into new legislation. Contributing causes Physical Well 5: shallow depth of the well, its being surrounded by fractured bedrock, and its physical location near a source of cattle manure runoff all contributed to Well 5 being unusually susceptible to contamination Chemical Inadequate chlorination of Well 5's water (as well as water throughout the Walkerton PUC system) meant that, once it was contaminated by bacteria such as E. coli, it remained so. Organizational negligence Public Utility Commission staff: Inadequate training and continuing education among staff of the Walkerton PUC meant that those responsible for the safety of the area's water were not equipped to make informed decisions in this area The Walkerton PUC had a long-term history of failing to abide by the minimum water testing and treatment requirements Inadequate monitoring of system water: PUC staff regularly collected fewer samples than required, and collected them from improper areas of the system. Both of these practices were known to potentially lead to false-negative contamination results. Similarly, PUC staff generally failed to perform chlorine residual monitoring tests as often as necessary, and often performed them improperly when they did perform them. Improper chlorination: Though the Ministry of the Environment had repeatedly reminded the PUC of the importance of maintaining the system at a 0.5 mg/L chlorine residual after 15 minutes, PUC staff relied on their personal judgment that this standard was unnecessary due to the water's inherent quality and chose to chlorinate the system to a lesser level, partially in response to community complaints that the system's water tasted of chlorine. Public Utility Commissioners (two elected, one the town's mayor serving ex oficio): Public Utilities Commissioners should have been responsible for hiring and maintaining informed and capable PUC staff, beginning with senior management; this was neglected in Walkerton, as the commissioners felt that their responsibilities encompassed only "budgeting and financial aspects of the operation". Commissioners relied on PUC manager Stan Koebel to make policy and inform the Commission of water quality-related events of interest, even when commissioners were or should have been aware of such information and responsible for policy-setting. Commissioners also failed to review whether Koebel was performing these aspects of his job adequately. Commissioners were offered no education on the topic of water safety, and none was required of them in order to be elected or to serve. Commissioners typically did not consider this knowledge a requirement for doing their jobs,