Bacteria in water can originate from the intestinal tracts of both
humans and other warm-blooded animals, such as pets, livestock
and wildlife. Human sources include failing septic tanks, leaking
sewer lines, wastewater treatment plants, combined sewer
overflow (CSOs), boat discharges, swimming “accidents” and
urban storm water runoff. In urban watersheds, fecal indicator
bacteria are significantly correlated with human density (Frenzel
and Couvillion, 2002).