By Tori Mason

LITTLETON, Colo. (CBS4) – The swim beach at Chatfield State Park closed Tuesday due to the presence of E. coli.  E. coli is an organism that’s known to cause illness in humans and is most often attributed to fecal material in the water.

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Public health guidelines from CDPHE for natural swim areas require testing for E. coli on a weekly basis. According to Colorado Parks and Wildlife, two tests were conducted recently at Chatfield.

One test came back normal and one came back elevated.

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“Elevated concentrations could be from runoff after the recent rain events. Levels could be raised due to wildlife in the area, improperly disposed waste like diapers, or malfunctioning septic systems,” said Jason Clay, CPW.

CPW says it could also be an error in the testing, so further tests were taken and those results should come back Wednesday. If the results come back normal, then the swim beach would reopen.

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If a laboratory result shows an E. coli concentration above 235 organisms per 100 milliliters, the beach must be closed. The beach will remain closed until E. coli results return to a safe level.

The bacteria can cause diarrhea and other health problems for humans. For more information visit

Tori Mason