Water Policy Resource Center

The loss of a water right through intentional, prolonged nonuse. Nonuse alone does not necessarily establish abandonment; intent to relinquish the right is generally an important consideration. In adjudication, abandonment may affect whether all or part of a claimed existing right is recognized.

A volume of water equal to the amount needed to cover one acre of land one foot deep. One acre-foot equals approximately 325,851 gallons. It is commonly used to describe annual water use, reservoir storage, groundwater appropriations, and mitigation supplies.

Montana’s statewide judicial process for determining the nature and extent of water rights that existed before July 1, 1973. The Montana Water Court adjudicates these existing rights, resolves objections and issue remarks, incorporates applicable compacts, and issues decrees by basin.

An effect from a proposed appropriation, water-right change, or other water development that interferes with another person’s existing water right. A permit or change applicant generally must show that the proposal will not adversely affect prior appropriators. The analysis can involve timing, quantity, location, consumptive use, return flows, source conditions, and groundwater/surface-water interaction.

The legal acquisition and beneficial use of water. An appropriation may involve diverting surface water, withdrawing groundwater, storing water, or otherwise putting water to a legally recognized beneficial use.

Another term for a water right. It is a legal right to use a specified amount of water from a particular source for a beneficial use, subject to the right’s priority date and other defined elements.

A geologic formation that contains and transmits groundwater in sufficient quantity to supply wells, springs, or other groundwater developments.

The replenishment of water in an aquifer. Recharge may occur naturally or through a managed project.

A project that stores water in an aquifer when water is available and later recovers that water for beneficial use.

A geographic area drained by a stream, river, lake, or other water body and its tributaries; often called a watershed.

A use of water for the benefit of the appropriator, other persons, or the public. Examples include irrigation, stock water, domestic use, municipal use, industrial use, mining, power generation, recreation, fish and wildlife, instream flow, mitigation, aquifer recharge, and aquifer storage and recovery. A water right is generally limited to the amount of water that can be beneficially used.

A request or effort by a senior water-right holder to have junior users reduce or stop use during shortage so the senior right can receive the water to which it is entitled. A formal distribution remedy may require district-court involvement.

A document issued by DNRC that evidences a water right in the state’s centralized records system. Certificates may be issued for completed post-1973 appropriations developed under the applicable process and, after final adjudication, for decreed water rights.

A change application is a request to DNRC for approval to modify certain elements of an existing water right—such as its point of diversion, place of use, purpose of use, or place of storage. The applicant generally must show that the proposed change will not adversely affect other water rights.

DNRC approval required before changing certain elements of an existing water right, such as its point of diversion, place of use, purpose of use, place of storage, or point of discharge. The applicant generally must show that the proposed change will not adversely affect other water rights.

A general reference to a statement of claim filed in the statewide adjudication for an existing water right. A claim is not itself a final court determination; its elements are examined by DNRC and ultimately determined by the Water Court.

DNRC’s review of a statement of claim to determine whether the claim is complete, accurate, and reasonable. The examination process may result in recommendations, modifications, or issue remarks for Water Court resolution.

A basin or subbasin in which new appropriations are restricted or prohibited by statute, administrative rule, compact, or other legal authority. The legal effect of a closure depends on its specific language and any available statutory or regulatory exceptions.

Two or more groundwater developments that draw from the same source and are associated with a single project or development that could have been served by one appropriation. DNRC evaluates whether related wells or developed springs must be treated as a single appropriation rather than separate permit-exception developments.

A public opportunity to submit written comments on DNRC’s draft preliminary determination for a permit or change application.

A legally approved agreement quantifying and resolving certain federal or tribal reserved water rights in Montana. Compacts are subject to required state, tribal, and federal approvals and are incorporated into the statewide adjudication through Water Court proceedings.

The portion of diverted or withdrawn water that is not returned to the source system because it is consumed, evaporated, incorporated into a crop or product, or otherwise unavailable for downstream use. Consumptive use is often important in change, mitigation, and adverse-effect analyses.

An area designated through DNRC rulemaking where groundwater use is subject to special restrictions, additional permitting requirements, or other controls because of groundwater conditions, water-quality concerns, interference, or other statutory criteria.

