Microbial contaminants are living organisms that can turn otherwise clear water into a source of disease.

They are often invisible to the eye and can enter drinking water or bathing water through sewage leaks, agricultural runoff, stormwater, or compromised plumbing.

Common microbial contaminants include:

• Bacteria: E. coli, Salmonella, Legionella
• Viruses: Norovirus, Rotavirus, Hepatitis A
• Parasites: Giardia, Cryptosporidium

Health risks:

• Gastrointestinal illness (nausea, vomiting, diarrhea)
• Fever, dehydration, and serious infections
• Potential hospitalization, especially for children, the elderly, or immune-compromised individuals

Important note:

Boiling water, UV disinfection, and certain filtration systems can eliminate or reduce microbial threats — but these risks must be taken seriously, especially for private well users or during boil-water advisories.