(a) Any powers, privileges or authority of a public agency of this state relating to public water supplies, or the transportation or treatment of wastewater, may be exercised jointly with any other public agency of this state, or with any agency of the United States to the extent that the laws of the United States permit. Any agency of the state government when acting jointly with any public or private agency may exercise all of the powers, privileges and authority conferred by this act upon a public agency.
(b) Any public agency may enter into agreements with one or more other public agencies for the purpose of organizing a regional water authority, regional wastewater authority, or regional water and wastewater authority. Appropriate action by ordinance, resolution or otherwise pursuant to law of the governing bodies of the participating public agencies shall be necessary before any such agreement may enter into force.
(c) Any such agreement shall specify the following:
(1) Its duration;