N.J. Stat. § 58:14-12
Any two or more of said municipalities, at any time after the expiration of three months from the date of the delivery of copies of the maps, plans, specifications and estimates as aforesaid, may, by resolution of their governing bodies or boards having charge of their finances, enter into a contract in writing with each other and with the commissioners, in their corporate capacities, for the construction, maintenance and operation of said sewer, plant and works, with the appurtenances, or of so much thereof as may be necessary and appropriate for the contracting municipalities, together with works, machinery, appliances and other things requisite or useful for the purposes to be accomplished by the intercepting sewer, and for the purchase of lands, rights in lands and other property requisite or useful therefor. The contract herein authorized shall generally describe the route, line, size and capacity of such intercepting sewer and shall fix the percentage of the capacity therein, to the use of which each of the contracting municipalities shall be entitled, together with the percentage of the cost and expense of construction, repair, maintenance and operation of the same to be paid by each of the contracting municipalities.
N.J.S. § 58:14-12