N.J. Stat. Ann. § 18A:8-3.2

When the board of education of a school district situated in any municipality pays any portion of an indebtedness which existed at the time of the formation of a new municipality or part thereof, or at the time of the annexation of such municipality to another and which was assumed by and became the obligation of the board of education of the school district situated in the new municipality, the amount of such payment with interest shall be repaid by the last mentioned board.