E. coli in Drinking Water

EPA Limit: 0 (any detection is a violation)

E. coli is the most serious indicator of fecal contamination in drinking water. Any detection triggers an immediate violation and typically a boil-water advisory. Under the RTCR, E. coli-positive results are treated as acute MCL violations.

Where Does E. coli Come From?

E. coli bacteria in drinking water indicate fecal contamination from human or animal waste. This can occur through sewage overflows, failing septic systems, or agricultural runoff reaching the water source or infiltrating the distribution system.

Health Risks

E. coli contamination can cause severe gastrointestinal illness, including bloody diarrhea, vomiting, and in rare cases, hemolytic uremic syndrome (HUS), which can lead to kidney failure. Children, elderly, and immunocompromised individuals are at highest risk.

What Should I Do?

Any detection of E. coli is serious. Follow boil-water advisories immediately. Bring water to a rolling boil for at least one minute before use. Use bottled water if boiling is not possible. Do not use untreated water for drinking, brushing teeth, or making ice.