N.D. Cent. Code § 61-24.5-03
The southwest water authority shall consist of that part of the state which is included within the boundaries of Dunn, Stark, Golden Valley, Billings, Slope, Bowman, Adams, Grant, Hettinger, Morton, and Mercer Counties.
Such authority is a governmental agency, body politic and corporate with the authority to exercise the powers specified in this chapter, or which may be reasonably implied.
Any county adjoining the authority as herein created, or as hereafter composed, may join such authority upon application of its board of county commissioners and the approval of such application by the board of directors of the authority. The board of directors, as a condition of approval of such application, may require payments as may be equitable to equalize the burden of such county with the obligations paid or assumed by the other counties in the authority.
N.D.C.C. § 61-24.5-03