1. The county commission, after receiving the recommendations of the sewer engineer, may, by resolution, establish the boundaries of the sewer district or districts including therein only such lots, tracts and parcels of ground which may be conveniently served by a sewer, except that whenever the commission of a county of the first classification without a charter form of government deems that a countywide wastewater treatment authority would best serve the needs of such county, the commission may establish a countywide sewer district which shall be subject to the provisions of sections 249.430 to 249.660. The action of the county commission in determining the boundaries of said sewer districts shall be conclusive, provided that, except as otherwise provided in this section, no ground shall be included in a sewer district not contained in the natural drainage area or watercourse, or may be conveniently served through said sewer.

2. For each countywide wastewater treatment authority established pursuant to this section, the county commission of such county shall, by resolution, order, or ordinance, appoint five trustees, all of whom shall reside within the county. In the event there is more than one district within the county organized pursuant to this chapter, no less number of the trustees so appointed shall reside within the district having the greatest number of customers than reside in any other such district in the county. The trustees, whose terms shall begin on the date the authority is established, shall be responsible for the control and operation of the countywide wastewater treatment authority and shall have the same powers and duties as the county commission as provided in this chapter. The term of each trustee shall be five years, except that, of the first board appointed, one member shall serve for one year, one member shall serve for two years, one member shall serve for three years, one member shall serve for four years, and one member shall serve for five years. All vacancies after the initial appointment shall be filled by the county commission. The trustees shall be reimbursed by the district for all reasonable expenses incurred in the performance of their duties, which amount shall not exceed the sum of twenty-five dollars per month.