How to evict a tenant with no lease in Colorado

This situation arrives in a few predictable forms. A handshake arrangement with someone you knew. A tenant whose written lease expired years ago and who simply kept paying. A relative who moved in "for a few months." A roommate left behind when the named tenant moved out. In every one of these, an owner eventually asks the same question: they never signed anything, so can I just tell them to go?

Almost always, no.

No lease still means a tenancy

Colorado does not require a written lease to create a tenancy. Where someone occupies property with the owner's permission and pays rent — in money, and sometimes in other forms — the law generally treats it as a month-to-month tenancy on the terms the parties actually followed. The rent is whatever was being paid. The due date is whenever it was being paid. And the tenant gets the protections that come with a tenancy.

What you lose by not having a lease is not the tenant's obligations. It is your evidence of them, and any term you would have added.

What notice you have to give

To end a month-to-month tenancy in Colorado you generally need to give 21 days' written notice — and, under the just-cause framework, most residential terminations now also require a qualifying reason. "I want the property back" is not automatically sufficient.

The notice itself must still be correct and correctly served, exactly as it would be with a written lease. Our guide to Colorado eviction notices covers form and service; if the occupant stops paying, the pay-or-quit route applies to them the same as anyone else.

The awkward cases

Family members. The hardest version of this. A relative who has lived in your property for months, contributed to bills, received mail there and treated it as home may well have acquired a tenancy — even if no one ever used the word "rent." Asking them to leave, and them refusing, may leave you with no option but the courts.

Guests who became residents. There is no bright line where a guest becomes a tenant. Length of stay, payment of any kind, mail delivery, and whether they have a key all matter. Err on the side of assuming they have rights.

Holdover tenants. A tenant whose fixed-term lease ended but who stayed on with your acceptance generally converts to month-to-month on the old terms. This is usually good news: the lease's substantive terms often survive.

Roommates left behind. If an unnamed occupant remains after the tenant on the lease departs, their status depends on whether you accepted them — including whether you took their money. Accepting rent from someone tends to make them a tenant.

Build the record you never created

Without a lease, a court is going to reconstruct the arrangement from whatever evidence exists. Before you do anything else, gather it:

• Bank records or transfer histories showing what was paid, when, and by whom
• Texts, emails or messages discussing rent, repairs, or the terms of the arrangement
• Anything showing the date occupancy began
• Any written communication about ending the arrangement

This record establishes both that a tenancy exists and what its terms are — which cuts both ways, and is usually more helpful to the owner than they expect.

What you absolutely cannot do

The temptation is strongest precisely here, where the arrangement felt informal and the occupant seems to have no paperwork to stand on. Resist it. Changing the locks, removing possessions, shutting off utilities, or making the property unliveable are illegal in Colorado regardless of whether anything was signed. Doing so turns a straightforward possession case into a liability claim against you.

The cheapest exit is usually a conversation

Formal process is slow and expensive, and in no-lease situations the relationship is often personal, which makes it worse. A frank conversation, a realistic deadline, and sometimes a modest relocation payment resolve these faster and cheaper than a court will — and preserve a relationship that a filing tends to end permanently.

If you own property around Westminster, Thornton or anywhere in the north metro and you are in this position, it is worth a conversation before you send anything in writing.

This article is general information, not legal advice. Colorado's landlord-tenant laws change and can vary by situation. Always verify current requirements and consult a licensed Colorado attorney before acting on any of it.