From Boston.com:
Why is it that so few taxpayers try to  reduce their property taxes? As many as 60 percent of US homes may be  overassessed, according to the National Taxpayers Union, but most homeowners  don't know how the process works or that they can appeal.
You are likely to have more success this  year, because in most areas there is a large disparity between assessed  values from the boom years and depressed current market values.
Most likely your home's assessment is  out of date since it is based on an average of local values that may  go back three years. Since the height of the boom market, prices have  declined by 20 to 50 percent.
Appealing your assessment is something  anyone can do, yet it is important to do some preparation work. I have  been able to lower or freeze my home's assessed value several times.
There's often little accountability in  how assessors value your property. They make mistakes, and assessments  may be wildly inconsistent in your community.
Check your home's legal description.  Does it match precisely your house and lot characteristics? There may  be errors in the records on the number of finished rooms, lot size,  and interior square footage.
The second step is to determine whether  you are fairly assessed. You will need to work out whether similar houses  sold at lower prices than your home's current market value. Are there  any local features that will reduce your property's value? Railroads,  highways, landfills, easements, and rezonings (to commercial) count.
You can present these details to your  assessor before you file a formal appeal, but don't expect him to give  you a reduction. Most states have bodies that deal specifically with  real-estate tax appeals at higher levels.
If you don't feel comfortable researching  and filing your own appeal, you can hire an attorney. They are usually  compensated by taking a percentage of your tax savings. Appeal boards  tend to respect the opinion of a certified real-estate appraiser more  than yours. Spend a few hundred dollars to present a recent certified  appraisal.
Be professional and precisely document  your case. Appeals boards are swamped right now. Ocean County, N.J.,  for example, is facing more than 14,000 appeals this year.
Typically, you will have just a few minutes  to make your appeal. Keep in mind you have to meet strict filing deadlines.  Don't expect an immediate reduction in property taxes. Taxing bodies  still have the power to raise levies or float referendums if they need  funds. Your taxes may rise - even in this market.
If the deadline for appeal has passed  this year, start building your case for next year. Definitely mount  a challenge if you are in the highest property-tax states - such as  Massachusetts.
