What do the numbers mean?
Vermont’s Water Resources Board (WRB) set the E. coli level of 77 organisms per 100 milliliters (a little less than half a cup) in 1990 based on an
illness rate of six acute gastrointestinal illnesses per 1,000 swimming events. This number is significantly lower than the Environmental Protection
Agency’s (EPA) recommended guidelines of 235 E. coli organisms per 100 milliliters. The EPA’s number is based on an illness rate of eight per
1,000 swimmers.
