Wyo. Stat. § 15-6-103
The governing body of any city or town, when considered expedient, may order any improvement or improvements, and determine its character, kind and extent. If the improvement is to be paving, it shall designate the kinds of pavement to be used. It shall provide for the maintenance of an improvement for a specified period not to exceed five (5) years and include the cost of that maintenance in the assessment for making the improvements. It shall levy and collect an assessment upon all lots, parts of lots and parcels of land specially benefited by the improvement to defray all or any part of the cost and expense and determine what lots, parts of lots and parcels of land are specially benefited by the improvements and the amount each is benefited.
W.S. 15-6-103