Mont. Code Ann. § 85-2-102

Definitions

Unless the context requires otherwise, in this chapter, the following definitions apply:

(1) "Appropriate" or "appropriation" means:

(a) to divert, impound, or withdraw, including by stock for stock water, a quantity of water for a beneficial use;

(b) in the case of a public agency, to reserve water in accordance with 85-2-316;

(c) in the case of the department of fish, wildlife, and parks, to change an appropriation right to instream flow to protect, maintain, or enhance streamflows to benefit the fishery resource in accordance with 85-2-436;

(d) in the case of the United States department of agriculture, forest service:

(i) instream flows and in situ use of water created in 85-20-1401, Article V; or

(ii) to change an appropriation right to divert or withdraw water under subsection (1)(a) to instream flow to protect, maintain, or enhance streamflows in accordance with 85-2-320;

(e) temporary changes or leases for instream flow to maintain or enhance instream flow to benefit the fishery resource in accordance with 85-2-408;

(f) a use of water for aquifer recharge or mitigation; or

(g) a use of water for an aquifer storage and recovery project as provided in 85-2-368.

(2) "Appropriation right" has the same meaning as "water right" as defined in this section.

(3) "Aquifer recharge" means either the controlled subsurface addition of water directly to the aquifer or controlled application of water to the ground surface for the purpose of replenishing the aquifer to offset adverse effects resulting from net depletion of surface water.

(4) "Aquifer storage and recovery project" means a project involving the use of an aquifer to temporarily store water through various means, including but not limited to injection, surface spreading and infiltration, drain fields, or another department-approved method. The stored water may be either pumped from the injection well or other wells for beneficial use or allowed to naturally drain away for a beneficial use.

(5) "Beneficial use", unless otherwise provided, means:

(a) a use of water for the benefit of the appropriator, other persons, or the public, including but not limited to agricultural, stock water, domestic, fish and wildlife, industrial, irrigation, mining, municipal, power, and recreational uses;

(b) a use of water appropriated by the department for the state water leasing program under 85-2-141 and of water leased under a valid lease issued by the department under 85-2-141;

(c) a use of water by the department of fish, wildlife, and parks through a change in an appropriation right for instream flow to protect, maintain, or enhance streamflows to benefit the fishery resource authorized under 85-2-436;

(d) a use of water through a temporary change in appropriation right or lease to enhance instream flow to benefit the fishery resource in accordance with 85-2-408;

(e) a use of water through a temporary lease of an appropriation right approved by the department pursuant to 85-2-428;

(f) a use of water for aquifer recharge or mitigation; or

(g) a use of water for an aquifer storage and recovery project as provided in 85-2-368.

(6) "Certificate" means a certificate of water right issued by the department.

(7) (a) "Change in appropriation right" means a change in the place of diversion, the place of use, the purpose of use, or the place of storage.

(b) The term does not include a change in water use related to the method of irrigation.

(8) "Commission" means the fish and wildlife commission provided for in 2-15-3402.

(9) "Correct and complete" means that the information required to be submitted conforms to the standard of substantial credible information and that all of the necessary parts of the form requiring the information have been filled in with the required information for the department to begin evaluating the information.

(10) "Declaration" means the declaration of an existing right filed with the department under section 8, Chapter 452, Laws of 1973.

(11) "Department" means the department of natural resources and conservation provided for in Title 2, chapter 15, part 33.

(12) "Developed spring" means any point where ground water emerges naturally, that has subsequently been physically altered, and from which ground water flows under natural pressures or is artificially withdrawn.

(13) "Existing right" or "existing water right" means a right to the use of water that would be protected under the law as it existed prior to July 1, 1973. The term includes federal non-Indian and Indian reserved water rights created under federal law and water rights created under state law.

(14) "Ground water" means any water that is beneath the ground surface.

(15) "Late claim" means a claim to an existing right forfeited pursuant to the conclusive presumption of abandonment under 85-2-226.

