Public health plays an important role in our overall health care system. Several significant achievements are directly attributable to public health. For instance, the response to the London cholera epidemics of the late 1800s is a well-known, classic example of public health. In that case, no single individual had an incentive to bear the full cost of repairing sewer lines that were leaking into the water supply because all the costs would be borne by the repairer, while the benefits would accrue to community at large. Thus, keeping community water supplies free from sewage contamination became a public health matter, as opposed to a private health matter.