N.J. Stat. § 40A:21-13
The assessor shall determine, on October 1 of the year following the date of the completion of an improvement, conversion or construction, the true taxable value thereof. Except for projects subject to tax agreement, pursuant to sections 9 through 12 of P.L. 1991, c.441, the amount of tax to be paid for the tax year in which the project is completed shall be based on the assessed valuation of the property for the current tax year, minus the amount of the abatement, if any, allowed pursuant to this act and pro rated, plus any portion of the assessed valuation of the improvement, conversion or construction not allowed an exemption pursuant to this act, also pro rated. Subject to the provisions of the adopting ordinance, the property shall continue to be treated in the appropriate manner for each of the four tax years subsequent to the original determination by the assessor and shall be pro rated for the final tax year in which the exemption or abatement expires.
N.J.S. § 40A:21-13