Mont. Code § 85-2-212
"WATER RIGHTS ORDER
FAILURE TO FILE A CLAIM AS REQUIRED BY LAW WILL RESULT IN A CONCLUSIVE PRESUMPTION THAT THE WATER RIGHT OR CLAIMED WATER RIGHT HAS BEEN ABANDONED. (This introductory sentence shall be printed in not less than 12-point boldface type.) This order is notice of commencement of procedures for the general adjudication of existing rights to the use of water and of the requirement to file a claim for certain existing rights to the use of water. Every person, including but not limited to an individual, partnership, association, public or private corporation, city or other municipality, county, state agency or the state of Montana, and federal agency of the United States of America on its own behalf or as trustee for any Indian or Indian tribe, asserting a claim to an existing right to the use of water arising prior to July 1, 1973, is ordered to file a statement of claim to that right with the department no later than June 30, 1983. Claims for stock and individual as opposed to municipal domestic uses based upon instream flow or ground water sources are exempt from this requirement; however, claims for such uses may be voluntarily filed. Claims filed with the department in the Powder River basin in a declaration filed pursuant to the order of the department of natural resources and conservation or a district court issued pursuant to sections 8 and 9 of Chapter 452, Laws of 1973, or under sections 3 and 4 of Chapter 485, Laws of 1975, are also exempt.
For further information, contact the department of natural resources and conservation, Helena, Montana, for a copy of the law and an explanation of it."
§ 85-2-212, MCA