• Even within the same community, homes in a new subdivision may have higher assessments than comparable properties elsewhere.Huntstock/Brand X Pictures/Getty Images
  
  While state and local governments have the power to impose different types of taxes and fees, many rely predominantly on property taxes to fund basic services like education, public safety and health. All over the country, property taxes may be levied by towns, cities, counties, states and/or other public entities, like utilities and school districts.
  
  Homeowners often question the fairness of their property tax bills. This reflects the complexity of how property taxes are calculated. To help ensure that everyone is treated equitably, individuals or neighborhood groups can challenge assessments, revaluations and tax rates.
  
  

Assessments

• An assessment is the taxable value of a property, determined by a government official called an assessor. Assessors may consider a range of factors including a home's replacement cost, the value of improvements (like a porch or patio), and for how much comparable homes have sold.
  
  But because an assessment is simply an opinion, it may be open to challenge. A homeowner can file an appeal if he has evidence that the assessor has made a mistake or misjudgment -- for example, by incorrectly measuring an addition or overestimating the price of a pool. Depending on state and local rules, there may be many other bases for challenging a property assessment.
  
  

Revaluations

• Sometimes the average property tax bill can differ significantly from one part of a community to another, even on similar homes. This discrepancy is commonly caused by fluctuations in the local real estate market. For example, if houses in a newly developed subdivision are selling at high prices, their owners will likely face higher assessments than owners of comparable properties in older neighborhoods. To make adjustments that are fair to everyone, local governments use a periodic process called revaluation. Homeowners can challenge this process, based on timing or methodology, if it does not appear to correct inequities.
  
  

Tax Rates

• Every taxing authority sets its own tax rate, the amount per $1000 of value charged to each property owner. Also called a millage rate, it is chosen by policymakers to yield what they consider an adequate amount to fund the activities of government. But homeowners can challenge public leaders to trim expenditures so they will need to raise less revenue. Even if the government can't or won't cut spending, it can seek to broaden the tax base -- in other words, to attract more residents or businesses in order to spread the tax burden over a larger number of contributors.