GENERAL CONTRACT POWERS.

(a) The authority may enter into a contract with a person, including a political subdivision, on terms the board considers desirable, fair, and advantageous for:

(1) the purchase or sale of raw or treated water;

(2) the purchase, lease, use, management, control, or operation of water treatment or distribution facilities or sewer collection and treatment facilities, all or part of the facilities or systems owned by the other political subdivision, in accordance with terms mutually agreed on by the governing bodies of the contracting parties; or

(3) planning, making preliminary surveys, investigations, or feasibility reports, engineering, or reports of any kind.

(b) A contract for the acquisition of an existing water or sewer facility may be made on terms approved by the contracting parties.

(c) If changes in plans or specifications are necessary after performance of a construction contract begins, the board may approve change orders necessary to decrease or increase the amount of materials, equipment, or supplies to be provided under the contract or the amount of work to be performed. The total cost of the change orders may not increase the original contract price by more than 25 percent.