Neb. Rev. Stat. § 23-104.01: Neb. Rev. Stat. § 23-104.01

Any agreement between counties for the joint exercise of powers shall:

(1)(a) Be in writing and signed by a majority of the board of supervisors or county commissioners of each county that is a party to the agreement; and

(b) After being signed pursuant to subdivision (1)(a) of this section, be filed and recorded in the office of the county clerk of each county that is a party to the agreement;

(2) Specify the powers and obligations of each party under the agreement. Such powers shall:

(a) Be limited to powers imposed by law upon a county that is a party to the agreement or its board of supervisors or county commissioners; and

(b) Not include powers specifically conferred upon and required to be carried out by other elected officers of a county that is a party to the agreement;

(3) Specify the allocation and payment of expenses to be paid by each county under the agreement;

(4) Provide for the following to be reserved to and remain a function of the board of supervisors or county commissioners of each county that is a party to the agreement:

(a) Final action upon the allowance and payment of any claims and obligations against each county; and

(b) The levy and collection of taxes to pay claims and obligations under the agreement; and

(5) Be subject to the Interlocal Cooperation Act.