Does Colorado Follow the One Bite Rule? What Dog Bite Victims Need to Know
June 2, 2026
If a dog bites you in Colorado, you may wonder whether the owner can simply claim the animal had never shown aggression before and walk away without consequences. That assumption — rooted in a legal concept called the one bite rule — does not reflect how Colorado law actually works.
Colorado takes a notably stronger stance on dog owner accountability than many other states. Understanding where the one bite rule fits, where it does not, and what legal paths are available to you can make a significant difference in how your case unfolds.
Important Note: This article is for informational purposes only and does not constitute legal advice. If you have been bitten by a dog in Colorado, consult a qualified personal injury attorney to discuss your specific situation.
Does Colorado Follow the One Bite Rule
Colorado does not follow the one bite rule in dog bite cases. Instead, the state operates under a strict liability rule for injuries or deaths caused by dogs. This is a meaningful distinction for anyone who has been injured in an attack.
Under the one bite rule used in some states, dog owners are not typically liable for bite injuries if their dogs have never bitten anyone or shown signs of aggressive behavior. Colorado does not give owners a “free pass” for a dog’s first bite the way one-bite states do.
Colorado enacted a specific dog bite liability statute that provides significantly stronger protection for bite victims than the common law one bite rule that still governs dog bite claims in many other states. Colorado Revised Statute Section 13-21-124 imposes strict liability on dog owners for bites that occur in public places or in private places where the victim was lawfully present, without requiring any showing that the owner knew the dog was dangerous.
It is worth noting, however, that the one bite doctrine has not entirely disappeared from Colorado law. The one bite doctrine is the common law remedy for dog bites that predated the strict liability statute codified by C.R.S. § 13-21-124. This doctrine only allowed for liability imposed on a dog owner for harm caused if the owner had reason to believe the dog might bite — in other words, the dog owner could only be held liable if the dog had bitten before. However, after 2004 this doctrine has become somewhat of an illusion. The statute is now the primary vehicle for most dog bite claims in the state, and prior knowledge is no longer a prerequisite for liability.
How the One Bite Rule Works in Colorado
The term “one bite rule” comes from a legal doctrine that requires proof that the dog owner knew or should have known about their dog’s dangerous tendencies. According to Cornell Law School, “the one bite rule often arises in lawsuits involving bites from domesticated animals.” This rule is a scienter requirement under common law that requires the plaintiff to first bear the burden of proof in pleading and proving that the dog owner either knew or was negligent in not knowing that the dog had a propensity to injure people.
Colorado replaced this framework with a statutory approach. C.R.S. § 13-21-124 imposes strict liability on owners when their dog bites a person who is lawfully on public or private property. The owner remains liable even if the dog never bit someone or displayed violent tendencies previously.
There are two types of dog bite claims in Colorado: strict liability and negligence-based. Colorado has a strict liability rule in cases where dogs cause serious injuries, such as broken bones, or death. This means owners are responsible for their dogs’ bites, even if the dogs have never bitten anyone before. It does not matter whether an owner knew their dog was dangerous or not.
Colorado also allows negligence-based claims for less severe injuries. In a negligence-based claim, the victim must show that the owner failed to take reasonable care to prevent the bite. This is where the residual logic of the one bite rule can still surface — particularly when a victim is pursuing non-economic damages or when the injury does not meet the serious bodily injury threshold required by the statute. You can read more about how Colorado handles dog bite incidents in detail, including the criminal exposure dog owners may face.
Key Insight: Colorado’s strict liability statute covers only actual dog bites. Some dogs are quite large and can cause a significant injury without even biting. Colorado’s statute specifically applies to dog bites, so if a dog attacks a person by charging but does not bite her, that person would likely not have a claim under the statute. That individual might have a claim for negligence instead.
What Victims Must Prove Under the One Bite Rule in Colorado
Because Colorado primarily operates under strict liability rather than the one bite rule, what you need to prove depends on the path your claim takes.
Under the strict liability statute (C.R.S. § 13-21-124):
Strict liability under Colorado dog bite law means that an injured person does not have to prove that the owner of the dog was negligent, just that serious bodily injury or death occurred. Specifically, you must establish:
- You were lawfully on public or private property at the time of the bite
- A dog bit you (not merely knocked you down or scratched you)
- The bite resulted in serious bodily injury or death
As per C.R.S. § 18-1-901, “serious bodily injury” includes harm posing a substantial risk of death, causing permanent disfigurement, or impairing bodily functions. This also includes a substantial risk of protracted loss or impairment of the function of any part or organ of the body, or breaks, fractures, or second-degree or higher burns.
