Iowa Code § 455B.272: Termination of permit.

The right of the permittee and the permittee’s successors to the use of water shall terminate when the permittee or the permittee’s successors fail for three consecutive years to use it for the specific beneficial purpose authorized in the permit and, after notification by the department of intent to cancel the permit for nonuse, the permittee or the permittee’s successors fail to demonstrate adequate plans to use water within a reasonable time. However, nonuse of water due to adequate rainfall does not constitute grounds for cancellation of a permit to use water for irrigation.