Idaho Code § 43-1006

The board of directors, if they deem it not for the best interest of the district to include therein the lands mentioned in the petition, shall order that the petition be rejected. But if they deem it for the best interest of the district, the board may order the lands mentioned in said petition or some part thereof be annexed to said district. The order shall describe the lands to be annexed to said district and the board may cause a survey thereof to be made if deemed necessary, and said order will not become effective until the ninety (90) day period for presentation of an election petition shall have expired without such petition being presented or until approval of the annexation at an election.