Under a negligence-based claim:
If your injuries do not meet the serious bodily injury threshold, or if you are seeking non-economic damages such as pain and suffering, the analysis shifts. The dog bite statute does not entitle a victim to receive general damages for intangible losses. To recover full compensation for pain and suffering, a dog bite victim has to prove that the defendant was negligent or should have known that the dog had the tendency to bite people.
Negligence looks at conduct rather than the bite alone. This includes whether the owner failed to restrain the dog, ignored leash laws, allowed a dangerous animal to roam, or permitted a substantial risk to remain on the dog owner’s property.
What Counts as Prior Knowledge in Colorado
Under the strict liability statute, prior knowledge is not required — but it becomes highly relevant when you are pursuing non-economic damages or a negligence-based claim. Proving that an owner knew or should have known about a dog’s dangerous tendencies can significantly expand the compensation available to you.
In Barger v. Jimerson (1954) 130 Colo. 459, the Colorado Supreme Court held that a dog owner who is free of negligence shall nevertheless be liable for injuries and losses resulting from a dog bite, if the owner knew or should have known that the dog was dangerous prior to attack. A victim only has to prove that the dog had the tendency to bite, not that it ever actually bit anyone.
This is an important nuance. Prior knowledge does not require a documented previous bite. In Colorado, there is the ability for the plaintiff to argue that the dog had a propensity to bite, and therefore the owner “knew or should have known” that the dog was dangerous. As the Court stated in Barger v. Jimerson: “There is no evidence in this case that the dog in question had ever bitten anyone before, but its ferocious and violent nature as daily exhibited to many people, especially the neighbors, was such as to put prudent people on guard.”
Evidence that can establish prior knowledge includes:
- Complaints from neighbors about the dog’s aggressive behavior
- Animal control records or prior incident reports
- The owner’s own statements about the dog being territorial or reactive
- A history of lunging, growling, or threatening postures toward people
- Previous bites to other animals or people
Medical records, witness statements, animal control reports, photographs, and proof that the injury occurred all play a role in establishing a dog bite claim and showing that the bite occurred.
Prior knowledge also carries a separate legal consequence. In any case in which it is alleged and proved that the dog owner had knowledge or notice of the dog’s viciousness or dangerous propensities, the court, upon a motion made by the victim or the personal representative of the victim, may enter an order that the dog be euthanized by a licensed veterinarian or licensed shelter at the expense of the dog owner. This is a significant outcome that underscores why documenting prior behavior matters. For a comparison with how other states handle this issue, see the dog bite laws in Virginia and dog bite laws in Washington.
Pro Tip: Even if a dog has no prior bite history, documented aggressive behavior — such as neighbor complaints or animal control visits — can still establish that the owner knew or should have known about the danger. Gather this evidence as early as possible after an attack.
Exceptions and Defenses to the One Bite Rule in Colorado
Colorado’s strict liability statute is broad, but it is not unlimited. Colorado’s dog bite statute identifies only six circumstances where a dog owner will not be held liable for injuries caused by their dog. Understanding these defenses helps you anticipate what an owner or their insurer may argue.
A dog owner shall not be liable to a person who suffers bodily injury, serious bodily injury, or death from being bitten by the dog: (a) While the person is unlawfully on public or private property; (b) While the person is on property of the dog owner and the property is clearly and conspicuously marked with one or more posted signs stating “no trespassing” or “beware of dog”; (c) While the dog is being used by a peace officer or military personnel in the performance of peace officer or military personnel duties; (d) As a result of the person knowingly provoking the dog; (e) If the person is a veterinary health-care worker, dog groomer, humane agency staff person, professional dog handler, trainer, or dog show judge acting in the performance of his or her respective duties; or (f) While the dog is working as a hunting dog, herding dog, farm or ranch dog, or predator control dog on the property of or under the control of the dog’s owner.
Beyond the statutory exemptions, comparative negligence is another defense owners may raise. Colorado follows a modified comparative negligence rule when determining damages in personal injury cases, including dog bite cases. If a court finds that both the dog owner and the victim share some degree of fault for the incident, the compensation awarded to the victim may be reduced proportionally to their level of fault.
The owner can argue that the injured person was partly or entirely at fault for his or her own injuries. This defense, known as comparative negligence, will reduce the injured person’s damages if that individual was partly at fault, and will extinguish them if that person was 50% or more at fault.
Common Mistake: Assuming that a “Beware of Dog” sign automatically bars all claims. The sign defense only applies under the strict liability statute. A negligence-based claim may still proceed even if a warning sign was posted, depending on the circumstances.
