Tourists who traveled on a variety of bus tours through Alaska, and the Yukon Territory (Canada), developed gastroenteritis. An investigation into the cause of the illnesses was initiated. The itineraries were examined. Illnesses were traced back to a specific restaurant that was common for the various bus tours. The epidemiologic investigation implicated the consumption of water while dining at the restaurant. Most of the employees of this restaurant had concurrently been ill. One employee was ill shortly before the first illnesses occurred. He lived in a building connected to a septic pit near the restaurant. The septic pit was found to be contaminating the well water for the restaurant. Genotype 2/P2B, small round structured virus, SRSV, or calicivirus, were isolated from stool samples and water samples.