Ending a Month-to-Month Tenancy in Colorado: How Much Notice You Actually Owe

“Month-to-month” sounds like it should mean a flat, short notice period no matter what. It doesn’t. Colorado ties the notice period to how long the tenant has actually lived there, and a lease that hardcodes a single number is very likely wrong for at least some of its tenants.

The notice period scales with tenancy length

Colorado’s notice-to-terminate statute sets longer notice for longer tenancies: a tenancy of a few months up to six months generally needs 21 days’ notice; a tenancy between six months and a year generally needs 28 days’; a tenancy of a year or more generally needs 91 days’. A lease or internal process that applies “30 days, always” isn’t matching any of these tiers correctly — it’s either too short for a longer-tenured tenant or unnecessarily long for a newer one.

The notice has to say when, not just that

The written notice needs to describe the property and state the specific date the tenancy will terminate, and it has to be signed by the party giving it (or their agent or attorney). A notice that says “your tenancy will end soon” without a specific termination date, delivered before the current rental period ends, doesn’t satisfy the requirement.

The 12-month tenant isn’t just a longer-notice case — it’s a different rule entirely

Once a tenant has been in the unit for 12 or more months, ending a month-to-month tenancy isn’t just about hitting the 91-day mark — it’s also subject to Colorado’s for-cause requirement (HB24-1098), the same rule covered in The 6 No-Fault Reasons Colorado Landlords Can Still Use to Not Renew. A landlord ending a long-standing month-to-month tenancy needs both the right notice length and a qualifying reason (or an applicable exemption) — getting the notice period right doesn’t substitute for the reason requirement, and vice versa.

Why this trips up landlords with mixed tenant tenures

A landlord managing several month-to-month units with tenants at different tenure lengths can’t use one template notice for all of them. A tenant at month 4 and a tenant at month 14 are on genuinely different rules — one needs 21 days and no stated reason, the other needs 91 days, a qualifying reason, and possibly a check against the for-cause exemptions.

What to check before sending a notice to terminate

• How long has this specific tenant actually lived in the unit — not just their current lease term, but total tenancy?
• Does the notice period match that tenant’s tier (21/28/91 days), not a flat default?
• Does the notice state a specific termination date and identify the property?
• If the tenant has been there 12+ months, does the non-renewal also have a qualifying reason under the for-cause rule?

The bottom line

A single “standard notice period” doesn’t work across a portfolio of tenants with different tenure lengths. A Renewal Compliance Check reviews your notice-to-terminate process against the tenure-based tiers and, where it applies, the for-cause requirement layered on top.

LeaseCheck for Landlords is an educational lease-compliance screening tool. It is not a law firm and does not provide legal advice. Colorado rental laws change; confirm specifics for your situation with a licensed attorney.