Wyo. Stat. Ann. § 41-9-278

In making their assessments of benefits and for the work to be done under the provisions of this amendment, the commissioners shall regard the proposed work as an integral part of an entire system, and shall take into consideration all assessments of benefits and for construction previously made, in order that, insofar as practicable, no part of the district shall bear an unjust portion of the total cost of the entire system.