N.J. Stat. § 58:14-16
The contract shall provide for the construction by the commissioners of an intercepting sewer or sewers, plant and works, reasonably sufficient in size and capacity to intercept and dispose of sewage and other polluting matter of the contracting municipalities for the present, and, so far as can be estimated and foreseen, for the future, and the sewer or sewers, plant and works may differ substantially in details from the preliminary maps, plans, specifications and estimates submitted to the municipalities as hereinbefore directed. The several contracting municipalities and the commissioners are hereby vested with absolute discretion in the determination of the size and capacity of each such intercepting sewer, plant and works. The contract shall also provide for the building, repair, operation, maintenance and cleaning of any such intercepting sewer, plant and works, and for the purchase of the necessary lands, rights in land and other property by the commissioners, and for the payment of the cost and expense thereof by the several contracting municipalities to the commissioners.
N.J.S. § 58:14-16