(16) "Mitigation" means the reallocation of surface water or ground water through a change in appropriation right or other means that does not result in surface water being introduced into an aquifer through aquifer recharge to offset adverse effects resulting from net depletion of surface water.

(17) "Municipality" means an incorporated city or town organized and incorporated under Title 7, chapter 2.

(18) (a) "National forest system lands" means all lands within Montana that are owned by the United States and administered by the secretary of agriculture through the forest service.

(b) The term does not include any lands within the exterior boundaries of national forest system units that are not owned by the United States and administered by the secretary of agriculture through the forest service.

(19) "Nonconsumptive use" means a beneficial use of water that does not cause a reduction in the source of supply and in which substantially all of the water returns without delay to the source of supply, causing little or no disruption in stream conditions.

(20) "Permit" means the permit to appropriate issued by the department under 85-2-301 through 85-2-303 and 85-2-306 through 85-2-314.

(21) "Person" means an individual, association, partnership, corporation, state agency, political subdivision, the United States or any agency of the United States, or any other entity.

(22) (a) "Political subdivision" means any county, incorporated city or town, public corporation, or district created pursuant to state law or other public body of the state empowered to appropriate water.

(b) The term does not mean a private corporation, association, or group.

(23) "Salvage" means to make water available for beneficial use from an existing valid appropriation through application of water-saving methods.

(24) "State water reservation" means a water right created under state law after July 1, 1973, that reserves water for existing or future beneficial uses or that maintains a minimum flow, level, or quality of water throughout the year or at periods or for defined lengths of time.

(25) "Stream depletion zone" means an area where hydrogeologic modeling concludes that as a result of a ground water withdrawal, the surface water would be depleted by a rate equal to at least 30% of the ground water withdrawn within 30 days after the first day a well or developed spring is pumped at a rate of 35 gallons a minute.

(26) "Substantial credible information" means probable, believable facts sufficient to support a reasonable legal theory upon which the department should proceed with the action requested by the person providing the information.

(27) "Waste" means the unreasonable loss of water through the design or negligent operation of an appropriation or water distribution facility or the application of water to anything but a beneficial use.

(28) "Water" means all water of the state, surface and subsurface, regardless of its character or manner of occurrence, including but not limited to geothermal water, diffuse surface water, and sewage effluent.

(29) "Water division" means a drainage basin as defined in 3-7-102.

(30) "Water judge" means a judge as provided for in Title 3, chapter 7.

(31) "Water master" means a master as provided for in Title 3, chapter 7.

(32) (a) "Water right" means the right to appropriate water pursuant to an existing right, a permit, a certificate of water right, a state water reservation, or a compact.

(b) The term does not include an authorized notice of intent to appropriate groundwater pursuant to 85-2-306.

(33) "Watercourse" means any naturally occurring stream or river from which water is diverted for beneficial uses. It does not include ditches, culverts, or other constructed waterways.

(34) "Well" means any artificial opening or excavation in the ground, however made, by which ground water is sought or can be obtained or through which it flows under natural pressures or is artificially withdrawn.

