What can I do about my assessment?

The assessor is governed by the state. A suggestion would be to search for properties that have recently sold (in this area) that are similar to your home. You can go to the town hall and look up any assessment on any home for comparison. Talk to the assessor and if not satisfied, sign up for the grievance process. It is up to you so be prepared with facts and figures. No one will look out for your interests but you. Look at ZILLOW.com to find recent sales and comparisons.