According to the EPA, actual events of drinking water contamination are rare, and typically do not occur at levels likely to pose health concerns. However, drinking water can get contaminated from naturally occurring sources in the environment or through human and animal activities. Some possible sources of contamination include:
- septic systems,
- underground fuel tanks,
- industrial spills or discharges,
- animal wastes, fertilizers, and pesticides, and
- prolonged periods of heavy rain.