(a) Where there are contiguous or adjacent districts organized under this chapter or under the suburban improvement district laws or the municipal improvement district laws for either water or sewer services, or both, it shall be permissible for all or any two (2) or more of these districts, whether organized under this chapter, the suburban improvement district laws, the municipal improvement district laws, or any combination thereof, to enter into a contract with each other for the joint operation, maintenance, improvement, enlargement, and betterment of their respective systems or of the consolidated system, to be paid for by charges for the services.
(b) Any such district which has paid its outstanding bonded indebtedness but which has not been turned over to the municipality for operation, may join in contracts for joint operation, and any facilities constructed by any districts outside their boundaries shall be included in the consolidated systems.
(c) These consolidated systems may borrow money to pay and discharge any outstanding bond issues and indebtedness of the districts joining in the consolidations and may borrow money also for improvement, enlargement, and betterment of the facilities of the consolidated systems.
(d) To accomplish these purposes, consolidated systems may issue negotiable bonds or notes evidencing the money so borrowed, to be secured solely by a pledge of the net revenues derived from the operation of the facilities, to bear interest at such rate or rates as prescribed by the boards of the district, and to mature at such time and places as the board shall decide best, and to be issued with such terms of payment, call provisions, and interest rates as the board shall deem to be in the best interest of the inhabitants of the consolidated district.