N.J. Stat. Ann. § 40A:65-23

23. The joint contract shall be terminated upon the adoption of a resolution to that effect by the governing bodies of two-thirds of the local units then participating; except that if only two local units are then participating, adoption of a resolution by both units shall be required to terminate the contract. The termination shall not be made effective earlier than the end of the fiscal year next succeeding the fiscal year in which the last of the required number of local units adopts its termination resolution