A higher property tax bill can feel mysterious because several different numbers may change at once. Your assessment notice may show market value, assessed value, taxable value, exemptions, and local tax rates. Those figures are related, but they are not the same thing.
What are the most common reasons property taxes go up?
The most common causes include a higher estimated market value, a reassessment after a sale or transfer, changes to exemptions, newly recorded improvements, local millage or tax-rate changes, and corrections to a prior assessment. In some jurisdictions, taxable-value caps can also reset after ownership changes.
Start by comparing the new notice with the prior year. Identify exactly which number changed. If market value increased sharply but the tax rate stayed roughly the same, your focus is likely the valuation. If the value changed only slightly but the tax bill climbed, look more closely at tax rates and exemptions.
Could the assessor have incorrect information?
Yes. Property record cards can contain errors involving square footage, finished basements, bathrooms, garages, lot size, condition, construction quality, or improvements. A factual error can affect the assessor’s valuation model before comparable sales are even considered.
Request or review the property record used by the assessor. Compare it to your home as it actually existed on the relevant valuation date. Take photographs and gather documents for anything that is materially wrong.
How do comparable sales affect an assessment?
Assessors commonly rely on market data to estimate value. If your assessment appears above market, recent sales of genuinely similar properties can be useful evidence. Strong comparables are close in location, property type, size, age, condition, and sale date.
A single lower-priced sale is rarely enough. A small group of well-matched sales, paired with a clear explanation of differences, usually tells a more persuasive story.
When should you consider an appeal?
Consider an appeal when the assessor’s value appears materially higher than a supportable market value, when the record card contains significant errors, or when a qualifying exemption may have been omitted. Deadlines and procedures differ by state and county, so confirm the rules for your property before relying on any general strategy.
Use the county finder on PropertyTaxBook.com to reach local assessment information, then organize the notice, record card, comparable sales, photographs, repair estimates, and other evidence before filing.
Read Lowering Your Property Tax in America for a practical framework for reviewing assessments, finding evidence, and preparing an appeal. View the book on Amazon →
Frequently asked questions
Property tax FAQ
Why can property taxes increase even if I did not improve my home?
Your taxable value or local tax rate may change even when you make no improvements. Market-based reassessments, expiring exemptions, millage changes, and local rules can all affect the final bill.
Does a higher assessment always mean the tax bill rises by the same percentage?
No. The relationship between assessed value and the final tax bill depends on local taxable-value rules, exemptions, caps, and tax rates.
What should I check first if my property taxes jumped?
Compare the new notice with last year, verify the property record card, review exemptions, and determine whether the assessor is using a value that exceeds what the property could reasonably sell for.
Property Tax Book
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Lowering Your Property Tax in America gives property owners a practical framework for reviewing an assessment, gathering evidence, preparing a filing, and presenting a focused case.
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