N.J. Stat. § 58:14-34.24
The State of New Jersey does hereby pledge to and covenant and agree with the holders of any bonds that the State will not limit or alter the rights hereby vested in the commissioners to acquire, construct, maintain, reconstruct and operate the sewerage system and to fulfill the terms of any agreement made with the holders of such bonds or other obligations, and will not in any way impair the rights or remedies of such holders, and will not modify in any way the exemptions from taxation provided for in this act, until the bonds, together with interest thereon, with interest on any unpaid installments of interest, and all costs and expenses in connection with any action or proceeding by or on behalf of such holders, are fully met and discharged; provided that such pledge to and covenant and agreement with the holders of any bonds issued on or after January 1, 1971 does not prohibit authorization hereafter for the commissioners, notwithstanding any other provision of this act or of the original act or acts amendatory thereof or supplemental thereto, to apportion the cost and expense of maintenance, repair and operation of the sewerage system (as in section 11 hereof referred to and described) among the contracting municipalities and other users thereof, upon any basis or bases in addition to or other than the proportion of the amount of sewage by them delivered and discharged into the sewerage system.
N.J.S. § 58:14-34.24