What contaminants do Ontarios drinking water quality standards cover?
Drinking water quality standards under O. Reg 169/03 cover three different types of contaminants: Microbiological: The province has set standards for E. coli, fecal coliforms and total coliforms. Under O. Reg. 169/03 these parameters should not be detectable in drinking water. This Regulation also prescribes numerical limits for general bacteria populations that may be present in drinking water. Coliforms are bacteria common in the environment and come from human and animal waste. Although most are harmless, their presence may indicate that there are other harmful bacteria in the water. In addition, some bacteria can have a wide range of adverse health impacts — they may cause acute illnesses such as gastroenteritis, or they may be a serious public health risk. For example, the infiltration of E. coli 157/H7 bacteria into a municipal well was a cause of seven deaths in Walkerton, Ontario in May 2000. Operators at drinking water treatment plants are required to test regularly for colif
