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Montana: Laws & Legal Considerations

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Rainwater harvesting: unrestricted

Montana places no permit requirement on residential rainwater harvesting for typical household use.

RuleMontana
Source water Rooftop or other catchment
Permit required No, for typical residential collection
Permitted uses Non-potable, typically irrigation and similar uses

Where to find it: the Montana Department of Natural Resources and Conservation (dnrc.mt.gov) administers water rights generally.

Water rights: prior appropriation, written directly into the state constitution

Montana follows prior appropriation, the same “first in time, first in right” doctrine as Utah, Oregon, Washington, Arizona, Kansas, and New Mexico, with two features worth calling out specifically.

ConceptHow it works in Montana
Basic rule The earliest-dated appropriator holds first claim during a shortage; owning land along water doesn't itself grant a right to use it
'Use it or lose it' A water right must be actively put to beneficial use to remain valid, a specific enforcement mechanism named explicitly in Montana law
Constitutional guarantee Montana's water rights framework is written directly into Article IX, Section 3 of the state constitution, not left to statute alone

Where to find it: the Montana Department of Natural Resources and Conservation administers appropriation permits and the statewide water-right recording system.

Permitless carry since 2021

Montana has recognized full constitutional carry since House Bill 102 took effect February 18, 2021.

RequirementDetail
Standard Permitless carry, concealed, for any resident or visitor 18+ legally eligible to possess a firearm, in most locations
Applies to visitors too Non-residents passing through Montana are covered by the same permitless standard as residents
Still applies Prohibited-location rules, federal law overlays (e.g., federal buildings, national parks' specific restrictions), and reciprocity considerations when traveling elsewhere

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