Statistical data have been collected on waterborne disease outbreaks in the U.S. since 1920. 1 21 During 1920 through 1936, these data were collected and compiled by Gorman and Wolman. 1 , 2 In subsequent periods,* data were collected by several federal agencies, 3 21 and summaries were prepared by Eliassen and Cummings, 4 Weibel et al., 5 Craun and McCabe, 8 and Craun et al. 12 The Centers for Disease Control (CDC) and the Environmental Protection Agency (EPA) have conducted waterborne disease investigation and surveillance activities and have published information on waterborne outbreaks annually since 1971. 13 21 All the available data on waterborne outbreaks were compiled and examined to provide a historical perspective of the epidemiology of waterborne disease over the past 61 years. 11 This summary is intended to supplement the reviews and analyses of waterborne outbreaks contained in previously published articles. 1 , 4 , 5 , 8 , 12