Before and after July 1, 1973
Montana splits its water rights at one date. Before July 1, 1973, a person could gain a right simply by putting water to beneficial use, with no permit and often no paperwork. Some people also filed notices with the county clerk and recorder under an optional system the state first recognized in 1885.
The Montana Water Use Act took effect on July 1, 1973 and created the permit system used today. Any right that began earlier is an "existing right"; anything newer is a new appropriation. Either way, the priority date (the date that sets a right's place in line during a shortage) is what decides who gets water first.
The statewide adjudication
Older rights are being confirmed in a statewide adjudication. Owners documented them on Statements of Claim, filed between 1979 and 1982 or between 2015 and 2019. The Montana Water Court has exclusive jurisdiction over these claims and is working through more than 240,000 state-law rights, along with tribal and federal reserved rights.
DNRC examined every claim for accuracy and finished claims examination in all basins in 2025. The Water Court continues to issue decrees and resolve issues basin by basin.
Some small pre-1973 livestock and domestic uses were exempt from filing a claim. Under House Bill 110 (2017), exempt uses that were not filed as claims by June 30, 2019 no longer carry a prosecutable historic priority date.
Record types in the data
A Statement of Claim is a pre-1973 right going through adjudication. A Permit covers any surface water use begun after July 1, 1973, and groundwater use over 35 gallons per minute (gpm) or 10 acre-feet a year. An acre-foot is the water needed to cover one acre a foot deep, about 326,000 gallons.
A Groundwater Certificate covers a smaller developed well under those limits. You may also see federal and Indian reserved rights, settled through 18 negotiated compacts, and water reservations the state set aside between 1978 and 1994 for future public uses.
Small wells and the 2026 notice requirement
A well or developed spring using 35 gpm or less, and no more than 10 acre-feet a year, does not need a permit. Two or more wells drawing from the same source as one combined appropriation still need a permit once they exceed 10 acre-feet together, regardless of flow rate.
That combined rule now reaches further. In 2024 a district court ruled that every phase of a multi-phase subdivision counts as one combined appropriation.
Since January 1, 2026, anyone planning to use one of these exempt wells must file a Notice of Intent (Form 602I) with DNRC before using the water. Once authorized, the owner has five years to finish the project and file a Notice of Completion of Groundwater Development (Form 602).
When the land is sold
The deed or other recorded conveyance should say plainly what happens to the water right. DNRC then updates its owner records from the Department of Revenue's transfer information or from a Water Right Ownership Update (Form 608) filed by the buyer.
Under MCA 85-2-424, a buyer who receives only part of a right must file the update form. If the property seller and the water right owner on file don't match, DNRC notifies the buyer, who then has 60 days to file. Late filings can draw a penalty.
Use it or lose it
Under MCA 85-2-404, a right is abandoned if the owner stops using it intending to give it up. Ten successive years of nonuse while water was available creates a presumption of abandonment, which the owner can try to rebut. That presumption does not apply to pre-1973 rights until they have been adjudicated.
Checking the official record
DNRC's Water Rights Query System searches existing water rights and Notices of Intent. The WaterMapper tool shows rights on a map. A DNRC regional office can explain a specific claim's history, and a water-rights attorney is the right call before buying property where water matters.