The governing body of the county shall advertise for bids for at least thirty days in one or more newspapers published in the county in which the paving district is located for all work to be done and the material to be used in constructing, grading, treating and paving any streets or roadways in the paving district and for equipment to be used in connection therewith, with the right reserved to reject any and all bids, and shall enter into contracts with the lowest responsible bidder therefor and secure competent persons, if deemed advisable, to superintend the work and to counsel and advise in all matters relating thereto.