CHATFIELD STATE PARK, Colo. (KDVR) — The swimming beach at Chatfield State Park is closed because of elevated levels of bacteria in the water.

Colorado Parks and Wildlife spokesperson Jason Clay said it’s unclear what led to the elevated levels. It could have been caused by runoff from recent rain, fecal matter from humans or wildlife, or even a malfunctioning septic system upstream, Clay said.

“Until we get the further test results back tomorrow, we’ll have it closed off,” Clay said. “If you’re feeling sick for any reason, the smart thing to do would be to contact your doctor.”

E. coli has been known to cause nausea, diarrhea and vomiting, among other symptoms.

Clay said state guidelines only require them to test and close the roped-off swimming section of the beach.

That means people are still free to use the rest of the lake.

Tuesday, only a handful of people were on the beach and in the water near the closure zone, including Mary Jane Smith’s family.

“I feel like as long as we’re having a bath afterwards, and using anti-bacterial soap, that we’ll be safe,” Smith said. “It’s not too much of a threat.”

Smith said she appreciates CPW alerting them to the danger.

“This is a great place to come, and they do a really good job of cleaning up the beaches and making sure everyone’s aware of what’s in the water, which is really awesome,” she said.

CPW said E. coli was found in the water during a round of testing. Additional testing will take about 24 hours, meaning the beach will likely be closed again on Wednesday.

All Colorado state park swim areas and beaches were closed in 2020 to help prevent the community spread of the coronavirus.

A major construction project at Chatfield Reservoir kept the popular swim beach closed for the entire 2018 season.