Dog Owner Liability Beyond the One Bite Rule in Colorado
Even when the strict liability statute does not apply — for example, because the injury did not rise to serious bodily injury — Colorado law provides other avenues for victims to pursue compensation.
Negligence claims: If the Colorado code section does not apply, there is nothing to stop an injured person from suing a dog owner under a standard negligence action. When this is the case, the injured person must meet the definition of negligence and prove his or her case accordingly. Violations of local leash laws, for instance, can serve as evidence of negligence. You can explore how Oregon and Utah handle similar negligence-based frameworks for comparison.
Premises liability: In some circumstances, a landlord may be liable — for example, if he has leased property to a dog owner and reasonably could have known that the presence of the dog creates a “clear potential for injury.”
Landlord liability: A landlord may share dog-bite liability when they have control over the property and some level of authority over the dog’s presence. This often arises when a landlord or owner knew that a dog posed a risk and failed to take reasonable steps to address it. Complaints from tenants, known aggressive behavior, or violations of lease terms related to pets can all factor into whether a landlord may be pulled into a dog bite claim.
Criminal liability: In addition to the civil suits brought by dog attack victims, criminal charges are possible as well. A person who owns or has some controlling interest in a dangerous dog is responsible for the dog’s transgressions and will face the following charges: if the dog inflicts a bodily injury — Class 2 misdemeanor; if the dog inflicts a serious bodily injury — Class 1 misdemeanor.
Non-economic damages through negligence: Victims of a dog attack may also seek compensation for non-economic damages if they can show that the owner knew or reasonably should have known of a dog’s propensity to act aggressively. Non-economic damages can include the pain of the injury and treatment, mental suffering when confronted by other dogs as a result of the attack, emotional scars, pain and suffering, disability, and other factors contributing to a loss in quality of life.
| Claim Type | Injury Threshold | Prior Knowledge Required? | Damages Available |
|---|---|---|---|
| Strict Liability (CRS 13-21-124) | Serious bodily injury or death | No | Economic damages only (medical bills, lost wages) |
| Negligence | Any injury | Yes (owner knew or should have known) | Economic + non-economic damages (pain and suffering) |
| Premises/Landlord Liability | Any injury | Yes (landlord had knowledge of risk) | Economic + non-economic damages |
What to Do After a Dog Bite in Colorado
The steps you take immediately after a dog bite can directly affect the strength of your legal claim. Acting quickly and methodically protects both your health and your right to compensation.
- Seek medical attention immediately. Address injuries promptly to prevent infection and document the extent of harm. Medical records are foundational to any dog bite claim, whether under strict liability or negligence.
- Identify the dog and its owner. It is incredibly important to acquire as much information about the owner of the animal as possible. This is similar to a car accident, so if necessary, make sure to call animal control to get a handle on the situation. At the very least, take a picture of the dog owner’s driver’s license.
- Report the incident. Notify local animal control to document the attack and investigate the dog’s vaccination and behavioral history. An official report creates a paper trail that can be invaluable later.
- Gather evidence at the scene. Take photos of injuries, the dog, and the location. Collect contact information from witnesses and the dog’s owner.
- Document all expenses. Keep records of medical bills, missed workdays, and other costs related to the attack. This documentation supports your economic damages claim.
- Contact an attorney promptly. Colorado law typically gives you two years from the date of the dog bite to file a lawsuit. If you wait too long, the court will likely dismiss your case, and you could lose your right to sue for compensation.
Most dog bite claims are covered under the dog owner’s homeowner’s or renter’s insurance policy. Policies typically have limits on how much they will pay, ranging from $100,000 to $500,000 or more. Knowing this can help you understand the practical path toward recovering compensation.
Pro Tip: Consider that most dog bites do not happen at houses — they happen on trails or at parks. If you do not have information about the owner, you will not be able to pursue a legal case. Always try to gather owner information before leaving the scene.
Colorado’s approach to dog bite liability is designed to protect victims, not reward negligent ownership. Whether your path forward runs through the strict liability statute, a negligence claim, or both, understanding the law gives you a clearer picture of your options. If you were bitten by a dog in Colorado, speaking with an experienced personal injury attorney is the most reliable way to evaluate your specific situation. You may also find it helpful to review how neighboring states handle similar cases, including dog bite laws in Wyoming, Utah, and Tennessee, to better appreciate the range of approaches across the country. For those curious about animal bites more broadly, our coverage of snakebite envenoming and animals with the strongest bite force offers additional context on the physical risks different animals present.