A thing is deemed to be incidental or appurtenant to land when it is by right used with the land for its benefit, as in the case of a way or watercourse or of a passage for light, air, or heat from or across the land of another.
Incident Or Appurtenance Defined
Mont. Code Ann. § 70-15-105, under Real Property Defined Fixtures and Appurtenances.
Mont. Code Ann. § 70-15-105