Update August 23, 2019
Samples collected by Salt Lake County at Big Cottonwood Creek at Creekside Park on August 22, 2019, showed E. coli levels above the maximum water quality standard.
Utah uses the Most Probable Number (MPN) method to estimate the concentration of E. coli in a water sample. The presence of a high number of indicator organisms such as E. coli signals a higher probability of pathogens in the water. The threshold of 409 MPN of bacterial density per 100 milliliters (mL) of water relates to a risk factor of 8 illnesses per 1,000 swimmers. As the value of the MPN increases above 409 MPN, the risk of illness if exposed to contaminated waters also increases.
E. coli concentrations from the August 22, 2019, sample were 1413.6 MPN per 100/mL