Idaho Code § 43-402
The bonds authorized by any vote shall be designated as a series and the series shall be numbered consecutively as authorized. The portion of the bonds of a series sold at any time shall be designated as an issue, and each issue shall be numbered in its order. The bonds of each issue shall be numbered consecutively, commencing with those earliest falling due. All bonds shall be negotiable in form and payable in money of the United States.
Interest coupons shall be attached thereto, and all bonds and coupons shall be dated on January 1, or July 1 next following the date of their authorization and they shall bear interest, payable semiannually on the first days of January and July of each year. The principal and interest shall be payable at the place designated therein. Said bonds shall be each of the denomination of not less than $100 nor more than $5000, and shall be signed by the president and secretary, and the seal of the board of directors shall be affixed thereto. Coupons attached to each bond shall be signed by the secretary. Said bonds shall express on their face that they were issued by the authority of this title, naming it, and shall also state the number of the issue of which such bonds are a part. The secretary and treasurer shall each keep a record of the bonds sold, their number, the date of sale, the price received, and the name of the purchaser. In case the money raised by the sale of all the bonds be insufficient for the completion of the plans and works adopted, and additional bonds be not voted, it shall be the duty of the board of directors to provide for the completion of said plan by a levy of assessment therefor, in the manner hereinafter provided.
Bonds may be issued with maturities under any one (1) of the following plans:
Plan No. 1, Eleven-Twenty (11-20) Year Bonds. At the expiration of eleven (11) years from each issue, five per cent (5%) of the whole number of bonds of such issue; at the expiration of twelve (12) years, six per cent (6%); at the expiration of thirteen (13) years, seven per cent (7%); at the expiration of fourteen (14) years, eight per cent (8%); at the expiration of fifteen (15) years, nine per cent (9%); at the expiration of sixteen (16) years, ten per cent (10%); at the expiration of seventeen (17) years, eleven per cent (11%); at the expiration of eighteen (18) years, thirteen per cent (13%); at the expiration of nineteen (19) years, fifteen per cent (15%); at the expiration of twenty (20) years, sixteen per cent (16%); provided, that such percentages may be changed sufficiently so that every bond shall be in an amount of $100 or a multiple thereof, and the above provisions shall not be construed to require any single bond to fall due in partial payments.
Plan No. 2, Amortization Plan. Bonds may be issued on the amortization plan covering a period of forty (40) years or less, at the discretion of the board of directors, with the principal payable in annual or semiannual instalments, so arranged as to maturities that the combined principal and interest payments during the entire period shall be approximately the same each year during the life of the issue.
Plan No. 3, Five-Thirty (5-30) Year Bonds. Bonds may be issued payable in annual instalments over a period of thirty (30) years or less. The board of directors may fix a date, not more than five (5) years from the date of each issue, for the earliest maturity of each issue. Beginning with the date of the earliest maturity of each issue, the principal shall be payable in annual amounts designated by the board of directors over the remaining life of the bonds not to exceed thirty (30) years from the date of issue.
Idaho Code § 43-402