Mont. Code Ann. § 85-2-236

When a final decree is entered, the water judge shall send a copy to the department. Except as provided in 85-2-306, the department shall on the basis of the final decree issue a certificate of water right to each person decreed an existing right. The original of the certificate shall be sent to the person to whom the right is decreed. The department shall keep a copy of the certificate in its office in Helena.