In July 2003, the authors investigated an outbreak of Shigella sonnei infections in Marion County, Oregon. Nineteen confirmed and 37 presumptive cases, mostly young children, were identified. A case-control study implicated play in an interactive fountain in a city park (matched odds ratio undefined; p < .002). The association was confirmed by a cohort study among local schoolchildren (RR [relative risk] = 12.6, p < .001) that allowed the authors to estimate that > 500 persons became ill. Fountain design flaws and inadequate maintenance set the stage for the outbreak. In 2007, the authors surveyed state health departments to assess rules and regulations governing interactive fountains. Thirty of 48 states responding (62%) reported public health regulation of fountains; standards and enforcement capacity varied. Regulation is a relatively new phenomenon; only 13 states (27%) had rules before 2000. A lack of enforceable design and maintenance standards increases the risk of enteric disease transmission at these increasingly popular venues.