Water Rights in Montana

Water Rights Defined

Like most western states, Montana governs water resources under the prior appropriation doctrine. Under this doctrine, a water user must have a water right to appropriate water from a stream or groundwater source. For the water right to be valid, it must be used for a beneficial purpose. Each right carries a priority date based on first use. A water user with an older appropriation date is entitled to the use of all of their water right prior to another user with a newer appropriation date stepping in.

Municipal water supply users who buy their water from a water supply system do not need to have a water right, although the municipality or water supply system owner must have a water right to divert water for the system users. On the other hand, private users of water will have to acquire a water right in order to obtain water.

Acquiring Water Rights

In 1973, the Montana Legislature passed the Water Use Act which recognized all then existing water rights and created a permit process for creating new water rights.[i] To obtain a new appropriation of water, an applicant must apply to the Department of Natural Resources Conservation and demonstrate that all applicable statutory criteria are met by a preponderance of evidence.[ii] These criteria include that there is water physically available at the proposed point of diversion in the amount that the applicant seeks to appropriate; and water can reasonably be considered legally available during the period in which the applicant seeks to appropriate, in the amount requested, based on the records of the department and other evidence provided to the department.[iii]

Adjudicating Water Disputes

Disputes regarding existing water rights are handled by a designated water judge within one of the four Water Division Courts in Montana, which divisions are generally found to encompass watersheds.[iv] Otherwise, the State Attorney General may petition for a general water adjudication of all water rights in a particular Water Division, or for a single water basin or subbasin.[v] In adjudication, the Water Court reviews evidence of the historic use of the water right including the point of diversion, amount of water used, and the type of use. The Water Court also oversees any changes in the use because a water right allows the holder of that right to only use water in the prescribed manner.

It is common belief that domestic use of water has an unqualified right of first use over other types of water users, regardless of the priority date. However, Montana does not give priority to one type of user over another.

Competing Water Rights

Under the Prior Appropriation doctrine, the priority of a water right determines when a water user can use water in times of shortage.[vi] Water rights are exercised in accordance with their order of priority, starting with the earliest rights and progressing to the later rights, until the water is all appropriated. When less water is available, senior water right holders are entitled to use their water right prior to junior water right holders. A junior water right user can only use water if it does not adversely affect the senior water right holders use. Even if a junior water rights holder is upstream from a senior water right holder, and the water is insufficient for use by both, the junior must let the water go by for the senior water right holder’s use.

December, 2017

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Note: This post is not legal advice and should not be relied upon as such. Different sets of facts will likely lead to different legal conclusions. If you need assistance with real property matters, contact Macomber Law, PLLC for a forty-five minute no charge consultation.


[i] Title 85, Chapter 2, Mont. Code Ann., commonly referred to as the Montana Water Use Act (effective July 1, 1973); see Mont. Code Ann. § 85-1-101.

[ii] Mont. Code Ann. § 85-2-311(1).

[iii] Mont. Code Ann. § 85-2-311(1)(a).

[iv] Mont. Code Ann. § 3-7-102(1) – (4) (“four water divisions whose boundaries are formed by the natural divides between drainages and the borders of the [S]tate of Montana”); 3-7-201(1) (water judges); see 85-2-406(2) & (3).

[v] Mont. Code Ann. § 85-2-212.

[vi] Mont. Code Ann. § 85-2-401(1) (“As between appropriators, the first in time is the first in right.”)