N.J. Stat. § 58:14-34.21
Neither the commissioners nor any municipality shall have power to mortgage, pledge, encumber or otherwise dispose of any part of the sewerage system, except that the commissioners may dispose of such part or parts thereof as may be no longer necessary for the purposes of the commissioners. The provisions of this section shall be deemed to constitute a part of the contract with the holder of any bonds. All property of the commissioners shall be exempt from levy and sale by virtue of an execution and no execution or other judicial process shall issue against the same nor shall any judgment against the commissioners be a charge or lien upon its property; provided, however, that nothing herein contained shall apply to or limit the rights of the holder of any bonds to pursue any remedy for the enforcement of any pledge or lien given by the commissioners on its system revenues or other moneys.
N.J.S. § 58:14-34.21