Whenever there exists no immediate need for the use of the dredge boat, tools and other machinery authorized to be purchased by section 243.330 by districts contributing to the purchase thereof, then it shall be lawful for the county commission to lease or rent the same to any drainage or levee district for the doing of work in such county, upon such terms and conditions as said county commission shall by order of record impose; provided, however, that such county commission shall not lease or rent the same beyond a reasonable time; and provided further, that at least a reasonable rental value of same, or an amount sufficient to take care of all necessary repairs and depreciations caused and occasioned by the doing of the work contemplated, shall be first agreed upon and such amount paid into the general fund created by section 243.330 for the purchase of such dredge boat, tools and other machinery before same shall be so leased or rented.