By Jennifer McRae

LITTLETON, Colo. (CBS4) – The swim beach at Chatfield State Park reopened Wednesday after it was 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.

(credit: CBS)

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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, which resulted in the closure.

(credit: CBS)

Retesting took place Tuesday and those laboratory tests were made available Wednesday afternoon, showing they had returned to a safe level.

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“Additional tests taken from our swim beach were shown to be well below the levels the CDPHE procedures warrant for a closure,” said Ben Vinci, Chatfield State Park operations manager in a statement. “We had the one irregular sample that caused us to close the swim beach on Tuesday out of an abundance of caution, but the rest of our samples this year have been below the maximum limit. With today’s test results showing the levels are safe, we reopened our swim beach.”

(credit: CBS)

Water quality samples are analyzed for fecal matter, or E. coli. If a laboratory result shows an E. coli concentration above 235 organisms per 100 milliliters, the beach must be closed.

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

Jennifer McRae