Opinions construing this section

22 opinions
2026 MT 34 Feb 24, 2026 Affirmed in part, reversed in part
Petrich Fam. & Melin v. T.U
Majority by Beth Baker · 5 to 0
Const. art. IX, § 3(4). Decreed rights, use rights, and filed appropriation rights are types of historical rights deemed existing water rights under the WUA. Section 85-2-102(13), MCA (“‘Existing right’ or ‘Existing water right’ means a right to the use of water that would be protected under the law as it existed prior to July 1, 1
2025 MT 1 Jan 2, 2025 Affirmed
Trout Unlimited v. DNRC
Majority by Jim Rice · 5 to 2 with 1 concurring
301(1), MCA. To “appropriate” water is “to divert, impound, or withdraw, including by stock for stock water, a quantity of water for a beneficial use.” Section 85-2-102(1)(a), MCA. In turn, “beneficial use” is defined as “a use of water for the benefit of the appropriator, other persons, or the public, including but not limited to
2025 MT 1 Jan 2, 2025 Affirmed
Trout Unlimited v. DNRC
Dissenting by Laurie McKinnon · 5 to 2 with 1 concurring
er only for a beneficial use” and “the application of water to anything but a beneficial use” is prohibited as unlawful “waste.” Sections 85-2-301(1), 85-2-102(27), MCA. The structure of the MWUA thus deems applications for water are either for beneficial use or impermissible waste. The MWUA was designed to provide for compreh
2024 MT 210 Sep 17, 2024 Reversed
Town of Kevin v. MT DNR&C
Majority by Mike McGrath · 5 to 0
s Ranch Corp., 2016 MT 348, ¶¶ 12, 34, 386 Mont. 121, 386 P.3d 952. Under the Montana Water Use Act (MWUA), a municipal use is one such “beneficial use.” Section 85-2-102(5)(a), MCA. ¶15 Municipalities are required to follow the same permitting and change of use processes under the MWUA as individual rights-holders. Section 85-2-302(1),
2024 MT 158 Jul 30, 2024 Affirmed
Bradley Livestock v. Fraser
Majority by Mike McGrath · 5 to 0
While the MWUA recognized “existing rights” as rights “to the use of water that would be protected under the law as it existed prior to July 1, 1973,” § 85-2-102(13), MCA, it required individuals claiming pre-1973 water rights to file them with the Department of Natural Resources and Conservation by April 30, 1982, “or be conc
Official Annotations archive.org, 2025 edition
History:
En. Sec. 3, Ch. 452, L. 1973
Amd. Sec. 1, Ch. 192, L. 1974
Amd. Sec. 1, Ch. 485, L. 1975
Amd. Sec. 1, Ch. 416, L. 1977
Amd. Sec. 7, Ch. 460, L. 1977
R.C.M. 1947, 89-867
Amd. Sec. 1, Ch. 327, L. 1979
Amd. Sec. 1, Ch. 552, L. 1979
Amd. Sec. 29, Ch. 697, L. 1979
Amd. Sec. 1, Ch. 573, L. 1985
Amd. Sec. 1, Ch. 658, L. 1989
Amd. Sec. 2, Ch. 28, L. 1991
Amd. Sec. 2, Ch. 308, L. 1991
Amd. Sec. 1, Ch. 543, L. 1991
Amd. Sec. 1, Ch. 805, L. 1991
Amd. Sec. 1, Ch. 370, L. 1993
Amd. Sec. 1, Ch. 629, L. 1993
Amd. Sec. 440, Ch. 418, L. 1995
Amd. Sec. 4, Ch. 487, L. 1995
Amd. Sec. 2, Ch. 497, L. 1997
Amd. Sec. 1, Ch. 78, L. 2001 (HB 114 - Story, Bob (R) HD 24)
Amd. Sec. 3, Ch. 70, L. 2005 (HB 178 - Taylor, Janna (R) HD 11)
Amd. Sec. 1, Ch. 85, L. 2005
Amd. Sec. 3, Ch. 213, L. 2007 (SB 248 - Story, Bob (R) SD 30)
Amd. Sec. 1, Ch. 391, L. 2007 (HB 831 - McNutt, Walter (R) HD 37)
Amd. Sec. 1, Ch. 448, L. 2007
Amd. Sec. 1, Ch. 251, L. 2009
Amd. Sec. 2, Ch. 29, L. 2011
Amd. Sec. 23, Ch. 235, L. 2013 (HB 24 - Ankney, Duane (R) HD 43)
Amd. Sec. 1, Ch. 335, L. 2013 (HB 106 - Connell, Pat (R) HD 87)
Amd. Sec. 1, Ch. 409, L. 2013
Amd. Sec. 1, Ch. 421, L. 2013
Amd. Sec. 1, Ch. 69, L. 2017
Amd. Sec. 1, Ch. 59, L. 2019
Amd. Sec. 2, Ch. 347, L. 2025
Amd. Sec. 6, Ch. 708, L. 2025 (HB 681 - Fitzpatrick, John (R) HD 76)