Montana Rent Increase Notice Requirements

Montana's Residential Landlord and Tenant Act does not limit the amount of a rent increase, and no rent-control law exists statewide. A rent increase is treated as a change of terms in a periodic tenancy. Under Mont. Code Ann. § 70-24-311, a landlord who substantially modifies the agreement must give a month-to-month tenant '30 days' written notice' and a week-to-week tenant 7 days. The same 30-day notice frame mirrors the termination notice in § 70-24-441, so a landlord effectively gives 30 days before a higher rent takes effect on a month-to-month tenancy. Fixed-term leases lock the rent until the term ends.

No specific statutory penalty. An increase imposed without the required 30-day (or 7-day) written notice is unenforceable for that period; the tenant continues paying the prior rent until proper notice expires.