Exempt property
Property that pays no property tax because of who owns it and how it is used, such as public schools, government property, church and charitable property, and cemeteries. Assessors code it as Class 15.
New Jersey example
A town-owned public library is Class 15C, public property. A building owned by a church and used in its work is Class 15D. Religious, charitable and other nonprofit owners file an Initial Statement to claim the exemption and a Further Statement every third year to keep it. Government owners do not file these.
Official source
Handbook for New Jersey Assessors (NJ Division of Taxation, revised July 2024)
This is a plain-English summary. Rules and dollar amounts change, so check the official source or a professional before you file or sign anything.