CALGARY -- Increased levels of fecal matter means a swimming advisory has been put into effect for Chestermere Lake.

Alberta Health Services is now searching for a cause.

"As AHS is not conducting lake water quality testing this summer due to the COVID-19 pandemic, the City of Chestermere contracted a private company to test lake water quality this summer," City of Chestermere officials said in a release.

"This temporary water quality concern was identified through the city’s regular weekly water quality testing program in partnership with Palliser Environmental Services Ltd. and the Western Irrigation District.

Multiple areas around the lake will be re-tested in the coming days.

"While the beaches and beach areas will remain open during this investigative period, access to the water from the beaches will be closed and signage posted advising of the potential health risks related to entering the water," read the release.

"All swimming areas will remain closed through the weekend and into next week as a precaution.

"Lake users may still use motorized and non-motorized water vessels and access the boat launch as long as they are not swimming in, or otherwise physically entering the water. Beaches are open but water access is not permitted."

Contact with contaminated water can result in gastrointestinal illness and there is the possibility of skin, ear and eye infections.

"As always, visitors and residents are reminded to never drink or cook with untreated water directly from any river, lake or reservoir, at any time," reads the release.

"Water-borne organisms, including fecal bacteria, can cause vomiting and diarrhea. If you have any of these symptoms, contact Health Link at 811 or call your physician."

In July, officials announced limits on the number of beach-goers due to overcrowding.

This advisory will remain in effect until further notice.