Idaho Code § 42-3129
The holder or holders of any title, or evidence of title, representing any body of lands, may file with the board of commissioners of a flood control district a petition in writing praying that said land may be annexed into the district. The lands proposed to be annexed to the district may be contiguous or noncontiguous to the existing boundaries of the district. The petition shall be submitted on a form provided by the district. The petition shall contain a legal description of the lands proposed to be annexed and any other information the district may require, and the petitioners shall state under oath that petitioners hold title to the lands. The board may require petitioners to advance to the district sufficient money to pay the district's estimated costs of proceedings on the petition.
Idaho Code § 42-3129