Where It Comes From
Soil, plants, and fecal contamination entering water via cracked pipes, stormwater, poor wells, or inadequate disinfection [1][3].
How You Are Exposed
Drinking, cooking, making ice, or brushing teeth with contaminated tap or well water [1][2].
Why It Matters
Coliforms indicate system problems; detection raises risk of pathogens (like E. coli) that cause diarrhea, cramps, and vomiting [1][2][3].
Who Is at Risk
Infants, young children, older adults, pregnant people, and those with weakened immunity [2][3].
How to Lower Your Exposure
Follow advisories; boil water 1 minute (3 minutes at high altitude) before use. Use safe bottled water or certified microbiological purifiers. Maintain, disinfect, and test private wells; fix leaks promptly [1][2][3].
References
- [1]U.S. EPA. Revised Total Coliform Rule (RTCR) and Total Coliform Rule. https://www.epa.gov/ground-water-and-drinking-water/revised-total-coliform-rule-and-total-coliform-rule
- [2]CDC. Boil Water Advisory. https://www.cdc.gov/healthy-water/emergency/drinking/drinking-water-advisories/boil-water-advisory.html
- [3]WHO. Guidelines for Drinking-water Quality, 4th ed., incorporating the 1st addendum – Microbial aspects (indicator bacteria). https://www.who.int/publications/i/item/9789240045064