Dangerous Dog Declaration in Colorado: What Every Owner Needs to Know

A knock from animal control or a summons in the mail can be one of the most stressful moments you will face as a dog owner in Colorado. The state’s dangerous dog law carries real criminal consequences — from misdemeanor charges to felonies — and the process moves through the court system, not just a local administrative office.

Understanding exactly how a dangerous dog declaration in Colorado works, what triggers it, and what options you have can make a meaningful difference in the outcome for you and your dog. This guide walks you through every stage of the process so you know what to expect and how to respond.

What Makes a Dog “Dangerous” Under Colorado Law

Section 18-9-204.5 of the Colorado Revised Statutes makes it a crime to own or have any interest in, or control over, a dangerous dog. Before you can understand the declaration process, you need to know exactly what the law considers a dangerous dog.

Colorado statute defines a “dangerous dog” as one that has inflicted bodily or serious bodily injury upon or has caused the death of a person or domestic animal; or has demonstrated tendencies that would cause a reasonable person to believe that the dog may inflict injury upon or cause the death of any person or domestic animal; or has engaged in or been trained for animal fighting as described by statute.

Two key injury thresholds matter here, and the law defines them precisely:

• Bodily injury means any physical injury that results in severe bruising, muscle tears, or skin lacerations requiring professional medical treatment or any physical injury that requires corrective or cosmetic surgery.
• Serious bodily injury has the same meaning as defined in section 18-1-901(3)(p) of the Colorado Revised Statutes, which generally covers injuries involving a substantial risk of death, permanent disfigurement, or protracted loss of a body part or organ.

The statute also covers animal-on-animal harm. Any owner who violates the dangerous dog provisions whose dog injures or causes the death of any domestic animal commits a class 2 misdemeanor.

Important Note: The law’s definition of “dog” is broader than you might expect. “Dog” means any domesticated animal related to the fox, wolf, coyote, or jackal. Hybrid animals that fall into this category can be subject to the same statute.

Importantly, Colorado law does not allow breed-specific regulation. Nothing in this section shall be construed to prohibit a municipality from adopting any rule or law for the control of dangerous dogs; except that any such rule or law shall not regulate dangerous dogs in a manner that is specific to breed. This means no city or county in Colorado can label your dog dangerous simply because of its breed — the designation must be based on behavior or a demonstrated threat. If you want to understand which animals are considered dangerous in Colorado more broadly, the dangerous animals in Colorado overview provides helpful context.

Who Can File a Dangerous Dog Complaint in Colorado

The dangerous dog process in Colorado is a criminal matter, which means it does not begin with a neighbor filing a civil petition. Instead, the process is initiated by authorized enforcement authorities.

Most Colorado counties and cities allow residents to file complaints about at-large or aggressive animals, and animal control officers can issue warnings and citations to the dog’s owner. That complaint, however, is the starting point for an investigation — not a declaration itself.

Once a complaint is received, several types of officials and agencies may become involved:

• Local animal control officers — employed by counties and municipalities, they are typically the first responders to bite reports and aggressive behavior complaints.
• Law enforcement officers — “Law enforcement” means a fully P.O.S.T.-certified peace officer within their jurisdiction, including a sheriff, undersheriff, or deputy sheriff; a police officer; a town marshal or deputy town marshal; a Colorado State Trooper; or a Colorado Bureau of Investigation agent.
• Bureau of Animal Protection (BAP) commissioned agents — for unlawful ownership of a dangerous dog, a commissioned agent who is acting under the authority of applicable local or county ordinances may conduct an investigation of an allegation.

Animal control investigations can uncover evidence you might miss, like previous complaints or violations. This means that even if a single incident triggered the complaint, investigators will look at your dog’s full history before a charge is pursued.

Pro Tip: A written letter or email to a neighbor creates a paper trail. If the issue later becomes a legal matter, documented notice that the owner was aware of the problem strengthens the position of the reporting party significantly. As an owner, this also means you should document any context — such as provocation — immediately after any incident involving your dog.

In rural areas of Colorado, the process may look slightly different. In rural areas where animal control coverage is limited, the county sheriff’s office often handles at-large animal complaints. If you live outside a city or town, your county sheriff’s office is likely the primary enforcement contact.

