Mont. Code Ann. § 85-2-510

The regulation of the production, use, or disposal of fresh, brackish, or saline water that is entirely the result of the production of oil or gas, or both, must be under the jurisdiction of the board of oil and gas conservation and is subject to the requirements of 82-11-123. Hearings pertaining to the production, use, or disposal of water from those wells must be held by that board in accordance with the procedures established by that board. The department may petition the board of oil and gas conservation for hearings in regard to those operations, and it must be notified by the board of oil and gas conservation of those hearings instigated by other parties.