We report 3 adult cases of intestinal intussusception associated with enteroviruses occurring in the same geographic areas within a three-week period. Virologic studies include viral RNA detection in stool samples and staining for enterovirus protein by immunoperoxidase technique of the resected intestines. A new mechanism for intussusception associated with enterovirus is proposed. Tap water was implicated in the outbreak. Better monitoring of drinking water may prevent other cases of non-polio enterovirus infection.