A flow-rate measurement equal to one cubic foot of water passing a point each second. One cfs equals approximately 448.8 gallons per minute.

The combined effects of multiple water uses or developments over time and across an area. Individually small groundwater uses may collectively affect groundwater levels, springs, connected streams, and water available to other users. This is distinct from the legal combined appropriation criteria.

A Water Court order establishing or addressing water rights in an adjudication basin. Depending on the stage of the proceeding, a decree may be a preliminary decree, temporary preliminary decree, interlocutory decree, reexamination decree, or final decree.

A water right whose elements have been determined by a court decree. In Montana, many pre-July 1, 1973 rights are being established through the statewide Water Court adjudication process.

A spring that has been improved, captured, piped, collected, or otherwise developed for water use.

A water right that authorizes diversion and beneficial use of water as it flows, rather than storage for later use. A direct-flow irrigation right, for example, is generally exercised during a specified period of diversion and use.

The withdrawal, removal, capture, or redirection of water from a natural source. Diversions can occur through a headgate, ditch, pump, well, pipeline, infiltration gallery, reservoir intake, or similar structure.

Physical facilities used to divert, withdraw, store, convey, measure, or control water, including wells, pumps, ditches, headgates, pipelines, reservoirs, and measuring devices.

A historic domestic or livestock water use from an instream or groundwater source that was exempt from the original statement-of-claim filing requirement. This term should not be confused with an exempt well or a post-1973 groundwater permit exception.

Common shorthand for a groundwater development that may qualify for an exception to the ordinary permit process. The phrase can be misleading in two ways. First, a qualifying development is not exempt from all water-right law, filing requirements, local restrictions, combined-appropriation review, or protection of senior water rights. Second, a qualifying groundwater development may divert groundwater via a well, developed spring, or pit/pond. A qualifying development receives a Groundwater Certificate rather than a water use permit. See also Permit exception.

A water right that originated before July 1, 1973. Existing rights are addressed through Montana’s statewide adjudication and may include use rights, filed appropriation rights, decreed rights, federal reserved rights, and tribal reserved rights.

A water right impliedly reserved when the United States sets aside land for a federal purpose and water is necessary to fulfill that purpose. In Montana, many federal reserved rights have been addressed through compact negotiations and Water Court adjudication.

A pre-July 1, 1973 water right documented through Montana’s former county filing system. Filing was historically optional and differs from the post-1973 DNRC permit system.

The Water Court’s final determination of existing water rights within a basin or subbasin after objections, issue remarks, and applicable compact proceedings have been resolved. A final decree provides the basis for future administration of water rights in that basin.

The rate at which water is diverted, withdrawn, or used. It is commonly expressed in gallons per minute, cubic feet per second, miner’s inches, or inches of flow. Flow rate is distinct from volume.

A flow-rate measurement commonly used for wells, pumps, and small pipelines. One cubic foot per second equals approximately 448.8 gallons per minute.

A 17-digit property identifier used by DNRC to associate water rights with land records. A geocode can assist with research, but it does not by itself establish ownership, validity, scope, or enforceability of a water right.

Water beneath the land surface in a saturated geologic formation. Groundwater can be developed through wells, springs, infiltration galleries, or other works. Because groundwater may be hydrologically connected to surface water, pumping can affect streamflow and surface-water rights.

A DNRC-issued certificate for a completed post-June 30, 1973 groundwater development that qualifies under the applicable permit-exception process. It is distinct from a water-use permit.

A well, developed spring, or other project or facility used to obtain and put groundwater to beneficial use. In Montana’s permit-exception and combined-appropriation context, DNRC commonly uses the term when evaluating related wells or developed springs that withdraw from the same source aquifer.

Historical use is the amount, manner, timing, and location of water actually used under a water right in the past. In a change application, historical use helps establish the maximum amount of water that may be changed, including the historical amount diverted and historical consumptive use.

Describes water sources that are linked through the movement of water. For example, a groundwater aquifer may be hydrologically connected to a stream, meaning that groundwater pumping may reduce streamflow or otherwise affect surface-water users.

