LANDLORD GUIDE · MONTANA
Reviewed November 13, 2026
For an existing private residential tenancy. Fixed-term changes, assisted housing, mobile-home spaces and required local forms need a separate review. This guide explains selected rules; it is not a coverage determination or legal advice for a particular property.
Monthly modifications require advance written notice
Montana Code §70-24-311 addresses rules affecting use and occupancy and requires 30 days' written notice when a later rule substantially modifies a monthly tenant's bargain. For a weekly tenancy, the section uses seven days instead. This packet is designed for an existing monthly agreement, not a weekly or fixed-term change.
The rule must be explicit, fair in its application and not adopted to evade the landlord's obligations. Read the agreement's rent and modification provisions alongside the statute; do not treat a notice period as unlimited authority to rewrite a fixed lease.
Describe the change, not just the new number
Identify the new rent, effective date and whether included services remain unchanged. A shift in utility responsibility or a new mandatory charge can substantially change the bargain even when the base-rent line does not move. Use the proper documentation for the full change.
Keep the current agreement and the prior written rules so you can identify exactly what is changing. Avoid issuing one document that calls the tenancy unchanged while a separate payment portal quietly introduces new charges.
Example: a later rent date protects the review time
Suppose rent is due on the first and notice is given on February 10 for March 1. That does not supply 30 days. Plan for a later permitted due date and verify the agreement. Moving $1,400 to $1,470 is a $70 or 5% increase; the amount calculation is separate from the timeline and contract analysis.
Before the notice goes out
Check that all tenants receive the written terms and retain delivery evidence. For affordable or otherwise regulated housing, verify the program's rent restrictions and procedures first. Preserve the reason, old and new terms, calculation and signed notice. If the tenant challenges the change, review the notice and underlying agreement before treating the proposed difference as a debt. Do not add a possession demand to this continuing-tenancy document.
Official sources and updates
Dated caps apply only to the periods stated. Check the official sources before preparing a later increase.