Before any sale, conveyance, lease, or operating contract is made of any plant or equipment of any public utility owned by the municipality, there is filed with the municipal finance officer a petition signed by at least fifteen percent of the registered voters of the municipality, based upon the total number of registered voters at the last preceding general election, requesting that the proposition be submitted to the voters at a regular or special election, which petition shall be filed at least ten days preceding the date set for such regular or special election.
SDCL 9-39-37