Owning a dog brings great joy but also great responsibility. Rarely does an owner want to acknowledge that their favorite pooch has the potential to harm someone. Many states have adopted state-wide laws regarding the responsibilities of a dog owner to control their dog; these laws are generally referred to as “leash laws.”  In Virginia, there is a two-part system. First, there is no state-wide “leash law” but the law empowers local jurisdictions (cities, counties and towns) to adopt regulations concerning control of certain breeds of dogs or at certain times of the year. These local ordinances have the effect of law and are called “running at large” ordinances.  Localities are also empowered to enact ordinances that require a dog owner to have a dog under “immediate control” which means on a leash or under voice control.  These local ordinances also have the effect of law and are called “leash laws”.
Most local jurisdictions in Virginia have some adopted some kind of “leash law.”  Usually these laws require that you, as the owner of your dog, while on your property, must keep your dog under control, which means that your dog is confined to the house, a dog pen, on a secured leash, or generally under immediate voice control. If you take the dog off your property, the law usually requires you have your dog on a leash or under immediate voice control. It is advisable to have the dog on a leash.
The second part of the Virginia system is a state-wide law governing “dangerous dogs.”  Under specific circumstances, if a dog has bitten a person or another dog previously, then the dog is deemed a “dangerous dog.” There is a “Dangerous Dog Registry.” However, this state-wide law is relatively ineffective due to the large number of exceptions. For instance, if the dog bite is determined not to be “serious” by a veterinarian, the law doesn’t apply. If the bite takes place on the property of the dog owner, then the laws doesn’t apply. And there are many other exceptions.
The potential harm from not having your dog on a leash or confined may come in a form other than your dog biting a person. The harm could come from your dog wanting to play and knocking down a bicyclist or motorcyclist. Or the harm could come from scaring or running into a person out for a walk who falls and is injured. In addition, there is also the risk of your dog of being hurt if allowed to run loose.
In general, Virginia is referred to as a “one bite” state or having the “one bite rule” when determining the civil liability of the owner of a dog. This principle says that in order to hold a dog owner responsible for his dog biting someone, the victim must show that the dog has bitten prior to this occasion. (The idea is that the owner is then on notice that the dog might bite again). Actually, Virginia law is broader than this. Even if the dog has not bitten before, if the dog has shown “inclinations or characteristics” in its behavior that would otherwise put the owner on notice the dog is likely to cause injury, then a dog owner has a duty to use ordinary care to prevent an injury. 
So, under this approach, a victim must show that the dog behaved viciously or aggressively on other occasions, and the dog’s owner knew of this behavior. This evidence may be obtained by one or more of the following ways: talking with the owner of the dog, his neighbors, checking with animal control, postal employees, FedEx or UPS drivers, and possibly obtaining the records from the dog’s veterinarian.
However, leash laws and ordinances may create liability for a dog owner even though the owner has no reason to know the dog is likely to bite.  If a dog is allowed to run loose in violation of such an ordinance, or if a dog owner negligently allows the dog to get loose, the owner is liable for injury caused by the dog off the premises of the owner.  To determine if your city or county has a leash law, check http://www.municode.com. If your locale is not listed here, call Animal Control for your area and ask about any “running at large” or “leash law” regulations.
However, Virginia law also says that even if the dog has never bitten before, an owner is on notice of the “general natural inclinations” of the breed or class of dog, and if those “inclinations or characteristics” are of a kind likely to cause injury, then the owner has a duty to use reasonable care to prevent injury. Certain breeds, especially if the breed is one bred to be an attack or fight dog, and the dog is raised that way, are naturally vicious and dangerous. This is often called notice of the “propensities of the breed.”
In summary, the Virginia legislature has passed laws to protect the citizens of our state from dangerous or vicious dogs, and has given the authority to pass more stringent leash laws to the localities. Know the law of your locality and please be a responsible dog owner.
If you have been bitten or suffered injury due to a dog, you should consult an attorney to determine what your rights are.
 See the following for a state-by-state review of dog “leash laws” http://www.animallaw.info/articles/ovusdogleashlaws.htm
 Va. Code sec. 3.2-6538.
 Va. Code sec. 3.2-6539.
 For example, ordinance in the City of Richmond, Virginia: “Sec. 10-172. Restraint or confinement of dogs. All dogs shall be kept under restraint or confined in an enclosure, except as otherwise provided in state law.” See http://municipalcodes.lexisnexis.com/codes/richmondva/. (See also Chapter 10. “Animals” generally).
 Ignoring the fact that, at best, all dogs are domesticated wild animals, the law in Virginia states that a dog owner is not responsible for a bite by his dog unless or until the dog owner knows that the dog is aggressive and is likely to bite. (Some other states have laws that hold a dog owner is always responsible for the damage caused by his dog, which is based on the idea that it is in the nature of dogs to bite, so a dog bite is never a surprise to the owner).
 See Butler v. Frieden, 208 Va. 352, 158 S.E.2d 121 (1967), where the Virginia Supreme Court held that a city ordinance (“leash law”) set the standard of care for a dog owner and if it was violated, that was negligence by the dog owner.
 For instance, see Stout v. Bartholomew, 261 Va. 547, 544 S.E.2d 653 (2001). In that case, although a jury awarded damages to someone bitten by a dog, the trial court entered judgment for the dog owner and the Virginia Supreme Court agreed. The dog had escaped from an invisible fence and caused a motorcyclist to crash. However, noting that (1) the dog owner had successfully used an invisible fence with a previous dog; (2) this dog had never escaped the invisible fence before; (3) an invisible fence is not a method of fencing that is inherently any less reliable than any other method; (4) the dog had not shown propensity to attack cars or motorcycles or people, the Virginia Supreme Court held that there was no evidence that the dog owner did not act reasonably in restraining the dog or that the dog owner had any notice that the dog was likely to cause injury.