Upon obtaining the approval of the county treasurer, the board of commissioners of a district with more than twenty-five hundred water customers or sewer customers may designate by resolution some other person having experience in financial or fiscal matters as the treasurer of the district. Such a treasurer shall possess all of the powers, responsibilities, and duties of, and shall be subject to the same restrictions as provided by law for, the county treasurer with regard to a district, and the county auditor with regard to district financial matters. Such treasurer shall be bonded for not less than twenty-five thousand dollars. Approval by the county treasurer authorizing such a district to designate its treasurer shall not be arbitrarily or capriciously withheld.