As a follow up:
http://www.epa.gov/safewater/contaminants/ecoli.html
from it:
Basic Information about E. coli 0157:H7 in Drinking Water
Total Coliforms (including E. coli 0157:H7) at a Glance
Maximum Contaminant Level
MCL = 5.0% 1
Maximum Contaminant Level Goal MCLG = 0 ppm
Health Effects
Not a health threat in itself; it is used to indicate whether other potentially harmful bacteria may be present. 2
Sources of contamination
Coliforms are naturally present in the environment; as well as feces; fecal coliforms and E. coli only come from human and animal fecal waste.
For other contaminants and their MCLs, visit the MCL list page.
On this page
Introduction
Questions and answers
Other resources
Centers for Disease Control and Prevention's fact sheet on E. coli
Food and Drug Administration's Bad Bug Book
Introduction
One of hundreds of strains of the bacterium Escherichia coli. E. coli O157:H7 is an emerging cause of foodborne and waterborne illness. Although most strains of E. coli are harmless and live in the intestines of healthy humans and animals, this strain produces a powerful toxin and can cause severe illness.
E. coli O157:H7 was first recognized as a cause of illness during an outbreak in 1982 traced to contaminated hamburgers. Since then, most infections are believed to have come from eating undercooked ground beef.
However, some have been waterborne. In 1999, people became sick after drinking contaminated water in Washington County, New York and swimming in contaminated water in Clark County, Washington.
Information about the health effects of E. coli O157:H7, and actions you can take to protect yourself and your family from E. coli infection is provided below.
