The Walkerton E. coli outbreak was the result of a contamination of the drinking water supply of Walkerton, Ontario, Canada, with E. coli and Campylobacter jejuni bacteria. The water supply was contaminated as a result of improper water treatment following heavy rainfall in late April and early May 2000, that had drawn bacteria from the manure of nearby cattle used to fertilize crops into the shallow aquifer of a nearby well. The first reported case was on May 17. The contamination caused gastroenteritis and sickened more than 2,000 people and resulted in six deaths. Subsequently, Associate Chief Justice of Ontario, Dennis O'Connor launched an inquiry into the outbreak, called the Walkerton Inquiry. Walkerton Public Utilities Commission operators Stan and Frank Koebel, neither of whom had any formal training, were sentenced on December 20, 2004, after pleading guilty to charges of common nuisance stemming from the contamination—Stan to one year in jail, and Frank to nine months house arrest. As a result, stricter water treatment guidelines were put in place by the government. Town background Walkerton, Ontario is a small township in the municipality of Brockton, northwest of Toronto. It serves as the administrative centre of Brockton, into which it was merged in 1999, and as the county seat of Bruce County. The population of Walkerton in 1996 was recorded as 5,036 individuals in an area of . At the time of the 2000 events, the town's drinking water was drawn from three chlorinated wells to the west and southwest of the town. The wells were owned and operated by the Walkerton Public Utilities Commission (PUC), which was managed by Stan Koebel and run by foreman Frank Koebel. Contamination background Walkerton Public Utilities Commission System operators In 2000, the Walkerton Public Utilities Commission was under the supervision of two men, brothers Stan and Frank Koebel. Both men had been working for the Walkerton Public Utilities Commission (PUC) since the 1970s, when they were teenagers and their father worked at the PUC. Neither man had formal training in public utility operation or in water management, but by 2000, both had been promoted to management positions on the basis of their experience. Both brothers carried certification as class 3 water distribution system operators, licences obtained through a grandfathering program run by the Ministry of the Environment (MOE) and based on their work experience in their positions. Though Ontario law required that water systems