Wis. Stat. § 23.20

The department may permit any town, county or state agency to obtain gravel, sand, fill dirt or other fill material needed for road purposes from any department-owned gravel pit or similar facility if this material is unavailable from private vendors within a reasonable distance of the worksite. The department may require environmental safeguards before permitting a town, county or state agency to obtain this material. The department shall charge a fee for this material commensurate with the fee charged by private vendors.