Skip to main content

Sources of drinking water contamination

Drinking water can become contaminated when germs and chemicals are present in a water sources or water systems in amounts high enough to make people sick. The U.S. Environmental Protection Agency (EPA) sets water quality standards and regulations for Group A public water systems, which are enforced by the state Office of Drinking water.

However, the EPA does not regulate Group B and individual private wells. Group B and private well users are responsible for monitoring their own water quality and keeping it free from contamination. Group B and private wells should pay close attention to potential sources of contamination in their areas.

Potential contamination sources include

  • Fertilizers, pesticides, or other chemicals that have been applied to land near the water
  • Concentrated animal activities, such as stables, barns, and feeding pens
  • Manufacturing operations
  • On-site sewage systems
  • Sewer overflows
  • Flooding
  • Storm water
  • Wildlife
  • Rocks and soil that naturally have chemicals and minerals such as arsenic
  • Cracks in water pipes and other problems with the distribution system

Learn more about drinking water contamination in this guidance from Cornell University (PDF) or guidance from the Groundwater Foundation.

expand_less