How the Dangerous Dog Declaration Process Works in Colorado

Unlike some states that use a civil administrative hearing to declare a dog dangerous, Colorado routes dangerous dog cases through the criminal court system. Understanding this distinction is essential because it shapes every aspect of the process, from your rights to the burden of proof.

The process generally unfolds in these stages:

1. Incident and complaint — An attack, injury, or threatening behavior is reported to animal control, law enforcement, or the Bureau of Animal Protection.
2. Investigation — Officers gather evidence, interview witnesses, and review prior complaints. Animal control reports obtained through a public records request can reveal previous complaints, bite reports, or tickets involving the same dog or owner.
3. Summons and complaint issued — If investigators believe a violation has occurred, a summons and complaint is issued to you as the owner.
4. Dog may be impounded — Upon taking an owner into custody for an alleged violation of this section or the issuing of a summons and complaint to the owner, the owner’s dangerous dog may be taken into custody and placed in a public animal shelter, at the owner’s expense, pending final disposition of the charge against the owner.
5. Court proceedings — The case is heard in a Colorado court, where a judge or jury determines guilt.
6. Conviction or plea — A dangerous dog designation becomes official upon a guilty verdict, guilty plea, or deferred judgment. You will receive the court order from the court after conviction or plea agreement that states you need to register your dangerous dog. The court order is the official decision made by the judge that designates your animal as a dangerous dog.

If you are released on bail while the case is pending, the court may impose conditions involving your dog. The court may require, as a condition of bond, that the owner’s dangerous dog be placed by an impound agency at the owner’s expense in a location selected by the impound agency including a public animal shelter, licensed boarding facility, or veterinarian’s clinic, pending final disposition of the alleged violation.

You should also be aware of a strict deadline regarding impounded animals. A dog that is not claimed by its owner within five days after being eligible for release from impoundment for investigation of a charge of unlawful ownership of a dangerous dog is deemed abandoned and may be disposed of as the impound agency deems proper. Do not delay in responding to notices about your dog’s impoundment.

Your Rights as a Dog Owner During the Process in Colorado

Because Colorado’s dangerous dog law is a criminal statute, you have the same constitutional protections that apply in any criminal case. This is one of the most important things to understand if your dog is the subject of a complaint.

Your core rights during the process include:

• The right to contest the charges — You are not automatically found guilty. The state must prove the violation through the criminal court process.
• The right to a jury trial — Depending on the severity of the charge, you may have the right to have your case decided by a jury rather than a judge alone.
• The right to legal representation — You may hire an attorney at any stage. Given the potential for felony charges and the possible destruction of your dog, retaining counsel early is strongly advisable.
• The right to present affirmative defenses — Colorado law specifically recognizes several defenses that can defeat a dangerous dog charge (see the next section).

You also have rights related to your impounded dog’s care costs. The owner or custodian of an animal that has been impounded may prevent disposition of the animal by an impound agency by filing a payment for impoundment, care, and provision costs with the court in an amount determined by the impound agency to be sufficient to provide for the animal’s care and provision at the impound agency for at least thirty days, including the day on which the animal was taken into custody.

Key Insight: The court shall order an impound agency to refund to the owner or custodian all impoundment, care, and provision payments made for the animal if, after trial, a judge or jury enters or returns in favor of the owner or custodian a verdict of not guilty for all charges related to the original impoundment of the animal. Paying boarding costs during the case does not mean you forfeit those funds if you win.

However, there is a critical warning about failing to pay. Failure to pay the impoundment, care, and provision costs results in the forfeiture of the right to contest those costs and any ownership rights to the animal in question. Staying current on boarding fees is not just a financial matter — it is a legal one that affects your ownership rights.

What Happens After a Dog Is Declared Dangerous in Colorado

A conviction under C.R.S. 18-9-204.5 triggers a set of mandatory court orders and ongoing obligations that you must follow for as long as you own the dog. These requirements are not optional — violating them constitutes a separate criminal offense.

