Published on September 2, 2022

Prospect Lake in Memorial Park is open as of Friday morning after being closed Thursday, Sept. 1 to bodily contact following a positive test for an elevated concentration of E. coli. The lake water was tested a second time on Sept. 1 and staff received the results Sept. 2. The initial test on Aug. 31 returned an E. coli level of 307.6 organisms per 100 milliliters, while the acceptable level for E. coli is 235 organisms per 100 milliliters. Today’s results show the level at 14.6 organisms per 100 milliliters. 

“Shortly after the first sample was taken for testing, a routine water treatment was performed on Wednesday evening, which likely helped improve the water quality,” said Erik Rodriguez, health, safety and environmental specialist with the Parks, Recreation and Cultural Services Department. “It’s great news that Prospect Lake will be open for one of our city’s most popular events, the Labor Day Lift Off.”

According to the Colorado Department of Public Health and Environment (CDPHE), Elevated E. coli concentrations may result from: fecal waste from swimmers, pets or wildlife; improperly disposed dirty diapers; excessive runoff from rain or flood; runoff from urban, suburban or rural areas; or malfunctioning septic systems. For additional information about E. coli, including symptoms of infection, visit

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