Reporting is done Annually and published biennially in the Morbidity Mortality Weekly Report (MMWR) Surveillance Summaries. Electronic reporting was launched in 2009 via the National Outbreak Reporting System (NORS). Two criteria must be met for an event to be defined as a waterborne-disease outbreak associated with drinking water: 1) two or more persons epidemiologically linked by location of exposure to water, by time and characteristics of illness and 2) the epidemiologic evidence must implicate water as the probable source of illness. The data include only outbreaks from infectious agents and chemical poisoning from water intended for drinking. Community water systems are public water systems that have at least 15 service connections or serve an average of 25 residents for 60 days/year. A community water system serves year-round residents of a community, subdivision, or mobile home park.