(1) The bonds shall mature serially within not to exceed 30 years from issue date.
(2) The bonds shall bear such rate of interest as the district board shall determine.
(3) The bonds shall be so conditioned that the health district agrees therein to pay to the bearer, at a place named, the principal sum of the bonds with interest at the rate named, payable semiannually in accordance with the tenor and terms of the interest coupons attached.