The court shall order any owner of a dangerous dog who has been convicted to confine the dangerous dog in a building or enclosure designed to be escape-proof and, whenever the dog is outside of the building or enclosure, keep the dog under the owner’s control by use of a leash. The owner shall post a conspicuous warning sign on the building or enclosure notifying others that a dangerous dog is housed there. In addition, if the conviction is for a second or subsequent offense, the dangerous dog shall also be muzzled whenever it is outside of the building or enclosure.

Beyond confinement, you will be required to register your dog with the state. If you have received a court order after conviction or plea agreement that states you need to register your dangerous dog, you must register your dog with the Bureau of Animal Protection.

The registration process involves several specific steps:

• The dangerous dog form must be completed by the defendant/owner and the veterinarian upon completion of the microchip implant. Once the microchip is implanted, the defendant/owner must complete the online form. After all information has been received, the Bureau will provide an In Compliance Letter that you can provide to the court to show compliance with the dangerous dog registration.
• Application processing can take between one and two weeks.
• You will need to upload a copy of the full court order, a color photo, and a microchip verification form. The Bureau cannot process incomplete submittals.
• A person who is ordered to identify their dangerous dog through microchip implantation shall pay to the bureau a nonrefundable dangerous dog microchip license fee of fifty dollars.

The bureau maintains a statewide dangerous dog registry consisting of a database of information concerning microchip types and placement by veterinarians and licensed shelters in dangerous dogs. The commissioner may promulgate such rules as may be necessary for the implementation of this section.

You are also required to disclose the dog’s status to any future owner. Prior to a change, transfer, or termination of ownership of a dangerous dog, you must disclose in writing to the prospective owner that the dangerous dog has been the subject of a conviction of a violation of this section.

Important Note: In the most serious cases, the court may order euthanasia. Unless you successfully appeal your conviction, upon exhaustion of your right to appeal, the dangerous dog will be destroyed by euthanasia administered by a licensed veterinarian if the owner has pled to or been found guilty of a violation that resulted in serious bodily injury to a person, death to a person or domestic animal, or a second or subsequent violation for the same dog causing bodily injury to a person or death to a domestic animal.

For more context on how dangerous animals are treated under Colorado law, including wildlife and other species, see the guide to dangerous animals in Colorado Springs.

How to Contest a Dangerous Dog Declaration in Colorado

Colorado law provides you with meaningful tools to fight a dangerous dog charge. Because the case proceeds as a criminal matter, the prosecution must prove the elements of the violation beyond a reasonable doubt — and you are entitled to raise affirmative defenses that the law explicitly recognizes.

The statute sets out several affirmative defenses available to dog owners. Recognized defenses include: at the time of the attack, the victim was committing or attempting to commit a criminal offense against you and the attack did not occur on your property; if your dog’s attack caused injury to or the death of a person, the victim of the attack was committing or attempting to commit a criminal offense against your property or someone on your property; and the victim of the attack tormented, provoked, abused, or inflicted injury upon your dog in an extreme manner that resulted in the attack.

There is also a specific exemption for working dogs. The dangerous dog provisions do not apply to any dog that inflicts injury upon or causes the death of a domestic animal while the dog was working as a hunting dog, herding dog, or predator control dog on the property of or under the control of the dog’s owner, and the injury or death was to a domestic animal naturally associated with the work of such dog.

One important limitation: the affirmative defenses shall not apply to any dog that has engaged in or been trained for animal fighting. If your dog has a history of organized fighting, these defenses are not available.

Defense	Key Requirement	Limitation
Victim committing a crime against the owner	Attack must not have occurred on owner’s property	Not available for fighting dogs
Victim committing a crime against the owner’s property	Victim must have been on or threatening the property	Not available for fighting dogs
Victim provoked or tormented the dog	Provocation must have been extreme and caused the attack	Not available for fighting dogs
Working dog exemption	Dog must have been actively working; injury to naturally associated animal	Does not apply to people or pets

Building a strong defense often requires more than citing the statute. Certified animal behaviorists can look closely at what happened during an attack and give expert opinions about the dog’s behavior and the owner’s response. Veterinary behaviorists can testify about whether the dog showed signs of aggression that a reasonable owner should have recognized — or, equally important, whether the dog did not show such signs prior to the incident.

