An outbreak of E. coli O157:H7 resulted when the Yaman Restaurant in St. Catherine's, Ontario, Canada, remained open during a water service disruption. When a water main had broken and the restaurant's water was shut off, the restaurant continued to serve food. Without running water, restaurant workers would not be able to wash and sanitize food surfaces, dishes, and utensils. Patrons eating at the restaurant developed infections caused by the same strain of E. coli. The identical strain of E. coli was found on chicken and on a knife found in the restaurant.