One of the most common effects of drinking contaminated water is gastrointestinal illness. This can include symptoms such as diarrhea, vomiting, cramps and nausea.
Contaminated water can also contain various dangerous chemicals, such as heavy metals, pesticides, and other pollutants. The most common sources of contaminated water include:
Agricultural runoff is major source of contamination. When farmers use pesticides and fertilizers, they can run off into nearby streams, rivers, and lakes, polluting the water.