There is no exact way in which to determine when a business owner or public entity is legally responsible for a customer's injuries in a slip or trip and fall accident. The fundemental question is whether the business or property owner acted with reasonable care so that slipping or tripping was not likely to happen. Just as important is whether the customer was careless in not seeing or avoiding the condition that caused the fall and subsequent injury.

Usually, a person injured in a slip and fall on someone else's property must prove that the cause of the accident was a "dangerous condition," and furthermore, that the owner of the property was aware of the dangerous condition but failed to remedy it. A dangerous condition is defined as some condition that presents an unreasonable risk to a person on the property, and it must be a condition that the injured party should not have anticipated under the circumstances. This latter requirement is important, as it indicates that people must be aware of, and avoid, obvious dangers.

• In order to establish that a business owner knew of a dangerous condition, it must be shown that either:
• The owner was responsible for the condition
• The owner was aware the condition existed and negligently failed to correct it
• The condition existed for a length of time that the owner should have discovered and corrected it prior to the slip and fall incident in question.

For a business owner to be held liable, it must have been foreseeable that his or her negligence would create the danger at issue.

Less frequently, a person injured in a slip or trip and fall case can prove negligence by proving that the property owner violated some relevant statute. Building codes often dictate when and where handrails and other similar features must be installed. Therefore, if a customer falls on a stairway that did not have the appropriate handrails, and the lack of the handrail caused the injuries, the customer may have a valid claim against the building owner based on his or her building code violation.