http://www.cdc.gov/healthyswimming/
National Center for Infectious Diseases, Centers for Disease Control and Prevention
Every year, millions of people visit “recreational water” sites, such as swimming pools, water parks, hot tubs, lakes, rivers, or the ocean. This Web site provides information for swimmers, pool operators, and public health professionals to improve the swimming experience by raising awareness about the spread of recreational water illnesses (RWIs). Practicing "Healthy Swimming" behaviors can reduce the risk of getting ill.