Last reviewed September 2026. Colorado eviction statutes and court forms change frequently, so landlords should confirm current requirements before serving notice or filing a case.
A prohibited pet, unauthorized occupant, repeated disturbance, or serious property damage can create a difficult situation for a Colorado landlord. A lease violation may support eviction, but the landlord must identify the correct statutory category before serving notice. Ordinary material violations, repeat violations, substantial violations, and nuisance or property-damage claims do not all follow the same process.
At Anzen Legal Group, our Fort Collins landlord attorneys represent landlords and property owners, not tenants. We help landlords compare the conduct to the lease and Colorado statutes, determine whether the tenant must receive an opportunity to cure, and prepare for an eviction case when the violation continues.
Before labeling conduct a substantial violation or serving a notice to terminate, call Anzen Legal Group at 970-893-8857. Choosing the wrong category can give the tenant a defense and delay recovery of the property.
What Is the Short Answer Under Colorado Law?
Yes. A material violation of an enforceable lease term can provide cause for eviction under C.R.S. section 13-40-104(1)(e). In many cases, however, the landlord must first give the tenant a written demand and an opportunity to correct the problem. If the tenant cures the violation within the applicable period, the landlord generally cannot continue that eviction based solely on the cured conduct.
Different procedures apply when the tenant repeats a violation after receiving proper notice or engages in conduct meeting Colorado’s narrow definition of a substantial violation. The facts and prior notice history therefore matter as much as the language of the lease.
If the tenant’s primary lease violation is failure to pay rent, see our post on evicting a tenant for unpaid rent in Colorado.
What Is a Material Lease Violation?
A material lease violation is a breach significant enough to support enforcement of the landlord’s right to possession. Examples may include an unauthorized occupant, an animal prohibited by an enforceable lease provision, an unapproved use of the property, or other conduct that materially violates a lawful covenant. Whether a breach is material depends on the lease language, the conduct, applicable statutes, and the surrounding circumstances.
A landlord should identify the specific lease provision, describe what occurred, and preserve evidence showing why the conduct violates that provision. Vague statements that the tenant has been difficult or has broken the rules may not give adequate notice of what must be corrected.
Must the Tenant Receive an Opportunity to Cure in Colorado?
For an ordinary material lease violation, generally yes. The current JDF 99A Demand for Compliance allows the landlord to identify the lease term, explain the violation, and give the tenant the applicable period to comply or surrender possession.
The standard period is 10 days for many residential agreements. The current form also identifies a five-day period for qualifying exempt residential agreements, three days for employer-provided housing agreements, and 30 days for CARES Act properties. The correct period must be determined from the tenancy and property rather than selected based only on how serious the landlord considers the conduct.
What Is a Repeat Lease Violation?
A repeat violation involves conduct that occurs after the tenant received proper notice of an earlier lease violation. Colorado law treats repeat violations differently under C.R.S. section 13-40-104(1)(e.5) because the tenant has already been given an opportunity to correct the identified conduct. The current JDF 99B Notice to Terminate Tenancy provides a 10-day move-out period for a repeat violation and identifies a 30-day period for a qualifying CARES Act property.
A landlord relying on a repeat violation should preserve the prior demand, proof of service, evidence of the earlier conduct, and evidence showing that the violation occurred again. The prior and later conduct must be evaluated carefully before the landlord assumes that the repeat-violation procedure applies.
What Is a Substantial Violation in Colorado?
A substantial violation is not simply a serious or frustrating breach. C.R.S. section 13-40-107.5 defines specified conduct that can support termination without the ordinary opportunity to cure. The statutory category includes conduct on or near the premises that endangers a person or willfully and substantially endangers property belonging to the landlord, a co-tenant, or a person living on or near the premises. It also includes specified violent or drug-related felonies and certain criminal acts that qualify as public nuisances and carry the required potential punishment.
When the statutory definition is satisfied, the form identifies a three-day move-out period. Because that procedure removes the ordinary opportunity to cure, courts may closely examine whether the alleged conduct actually fits the statute. Landlords should avoid using the substantial-violation label as a shortcut for conduct that belongs under another provision.
Can Nuisance, Disturbing Conduct, or Property Damage Support Eviction in Fort Collins, Colorado?
Colorado’s for-cause statute recognizes conduct that creates a nuisance or disturbance interfering with the quiet enjoyment of other tenants or occupants of the property or residents of immediately adjacent property. Under C.R.S. section 13-40-104(1)(j), the statute also refers to the landlord’s quiet enjoyment when the landlord lives on the same or immediately adjacent property. Negligent or malicious damage to the housing accommodation may also support this ground. The current JDF 99A includes a separate option for disturbing conduct, which should not automatically be confused with a substantial violation.
