| Contaminants | Common Effects |
| Lead | Birth defects, kidney disease, infant mortality |
| Copper | Liver or kidney damage, gastrointestinal illness |
| Arsenic | Skin damage with circulatory problems, risk of cancer |
| Nitrate | Infant illness or death, Blue Baby Syndrome |
| Nitrite | infant illness or death, Blue Baby Syndrome |
| Radioactive Substances | Increased risk of cancer |
| Fluoride | Bone disease |
| Mercury | Kidney damage |
| Chlorite | Anemia, nervous system damage |
| Microorganisms | Gastrointestinal illnesses |
| Viruses | Gastrointestinal illnesses |