These charges can be defended in the court of law depending on the circumstances in which an attack occurred. The law understands each case is unique, including the details behind why an attack took place.

Pro Tip: You need to hire an attorney for dangerous dog cases as soon as possible, or else you risk losing your dog — there is a 10-day deadline to request a hearing in some local jurisdictions. Deadlines in these cases are strict, and missing them can waive important rights.

Understanding how behavior-based designations work in other states can also help you frame your defense arguments. Reviewing how most dangerous dog breeds are assessed behaviorally versus by breed provides useful background on the science courts and experts may consider.

Penalties for Violating Dangerous Dog Requirements in Colorado

Colorado’s penalties for dangerous dog violations are tiered based on the severity of the harm caused and whether you have prior convictions. These penalties apply both to the original incident and to any failure to comply with post-conviction requirements.

Criminal penalties by severity of harm:

• Bodily injury to a person: Any owner whose dog inflicts bodily injury upon any person commits a class 2 misdemeanor. Penalties include a fine of up to $750.
• Serious bodily injury to a person (first offense): If your dog inflicts serious bodily injury on a person, you have committed a class 1 misdemeanor if it is your first offense.
• Serious bodily injury (second or subsequent offense): Any owner involved in a second or subsequent violation commits a class 6 felony.
• Death of a person: Any owner whose dog causes the death of a person commits a class 5 felony.
• Injury or death of a domestic animal: Any owner whose dog injures or causes the death of any domestic animal commits a class 2 misdemeanor.

In addition to criminal penalties, you will be ordered to pay restitution. If you are convicted of owning a dangerous dog, the court will order you to pay restitution to the other party or parties involved. Restitution for damaged property shall be in an amount equal to the greater of the fair market value or the replacement cost of such property before its destruction, plus any actual costs incurred in replacing such property.

Restitution for a dead or injured domestic animal shall be equal to the greater of the fair market value or the replacement cost of the domestic animal on the date, but before the time, the animal was injured or destroyed, plus any reasonable and necessary medical expenses incurred in treating the animal and any actual costs incurred in replacing the injured or destroyed animal.

You also remain financially responsible for your dog while it is held. The owner is liable for the total cost of board and care for a dog placed in an impound facility pursuant to the statute.

Ongoing compliance violations carry their own consequences. Failing to confine your dog in an escape-proof enclosure, failing to use a leash, failing to post the required warning sign, or failing to register the dog with the Bureau of Animal Protection can each result in additional criminal charges on top of your original conviction.

Common Mistake: Many owners assume that paying a fine resolves the matter. In Colorado, a dangerous dog conviction creates permanent ongoing obligations — including microchip registration, confinement requirements, and mandatory disclosure to future owners. There is a long list of both practical and financial consequences for owning a dangerous dog. Practical consequences include using a muzzle and leash on the dog at all times, having a warning sign on the owner’s property regarding the dangerous dog, and microchipping the dog as a way to identify that the dog is dangerous.

The statewide reach of these requirements also means that local ordinances can layer additional rules on top of the state law. The Colorado General Assembly has declared that dangerous dogs are a serious and widespread threat to the safety and welfare of citizens throughout the state because of the number and serious nature of attacks by such dogs, and that the regulation and control of dangerous dogs is a matter of statewide concern. Cities and counties can go further — they just cannot make their rules breed-specific.

If you are navigating a dangerous dog situation in Colorado and want to understand the broader landscape of animal-related legal issues, the following resources may be helpful: the guide to dangerous animals in Arizona offers a comparative look at how neighboring states approach similar issues, and if you are concerned about wildlife interactions that may have contributed to your dog’s behavior, the overview of dangerous animals in Yellowstone and dangerous animals in Wyoming cover predator encounters that sometimes provoke dogs in rural Colorado communities.

A dangerous dog declaration in Colorado is a serious legal matter that touches criminal law, animal welfare, and your rights as a property owner. Knowing the definitions, understanding the process, and acting quickly — especially regarding impoundment deadlines and hearing requests — gives you the best chance of protecting both your dog and your legal standing. When in doubt, consult a Colorado criminal defense attorney who has experience with animal law as early in the process as possible.