Your assessed value is higher than the market value of the property at the time the assessment was made. Bear in mind, the current market value of your property is not relevant; you’re looking at the value 12 to 18 months ago, because that is the typical lag between the assessment date and the date on which you receive your tax bill;
	Alternatively, you can argue that your property was assessed at a disproportionately higher rate than other properties similar to yours in your community; or
	You can contend that the assessors based their calculations on incorrect assumptions about your home, for example, crediting you with a larger lot or more interior space than you actually have.

If you can prove and of these claims (and you will need strong evidence—comparable sales establishing that the assessment was too high, or examples of similar homes with lower assessments), then you should win your request for an abatement on your current tax bill. But forget about challenging past bills; you have only 30 days from the time the tax bill is posted to file an abatement claim with the local board of assessors. If you miss that filing deadline (or fail to pay your tax bill—another requirement to preserve your rights under the abatement process) you forfeit your right to appeal the tax bill.