The City of Columbus determined that the source of contamination to its water supply was Well 3-II, located on the Bartholomew County 4-H Fairgrounds. The well -- one of 15 operated by the city -- was removed from service at 3 p.m. Friday, and additional bacteriological samples were taken. By mid-afternoon Saturday, all five samples taken on Friday came back positive for fecal material. But since the well was separated from the rest of the city water supply, the Indiana Department of Environmental Management allowed the city to lift its boil-water order, which it did at 3:30 p.m. Saturday.