A water contaminant is a substance which is found in water that has the potential to pose a risk to public health at certain levels. Some contaminants occur naturally in the environment and seep into water sources through erosion. Unfortunately, many of the contaminants found in water are a result of human activities. The industrial wastes from factories, refineries, mines and mills all contain harmful substances which can contaminate water sources.
But many people in developing countries, and people living in rural areas of developed countries (including many First Nations communities) do not take safe drinking water for granted. They understand the relationship that exists between safe drinking water and good health, because they have experienced waterborne disease firsthand.