Mont. Code Ann. § 7-13-4313

Any person, firm, or corporation residing either inside or outside of the corporate limits of a city owning a municipal water system and/or a municipal sewer system which furnishes water or sewer services as a public utility who shall willfully turn on the waterline or sewerline after the same shall have been shut off by or under the direction of the city for nonpayment of water charges or sewer charges or who shall unlawfully take water from such water system or shall unlawfully make use of such sewer system shall be guilty of a misdemeanor.