Water Adjudication
(Pre-1973 Water Rights)

Prior to 1973, a person could gain a water right simply by putting water to beneficial use. As a result, it was unknown how many water rights existed or how much water had been claimed by users. The Montana Water Use Act of 1973 provided a formal process both for establishing a new water right and for documenting all the existing claims. The Water Use Act established a permit system for new uses of water. Learn more about the permitting process on the Applying for Water Rights page. It also created the statewide adjudication process, which began in 1979, setting forth the amounts, ownership and priority dates for existing water rights.

Although statewide adjudication is primarily a judicial process, the DNRC has played a vital supporting role. From 1979 to 2025, DNRC staff followed Montana Supreme Court rules to systematically examine every timely filed historical water right claim. This “claims examination” process ensured that each claim was accurate, standardized, and consistent with the criteria for a historical water right. DNRC also worked with claimants to resolve potential issues before submitting examined claims to the Water Court for decree. Claims examination was completed for all basins in 2025 .

DNRC continues to provide technical assistance to the public and Water Court throughout the decree process. Please reach out to your water resources regional office if you need assistance with understanding this process or need help finding and understanding your water rights.

Check out the interactive mapping tool, WaterMapper. Discover the history, science, and parameters surrounding Montana water rights and how your water right fits within that story.

WaterMapper