Water that remains in a stream or water body for a nonconsumptive beneficial use, such as fish and wildlife habitat, water quality, recreation, or other public purposes. Montana law provides specific mechanisms for establishing, leasing, transferring, or protecting instream uses.

A Water Court decree that does not resolve every issue in a basin adjudication. In Montana, interlocutory decrees have been used to address rights not included in an earlier preliminary decree, including certain late-filed or exempt-from-filing claims.

A remark placed on a water-right claim or abstract that identifies a potential factual or legal issue requiring resolution. Issue remarks must be resolved before the Water Court can issue a final decree for the affected basin.

A water right with a later priority date than another right from the same source or hydrologically connected source. During times of shortage, such as drought, junior rights may be curtailed before senior rights.

A temporary arrangement that makes a water right or its use available for an authorized purpose. Montana law provides specific leasing mechanisms, including temporary leases and instream-flow leases.

The amount of water available for a proposed use after accounting for existing legal demands on the source within the area that could be affected. In simple terms, water may be physically present but not legally available if it is already needed to satisfy senior or other existing water rights. Legal availability is evaluated during DNRC’s review of a new water-right permit application. It is one of the statutory criteria an applicant must prove before DNRC may issue a permit for a new appropriation.

The method or structure used to take water from a source, such as a pump, headgate, ditch, well, pipeline, reservoir, or infiltration gallery. It is commonly a defined element of a water right.

A traditional flow-rate measurement. In Montana, one cubic foot per second is approximately 40 miner’s inches.

The reallocation of surface water or groundwater through a change in appropriation right or another lawful mechanism to offset adverse effects caused by the net depletion of surface water.

Depending on the project, mitigation may involve storage, replacement water, releases timed to offset depletions, reduced consumptive use, aquifer recharge, or other legally and technically supportable measures.

The principal body of Montana water-right law, found primarily in Title 85, chapter 2, Montana Code Annotated. Effective July 1, 1973, the Act established the framework for adjudicating existing rights, permitting new appropriations, authorizing changes, maintaining centralized records, and reserving water for certain future uses.

The filing submitted to DNRC (Form 602) after a groundwater development authorized under the applicable permit exception has been completed and put to beneficial use. The owner generally must submit the notice within 60 days after the development is put to use. If the requirements are satisfied, DNRC may issue a groundwater certificate. 

A filing submitted to DNRC (Form 602I) before putting groundwater to use under the applicable permit exception. DNRC reviews whether the proposal qualifies and whether it is part of a combined appropriation. 

A formal challenge to a water-right claim, decree element, compact, permit application, or change application during the applicable legal process. Filing deadlines and eligibility requirements vary by proceeding, so timely review of the relevant notice is essential.

A basin or source area in which existing legal demands on water are sufficiently substantial that new appropriations are restricted, unavailable, or subject to special conditions.

A DNRC administrative filing used to update the ownership information in the state’s water-right records.

The period of the year during which a water right allows water to be diverted from its source. It may differ from the period of use, particularly where water is stored before later use.

The period of the year during which water may be put to the beneficial use identified in a water right. It is distinct from the period of diversion.

A DNRC authorization for a new appropriation of water. Permits are generally required for new surface-water appropriations and for groundwater uses that do not qualify for a statutory permit exception. Basin closures, controlled groundwater areas, compact provisions, and other restrictions may limit or prohibit a proposed appropriation.

A statutory pathway allowing certain limited water developments—most commonly groundwater uses of 35 gallons per minute or less and no more than 10 acre-feet annually—to proceed without a standard permit, subject to DNRC notice and completion filings, combined-appropriation review, and protection of prior water rights. It is often called an “exempt well,” but it is not an exemption from water-right law. See Exempt Well. 

A limited surface-water exception may apply to qualifying livestock pits or reservoirs on nonperennial streams, generally subject to size, annual-volume, parcel-size, filing, and prior-right protection requirements.

Whether water is physically present at the proposed point of diversion or withdrawal in the amount requested. Physical availability is only one part of the permitting inquiry; legal availability and adverse-effect analysis are also required.

