Property Tax returns are filed between January 1 and April 1. The purpose of the tax return is to declare what you own and the value you feel the property is worth. This gives you the opportunity to receive an Assessment Notice, starting the appeal process with the Board of Assessors. Assessment notices will be mailed in the spring from the Tax Assessors, and you will have 45 days to file your appeal with the Board of Assessors. You do not have to file a return each year.