed value, the base to which mill rates are applied. States vary dramatically in their assessment ratios:

• full value assessment: Most states, including New York, Texas, and New Jersey, assess at full market value
• Below full value: Some states use fractional assessments, Louisiana assesses residential property at 10% of market value but applies higher mill rates to compensate; Tennessee uses 25%
• Capped increases: California under Proposition 13 caps annual value increases at 2% regardless of market appreciation

Fractional assessment ratios can make it appear that two states have very different mill rates when their effective rates are actually similar. The effective rate, actual annual tax divided by market value, is the most meaningful comparison.

PlainPropertyTax shows effective rates derived from Census ACS data, making this comparison straightforward across all 50 states and the 3,135 counties carrying a current-year rate.

Step 3: Mill Rates, How Tax Rates Are Set Each Year

Mill rates (millage rates) are not static, they are recalculated annually by each taxing authority based on its budget and the total assessed value of all taxable property in its jurisdiction. The formula is: Mill Rate = Required Levy ÷ Total Assessed Value × 1,000.

Most property owners face multiple overlapping mill rates, one from each authority that taxes the property:

• County rate
• Municipal rate
• School district rates: one or more, often the largest single component, typically 40-60% of the total bill
• Special district rates: fire district, library district, hospital district, mosquito control district

Each taxing authority sets its rate independently, and the total applied to your property is the sum of all applicable rates.

A rising real estate market does not automatically increase your tax bill if the mill rate is reduced proportionally. When all properties in a jurisdiction appreciate equally, the total assessed value base increases, allowing authorities to achieve the same levy with a lower mill rate. Your tax bill rises if:

• your property appreciates faster than average
• the required levy increases (higher budgets)
• your exemptions decrease

For where bills actually grew the most, see the counties with the fastest property tax increases between 2020 and 2024.

Step 4: Exemptions, Reducing Your Taxable Value

Exemptions reduce the assessed or taxable value of your property before the mill rate is applied, directly reducing your tax bill. The major categories of exemptions available in most states:

• Homestead Exemption: Reduces assessed value for primary residences. Texas offers a $40,000 deduction from school taxes; Florida exempts $50,000 from assessed value; Georgia exempts $2,000. Most require you to apply and prove the property is your primary residence.
• Senior Citizen Exemption: Additional reductions for homeowners over 65, sometimes with income limits. Texas's over-65 exemption includes a school tax freeze, your school taxes can never increase from the year you turn 65 if you apply. Some states offer senior deferrals, the tax is deferred until the home is sold.
• Veteran and Disabled Veteran Exemptions: Available in most states; disabled veterans often receive full value exemption in several states. Service-connected disability percentage often determines the exemption amount.
• Agricultural / Current Use Exemptions: Working farms, timberland, and open space may be assessed at their agricultural use value rather than development market value, often a fraction of the market rate.
• Circuit Breaker Programs: Some states offer income-tested circuit breakers, property tax credits or rebates for homeowners and renters whose tax burden exceeds a threshold percentage of income.

Step 5: Notice, Payment, and Appeals

The assessment cycle typically follows a predictable annual or multi-year calendar. After the assessor completes valuations, property owners receive a Notice of Assessment showing the new assessed value. This notice comes with an appeal deadline, often 30-90 days from the notice date, that is a hard cutoff. Missing this deadline means accepting the current assessment until the next cycle.

Property taxes are typically paid in one of two ways:

• In a lump sum annually: most common for properties owned outright
• Through an escrow account: managed by your mortgage lender, who collects the estimated annual tax monthly and makes the payment when due

Non-payment leads to penalties, interest, and eventually tax liens and tax sales, counties can and do sell properties for unpaid taxes.

If the assessed value looks high relative to recent comparable sales in the same neighborhood, every US jurisdiction publishes an appeal process with a stated filing deadline. This extract does not store appeal-win rates. See the process guide at How to Appeal Your Property Tax Assessment.

Frequently Asked Questions