Idaho Code § 43-2304
The resolution authorizing the issuance of any bonds or interim notes hereunder or any resolution authorizing the execution of any contract hereunder may be published one time in a newspaper of general circulation in the district. For a period of thirty (30) days from the date of such publication, any person in interest may file suit in any court of competent jurisdiction to contest the regularity, formality or legality of the proceedings authorizing the bonds, the interim notes, the execution of such contract or the legality of such resolution and its provisions or of the contract or of the bonds or interim notes to be issued pursuant thereto and the provisions securing the bonds or interim notes. After the expiration of such thirty (30) day period no one shall have any right of action to contest the validity of the contract or of the bonds or interim notes or of such proceedings or of such resolution or the validity of the pledges and covenants made in such proceedings and resolution and the contract and the bonds and interim notes and the provisions for their payment shall be conclusively presumed to be legal and no court shall thereafter have authority to inquire into such matters.
Idaho Code § 43-2304