The contamination of ground and surface water is primarily a result of human activity. Industry, agriculture, urban development, and even the way we care for the land at our home can affect water quality. Therefore, it is important to have an understanding of how human activities can both directly and indirectly, negatively affect water quality, and in turn threaten drinking water.

Human Activities in the Watershed

It is important to note that a number of natural elements, such as arsenic, mercury and lead, radioactive compounds such as radium and microorganisms such as parasites, bacteria and algae are naturally present in water in small amounts. At low natural levels the presence of these elements, compounds and microorganisms are not a concern. However, when the levels of these elements increase as a result of human activities, they then have the potential to be harmful.

There are two types of surface water and groundwater contamination - point source pollution and non-point source pollution.

Adapted from Pollution Probe's Source Water Protection Primer