Once every five years, the town of Andover goes through a “revaluation” process as mandated by state law. Every property is looked at by outside tax assessors, and a new market value is determined, which then becomes that property’s new assessed value.

This year was “re-val year” in Andover, and the results are in. The total assessed value of all Andover properties dropped by approximately 6.2%. Some properties’ assessments dropped by more than that. Some dropped less than that, and some (especially waterfront properties) actually rose.

It’s very easy to get confused by the complex relationships among the tax base, the tax rate, the budget, revenues, the amount to be raised by taxes, and our tax bills. Here are some of the basics to keep in mind when you examine your 2014 Andover tax bill.

• When the total tax base goes down (as it did this year), the tax rate must rise in order to raise the same amount of tax revenue. That simple mathematical relationship accounts for 6.2% of the approximately 8% increase in this year’s tax rate.
• If the total to be raised by taxes this year were exactly the same as last year, the total tax bills mailed this year would be exactly the same as last year. Even though the re-val itself drove the tax rate 6.2% higher this year, neither the change in the tax base nor the change in the tax rate have any effect on the total to be raised by taxes. That’s determined strictly by the budget, offsetting revenues, exemptions, and the like.
• The re-val doesn’t impact the total of all the tax bills, but it does shift the tax burden from one property to another. If your property’s valuation went down by more than 6.2%, your 2014 tax bill will be for a smaller percentage of the total tax burden than your 2013 tax bill was. If your property’s valuation did not decrease by at least 6.2%, you’re paying in 2014 a larger portion of the total tax burden than you did in 2013. If your property’s valuation went down by exactly 6.2%, then you’re paying exactly the same portion of the total tax burden as you were before the re-val
• So the difference in your tax bill this year comes from A) the 1.8% increase in the amount to be raised by taxes (the total 2014 tax burden) and B) how much more than (or less than) 6.2% your property’s assessment changed due to the re-val (the shift in how much of the tax burden your property must shoulder).

Bottom line: the tax rate and the total town valuation are pretty much just math that go into calculating the tax bills; they don’t really impact your individual tax bill.

The two things that directly and substantially impact your tax bill are:

A) the total tax burden, also known as the amount to be raised by taxes (which is significantly impacted by the budgets we vote on at Town Meeting and School District Meeting), and

B) the assessed value of your property relative to the total assessed value of all Andover properties (because that determines the portion of the total tax burden that you have to shoulder).