Trestle Creek Beach users should not swim or wade in the water until further notice, Alberta Health Services says.
The health agency issued a water quality advisory on Wednesday because “elevated levels of fecal bacteria” were found by tests.
Ingesting the water could result in gastrointestinal illness and swimming in it could cause skin, ear and eye infections.
AHS said it will be monitoring the situation.
Trestle Creek is located west of Edmonton, near Entwistle.