No municipal officers may purchase, erect, substantially enlarge, improve, or extend an existing plant, or lease from others any plant, system, or line provided for in section 40-33-01, unless the proposition has been submitted by a resolution of the governing body to the qualified electors of the city at a biennial or special election called, held, and conducted upon the notice and in the manner specified by this title for the election of the governing body of the city, and has been approved by a majority of the electors voting thereon. If the cost of any enlargement, improvement, or extension will be paid out of the earnings of the plant and the cost does not exceed the sum of five thousand dollars, or if eighty percent or more of the cost of any waterworks, mains, water system, and equipment or appliances therefor is to be paid by special assessments or by the earnings of the plant or by both, the governing body is not required to submit the proposition to the electors of the city. If the improvement and facilities are to provide for a greater and more adequate water supply to meet the needs of the city for domestic use, fire protection, or for sanitation and sewage disposal, regardless of cost the governing body thereof may by resolution provide for the needed improvement and facilities in cooperation with the state or federal government, or any agency thereof, without an election if funds for such cooperation or for defraying the entire cost thereof are available in the municipal utilities fund as defined by section 40-33-10. If the lease by the city of any plant, system, or line provided for in     subsection 5 of section 40-33-01 is from the state, or any agency or institution of the state, the governing body is not required to submit the proposition to the electors of the city.