More than half of homeowners pay too much because their property has been wrongly assessed.

Property-tax increases are based largely on rising home values, not the increase of taxes by local governments.  Different formulas are used to figure property taxes, but it all depends on a home's assessed value.  Some jurisdictions use a home's actual market value, while others use a percentage of a property's worth.

The National Taxpayers Union estimates that as much as 60% of taxable property in the United States is overassessed.  But only half of homeowners protest their assessments.  This means many may be paying more in property taxes than necessary.  Many taxpayers don't fight it because they don't understand the process, or because they can't stomach doing the research and providing evidence to prove the assessment is wrong.

If you really don't have the time or desire, hire a property-tax consultant or attorney to do the work.  Many of these consultants charge on a contingency basis, meaning they'll take a percentage of the tax savings if they succeed in lowering your assessment.

Mistakes happen more often than you think.  Many assessors don't even come onto your property to inspect it.  They simply compare a written description of your home with that of similar properties in your neighborhood.  Appraisers also may use historical information that's wrong.  A home's square footage, for example, might have been incorrectly calculated on original construction documents.