Staff and volunteers collect samples on Wednesdays. They are processed using IDEXX Colilert system and incubated for 18 hours before the results are analyzed and posted Thursday afternoons. 

While E. coli is not the only bacteria that could pose a danger to humans, it’s a reliable indicator of the presence of other bacteria and pathogens that are harmful to human health, said MountainTrue Western Regional Director Callie Moore. 

E. coli bacteria enters rivers and streams from sewer and septic system leaks, cattle accessing streams and stormwater runoff. Heavy rains and storms often result in spikes of contamination. Contact with or consumption of contaminated water can cause gastrointestinal illness as well as skin, ear, respiratory, eye, neurologic and wound infections. The most commonly reported symptoms are stomach cramps, diarrhea, nausea, vomiting and low-grade fever. 

See the latest results for the stream you’re considering visiting at swimguide.org.