Wyo. Stat. § 41-4-506
Whenever the state engineer places his endorsement of approval on any application for a water permit, he shall require that actual construction work be completed within the time set by him in the permit. The time set for completion shall not exceed a period of five (5) years after the date of approval of application. In the case of an application for a ditch permit, he shall further require that the application of the water to beneficial use must be completed before the date which he shall specify, and which shall not be earlier than the date specified for the completion of construction; and that final proof of appropriation must be submitted within five (5) years after the date specified for the completion of the application of the water to beneficial use. He may limit the application to a less period of time for the completion of construction and application of water to beneficial use than is asked for in the application. For good cause shown, the state engineer may at any time, or from time to time, before the date of expiration, extend any or all of these periods. An extension of time for compliance with any of the specified requirements shall be construed to automatically extend for a like period the time for compliance with any of the specific requirements in relation to which the time expires thereafter. Default by the holder of the permit in any of the specified requirements shall work a forfeiture of the water right involved. The state engineer may upon such default cancel the permit. The state engineer shall, at least three (3) months before default in any of these requirements shall be operative, notify the permit holder when the time allowed will expire. Notification may be delivered by United States postal service, by other generally accepted mail delivery method to the post-office address given by the permit holder or by email or other electronic means that provides actual notice to the permit holder. If the permit holder cannot be reached by mail or by email, the state engineer shall notify the permit holder by certified mail to the permit holder's last known address and shall publish notice of the default on the state engineer's official website and for three (3) weeks in a newspaper of general circulation published in the county, or in case there is no newspaper of general circulation published in the county, then in a newspaper published in the state of Wyoming and in general circulation in the county, the last publication to be at least two (2) months before cancellation of the permit.
W.S. 41-4-506