Idaho Code § 42-2502
The transfer of a water right, in whole or in part, made by such person to other lands so owned by him shall be evidenced by a written instrument executed and acknowledged by such person as other conveyances of real estate, reciting therein the facts, stating the amount of the right transferred and describing the land from which and the land to which the transfer is to be made, and the transfer of a water right or any portion thereof from one person to another shall be evidenced by a written instrument containing similar recitals and executed and acknowledged in like manner by the grantor or lessor.
All of such instruments shall be recorded in the office of the county recorder of the county or counties where the land is situated from which such right is transferred and also in the office of the county recorder of the county or counties where the land is situated to which such right is transferred, and to all of such instruments the recording acts of the state shall apply.
Idaho Code § 42-2502