County authorities are warning the public to take precautions when going to Avocado Lake after elevated levels of E. coli were found. The Central Valley Regional Water Quality Control identified elevated levels of the bacteria after a sample was collected on Wednesday. The sample surpassed the Statewide Bacteria Water Quality Objectives established by the California State Water Resources Control Board. E. coli is a bacterium found in the intestines of warm-blooded animals and serves as an indicator of fecal pollution in water. Officials say elevated levels may indicate a higher risk of illness for swimmers who interact with the water.