As development in our modern society increases, there are growing numbers of threats that could contaminate drinking water. Actual events of serious drinking water contamination occur infrequently and typically not at levels posing near-term health concerns. With the threats of such events increasing, we cannot take drinking water safety for granted. Continued Microbiological and chemical contaminants can enter water supplies. These materials can be the result of human activity or can be found in nature.
Chemicals can migrate from disposal sites and contaminate sources of drinking water.
Animal wastes and pesticides may be carried to lakes and streams by rainfall runoff or snow melt. Human wastes may be discharged to receiving waters that ultimately flow to water bodies used for drinking water. Health Problems Continued Coliform bacteria from human and animal wastes may be found in drinking water if the water is not properly treated or disinfected. These bacteria are used as indicators that other harmful organisms may be in the water. The potential for health problems from drinking water is illustrated by localized outbreaks of water-borne disease.