Wyo. Stat. § 18-12-134: Duty to levy tax for interest and redemption of outstanding bonds.

The commissioners shall annually levy a tax for that year upon the property of the district for the interest and principal falling due on all outstanding bonds of the district. The levy shall be made at the same time as the levy of taxes for county purposes. The tax shall be sufficient to pay the interest on the bonds as it becomes due and to provide a sinking fund for the payment of the principal on or before maturity and may include an allowance for an annual reserve established to adjust for fluctuating tax levies.