Reports from neighbors, photographs, repair records, incident reports, warnings, and communications may become important. A landlord should document who observed the conduct, when it occurred, how it affected the property or other occupants, and what steps were taken in response.
Can Victim-Survivor Protections Affect a Lease-Violation Eviction?
Yes. Colorado law can prevent a landlord from relying on an alleged material, repeat, substantial, nuisance, or disturbing-conduct violation when documented unlawful sexual behavior, stalking, domestic violence, or domestic abuse caused or resulted in the conduct attributed to the victim-survivor. See C.R.S. section 13-40-104(4) and 13-40-107.5(5)(c). These protections do not prevent an eviction claim against a tenant who perpetrated the violence or abuse.
Separate victim-survivor protections address early lease termination, lock changes, and reasonable safety precautions. House Bill 25-1168 expanded the forms of documentation a victim-survivor may provide and prohibits adverse action for qualifying lock changes or other reasonable safety measures. Before treating an unauthorized occupant, altered lock, disturbance, or related conduct as a lease violation, a landlord should determine whether these protections apply.
What Must A Lease-Violation Notice Say in Colorado?
The notice should identify the lease provision at issue, describe the conduct with enough detail for the tenant to understand the alleged violation, state whether and how the tenant may cure, and provide the correct deadline. It should also identify the premises and comply with current language and tenant-rights requirements.
The landlord should use the form that matches the legal theory. JDF 99A is designed for curable compliance demands, while JDF 99B addresses repeat violations and substantial violations. Using the wrong notice can create uncertainty about whether the tenant had a right to cure and whether the landlord may proceed.
How Must the Notice Be Served?
Service requirements depend on the notice and circumstances. The current JDF 99B permits posting after two unsuccessful personal-service attempts for a repeat violation, while only one unsuccessful attempt is required before posting for a substantial violation. Because forms can change, landlords should use the current version when preparing and serving the notice.
The landlord should record each attempt, the date and method of service, and the person served. Because the notice period is calculated from completed service, a defective or poorly documented service process can affect when the landlord is permitted to file.
What Happens if the Tenant Corrects the Violation?
If an ordinary material violation is corrected within the applicable cure period, the landlord generally cannot continue the eviction based solely on that cured violation. The landlord should document what changed and continue preserving the original demand and proof of service in case similar conduct occurs again.
Whether later conduct qualifies as a repeat violation can depend on the relationship between the first notice and the new conduct. As experienced lease-violation attorneys, we can evaluate whether the prior demand is sufficient or whether a new demand should be served.
What Evidence Is Important in a Contested Eviction Case Based on a Lease Violation?
A tenant may dispute the conduct, argue that the cited lease term does not apply, challenge whether the violation was material, or assert that the notice or service was defective. The landlord should be prepared with the signed lease and amendments, the demand or termination notice, proof of service, photographs or video, communications, witness information, inspection records, police or incident reports when appropriate, and evidence showing whether the tenant cured or repeated the conduct.
The quality of the documentation can determine whether the court sees an enforceable lease violation or only an unresolved factual disagreement. Records created when events occur are generally more useful than a summary reconstructed immediately before the hearing.
Can a Landlord Change the Locks After the Notice Expires?
No. Expiration of the notice does not itself authorize the landlord to remove the tenant. If the tenant remains, the landlord generally must file an FED action, serve the summons and complaint, obtain a judgment for possession, and request a writ of restitution when necessary.
The sheriff, not the landlord, restores possession under the writ. Changing locks, shutting off utilities, removing belongings, or physically excluding the tenant before the lawful process is complete can expose the landlord to additional claims.
Why Should a Landlord Have the Notice Reviewed First?
Lease-violation cases often turn on classification. An ordinary material breach usually carries a right to cure. A repeat violation depends on a sufficient earlier notice and later conduct. A substantial violation requires facts satisfying a specific statutory definition. The wrong classification can undermine the notice and force the landlord to reconsider the case after time has already passed.
Our Fort Collins eviction lawyer and landlord attorney page explains the broader Colorado eviction process and the state’s for-cause requirements. For a particular lease violation, counsel can evaluate the agreement, notice history, evidence, and statutory ground before the landlord acts.
Speak With a Fort Collins Landlord Attorney About a Lease Violation
A landlord does not have to wait until the dispute reaches court. Early review can help determine whether the conduct supports eviction, whether the tenant must receive an opportunity to cure, which notice applies, and what evidence should be preserved.
Anzen Legal Group represents landlords and property owners, not tenants, in Colorado eviction and landlord-tenant matters.
Call 970-893-8857 to speak with a Fort Collins eviction attorney about a lease violation and the appropriate next step.
This article is general information about Colorado law, not legal advice. Reading it does not create an attorney-client relationship with Anzen Legal Group, and the statutes and forms discussed here change frequently. Consult a licensed Colorado attorney about your specific situation before serving a notice or filing an eviction.
