Idaho Code § 42-229
The right to the use of ground water of this state may be acquired only by appropriation. Such appropriation may be perfected by means of the application permit and license procedure as provided in this act; provided, however, that in the event an appropriation has been commenced by diversion and application to beneficial use prior to the effective date of this act it may be perfected under such method of appropriation. All proceedings commenced prior to the effective date of this act for the acquisition of rights to the use of ground water under the provisions of sections 42-201-42-225, Idaho Code, may be completed under the provisions of said sections and rights to the use of ground water may be thereby acquired. But the administration of all rights to the use of ground water, whenever or however acquired or to be acquired, shall, unless specifically excepted herefrom, be governed by the provisions of this act.
Idaho Code § 42-229