NH RSA 76:16 Abatement applications can be filed each year after receipt of the fall tax bill.  Applications must be received or postmarked by March 1 of the year following (2021 applications are due by 3/1/2022).  Click the following link for more information and the abatement application:  https://www.btla.nh.gov/jurisdiction/property-tax

Please see RSA 76:16 for more information:  http://www.gencourt.state.nh.us/rsa/html/v/76/76-16.htm