§49-10 Rates, rentals, fees and charges; undertakings and loan programs to be self-sustaining. The governing body issuing revenue bonds pursuant to this chapter shall impose, prescribe and collect, or authorize and require the imposition, prescription and collection of, rates, rentals, fees or charges for the use and services of, and the facilities and commodities furnished by, the undertaking or for the use and services and benefits of the loan program for which the revenue bonds are issued, and shall revise, or require revision of, the rates, rentals, fees or charges from time to time whenever necessary, so that, together with the proceeds of the user taxes derived with respect to the undertaking pledged to the payment of the revenue bonds, the undertaking or loan program shall be and always remain self-sustaining. The rates, rentals, fees or charges imposed and prescribed shall produce revenue which, together with the proceeds of such user taxes, will be at least sufficient: