New Jersey Statutes Title 32. Interstate and Port Authorities and Commissions 32 § 20-35

(a) The entire cost of such construction and maintenance shall be borne by the Commonwealth of Pennsylvania or by said commission or public body or municipality, but the State of New Jersey shall be entitled to become a participant in the said project and acquire a proportionate interest therein, not to exceed a thirty per centum (30%) interest, by paying to the Commonwealth of Pennsylvania or to said commission or public body or municipality, immediately upon the completion of the project, such proportionate amount of the cost of the project, and thereafter from time to time the proportionate cost of maintaining the project.

(b) The county of Sussex in the State of New Jersey shall have the right to divert from the Wallpack Bend reservoir for the water supply of its municipalities a quantity of water not exceeding 25 million gallons daily and shall pay for the quantities diverted the average production cost thereof calculated by sound accounting principles.Provided, that if the State of New Jersey shall have participated in the construction of the project, any water diverted by the county of Sussex shall be taken out of New Jersey's proportionate share of the water, and the county of Sussex shall make its payments therefor solely to the State of New Jersey.