The legal location where water is removed from its source. For a surface-water right, this may be a headgate, pump, or intake. For a groundwater right, it is commonly the well location.

The legal location where water is put to beneficial use, such as an irrigated field, subdivision, commercial facility, stockwater location, municipal service area, or industrial site.

The location where water is discharged back to a water source or water body. It may be an element of certain water rights and can be relevant in a change proceeding.

A legally sufficient right to occupy, control, or use the land where water will be put to beneficial use, such as ownership, a lease, easement, or other recognized property interest.

An optional formal process for permit and change applicants. It allows an applicant to receive DNRC technical analyses, or DNRC’s scientific-credibility review of applicant-provided analyses, before filing the application. DNRC identifies earlier issue identification, improved certainty, reduced filing fees, and shorter processing timelines as potential benefits.

A Water Court decree that preliminarily determines existing water rights in a basin or subbasin and opens a formal period for objections. It precedes a final decree.

DNRC’s formal initial decision to grant or deny a permit or change application. Depending on the application process and comments or objections received, the determination may be subject to additional administrative proceedings.

Montana’s foundational water-allocation principle, often summarized as “first in time, first in right.” In a shortage, a water right with an earlier priority date is generally senior to later rights and may receive water before junior rights, subject to the source, decree, compact, court order, and specific circumstances of administration.

The date that establishes a water right’s relative seniority. For an existing use right, it generally reflects the date water was first put to beneficial use. For a new appropriation, it is generally based on DNRC’s receipt of the application. Priority date is central to determining relative rights during shortage administration.

A permit issued before the applicable adjudication, reconciliation, and verification processes are complete. In a basin with a final decree, owners of certain decreed pre-1973 rights may be able to petition DNRC regarding whether a provisional permit should be reduced, modified, or revoked before verification.

Formal notice of a water-right application, decision, decree, or proceeding that gives potentially affected persons an opportunity to review and participate. DNRC uses required public-notice procedures and the Water Right Notification Tool to provide information about pending permit and change applications.

Purpose of use is the authorized beneficial use for which water is used under a water right, such as irrigation, stock water, domestic use, municipal supply, or industrial use. Changing the purpose of use generally requires DNRC approval through a change application.

A Water Court decree resulting from limited reexamination of claims included in earlier temporary preliminary or preliminary decrees.

Statements on a water-right abstract that provide information, clarify or limit the right, identify unique aspects of the claim, or flag factual or legal issues. Issue remarks require final resolution; other remarks may be informational or explanatory.

A well developed to replace an existing well. Montana law and DNRC rules establish conditions under which a replacement well may be treated differently than a new appropriation. The source, location, use, timing, and construction details are important.

A water right reserved under federal law to fulfill the purposes of a tribal or federal reservation, such as an Indian reservation or national forest. In Montana, these rights are commonly quantified through negotiated compacts and incorporated into Water Court decrees.

A structure or impoundment used to store water for later beneficial use. A storage right may identify the source, storage capacity, place of storage, period of storage, purpose, and related use elements.

Water that returns to a stream, aquifer, drainage, or other source after diversion and use. Return flows may be relevant to historic beneficial use, consumptive-use analysis, adverse-effect analysis, mitigation, and change authorization.

Water made available through improvements in water-use efficiency, such as reducing conveyance losses. Whether salvaged water may be used, transferred, leased, or marketed depends on Montana law, the underlying right, historic beneficial use, return flows, and applicable authorization requirements.

A water right with an earlier priority date than another right from the same source or hydrologically connected source. During times of shortage, such as drought, senior rights generally receive water before junior rights.

A water right whose ownership has been separated from the ownership of the land historically associated with it. Ownership documents should expressly address the water right, particularly when land is sold, divided, or transferred.

The water body or aquifer from which a water right draws water, such as a named creek, river, spring, lake, reservoir, or groundwater aquifer.

The aquifer from which a groundwater development withdraws water. Whether multiple wells or springs draw from the same source aquifer can matter in combined-appropriation review.

The sworn document used to assert a pre-July 1, 1973 existing water right in Montana’s statewide adjudication. It identifies the claimed source, quantity, use, diversion, place of use, priority date, and supporting information. It is not, by itself, the final legal determination of the right.

