Such bonds of the district shall be authorized by one or more resolutions of the board, shall be payable solely from the income and revenues to be derived from the operation of the facilities of the district, and shall not constitute an indebtedness or pledge of the general credit of the district. The bonds shall be of such series; bear such date or dates; mature at such time or times not exceeding fifty years from their respective dates; bear interest at such rate or rates not exceeding six per cent per annum, payable semiannually; be in such denominations; be in such form, either coupon or fully registered without coupons; carry such registration and exchangeability privileges; be payable in such medium of payment and at such place or places; be subject to such terms of redemption not exceeding one hundred five per cent of the principal amount thereof, and be entitled to such priorities on the aforesaid income and revenues as the resolution or resolutions provide. So long as any of such bonds are outstanding, the board shall impose and collect fees and charges for the water and services furnished by its facilities in such amounts and at such rates as are fully sufficient at all times to (1) pay the expenses of operating and maintaining the facilities; (2) provide a sinking fund sufficient to assure the prompt payment of principal of and interest on the bonds as each falls due; (3) provide such reasonable fund for contingencies as may be required by the resolution authorizing the bonds, and (4) provide an adequate depreciation fund for repairs, extensions, and improvements to the facilities necessary to assure adequate and efficient service to the public.
La. R.S. § 38:3085.4