A water right established under Montana law to reserve water for existing or future beneficial uses or to maintain minimum flows, levels, or water quality. Examples include municipal water supply, agricultural irrigation through conservation districts, and instream protection.

A water right authorizing the impoundment of water for later beneficial use. A storage right may work in conjunction with a separate irrigation, municipal, direct-flow, or other water right.

An area established by DNRC rulemaking in a closed basin where groundwater withdrawals are expected to deplete a surface-water source. Groundwater permit-exception appropriations in a designated zone may be subject to more restrictive volume and flow limits.

DNRC’s report to the Water Court summarizing the results of DNRC’s examination of claims in an adjudication basin. The report assists the Water Court in preparing the applicable decree.

Water in streams, rivers, lakes, and other surface water bodies. Surface water may be hydrologically connected to groundwater.

The hydrologic, engineering, water-right, and other analyses required for a permit or change application under DNRC’s process. An applicant may elect to provide the analyses, or DNRC may perform them. If an applicant provides analyses, DNRC performs a scientific-credibility review.

A time-limited authorization to temporarily change an existing water right. Temporary changes are governed by specific statutes and rules and generally require consideration of adverse effect, duration, and the existing elements of the right.

A Water Court decree issued before a preliminary decree when necessary for orderly administration of existing rights. These decrees were often used where federal or tribal reserved-water-right issues remained unresolved.

The statutory DNRC process that follows final adjudication and reconciliation for certain provisional permits and change authorizations. Verification is intended to confirm, modify, reduce, or revoke provisional authorizations as appropriate in light of the final decree and legal availability of water.

The total quantity of water authorized, diverted, stored, or used over a specified period, often stated in acre-feet per year. Volume is distinct from flow rate: flow rate measures how fast water moves, while volume measures how much water is used over time.

A person appointed by a district court to distribute water according to applicable water rights and court authority in a water-distribution project. A commissioner may access points of diversion and regulate flow rates as needed to carry out lawful distribution. DNRC provides data, support, and educational resources.

The administration and apportionment of water among valid water-right holders, often during shortage, in accordance with water-right priorities and court authority. In Montana, distribution generally follows prior appropriation: senior rights are fulfilled before junior rights when supply is insufficient, subject to applicable decrees, compacts, court orders, and other governing law.

A district-court-administered process for distributing water on a particular source when water-user conflicts or shortages make organized administration necessary. At the court’s request, DNRC prepares water-right tabulations, and an appointed commissioner distributes water under the court’s direction.

An attorney with water-law expertise who assists the Montana Water Court. A water master may conduct proceedings, analyze evidence, and prepare reports and recommendations for review by a water judge.

A water right reserved under Montana law for future beneficial uses, such as municipal supply, agricultural development, instream flow, water quality, or fish and wildlife. It differs from a federal or tribal reserved water right.

A legally recognized right to use a specified amount of water from a particular source for a beneficial use, subject to defined elements such as priority date, flow rate or volume, point of diversion, place of use, purpose, and period of use. A water right is a right to use water—not ownership of the water itself.

The state record, found in the DNRC’s Water Rights Query System, summarizing the recognized elements, ownership information, and remarks associated with a water right. Abstracts are commonly reviewed during property due diligence, permitting, adjudication, enforcement, and water-right transactions.

The legal characteristics that define a water right. DNRC identifies the principal elements as source, purpose, point of diversion, place of use, period of use, period of diversion, flow rate, volume, and priority date.

DNRC’s email-alert system for water-right permit and change applications. Users can customize notices by source type, basin, and county to receive information when selected applications reach key milestones. It supplements, but does not replace, legally required public notice.

DNRC’s public records tool for researching Montana water-right information. Searches may use a water-right number, owner name, source, legal land description, property geocode, and other available fields. A result should be reviewed carefully because a property association, abstract, deed, or well log alone may not establish the complete legal status or enforceability of a water right.

The land area that drains rainfall, snowmelt, groundwater discharge, and surface runoff to a common stream, river, lake, or other outlet. See also Basin.

A DNRC authorization to appropriate water for a new use. See also Permit.